API¶
This part of the documentation lists the full API reference of all public classes and functions.
Decorators¶
- click.command(name: Callable[[...], Any]) Command ¶
- click.command(name: str | None, cls: type[CmdType], **attrs: Any) Callable[[Callable[[...], Any]], CmdType]
- click.command(name: None = None, *, cls: type[CmdType], **attrs: Any) Callable[[Callable[[...], Any]], CmdType]
- click.command(name: str | None = None, cls: None = None, **attrs: Any) Callable[[Callable[[...], Any]], Command]
Creates a new
Command
and uses the decorated function as callback. This will also automatically attach all decoratedoption()
s andargument()
s as parameters to the command.The name of the command defaults to the name of the function, converted to lowercase, with underscores
_
replaced by dashes-
, and the suffixes_command
,_cmd
,_group
, and_grp
are removed. For example,init_data_command
becomesinit-data
.All keyword arguments are forwarded to the underlying command class. For the
params
argument, any decorated params are appended to the end of the list.Once decorated the function turns into a
Command
instance that can be invoked as a command line utility or be attached to a commandGroup
.- Parameters:
name – The name of the command. Defaults to modifying the function’s name as described above.
cls – The command class to create. Defaults to
Command
.
Changed in version 8.2: The suffixes
_command
,_cmd
,_group
, and_grp
are removed when generating the name.Changelog
Changed in version 8.1: This decorator can be applied without parentheses.
Changed in version 8.1: The
params
argument can be used. Decorated params are appended to the end of the list.
- click.group(name: Callable[[...], Any]) Group ¶
- click.group(name: str | None, cls: type[GrpType], **attrs: Any) Callable[[Callable[[...], Any]], GrpType]
- click.group(name: None = None, *, cls: type[GrpType], **attrs: Any) Callable[[Callable[[...], Any]], GrpType]
- click.group(name: str | None = None, cls: None = None, **attrs: Any) Callable[[Callable[[...], Any]], Group]
Creates a new
Group
with a function as callback. This works otherwise the same ascommand()
just that the cls parameter is set toGroup
.Changelog
Changed in version 8.1: This decorator can be applied without parentheses.
- click.argument(*param_decls, cls=None, **attrs)¶
Attaches an argument to the command. All positional arguments are passed as parameter declarations to
Argument
; all keyword arguments are forwarded unchanged (exceptcls
). This is equivalent to creating anArgument
instance manually and attaching it to theCommand.params
list.For the default argument class, refer to
Argument
andParameter
for descriptions of parameters.
- click.option(*param_decls, cls=None, **attrs)¶
Attaches an option to the command. All positional arguments are passed as parameter declarations to
Option
; all keyword arguments are forwarded unchanged (exceptcls
). This is equivalent to creating anOption
instance manually and attaching it to theCommand.params
list.For the default option class, refer to
Option
andParameter
for descriptions of parameters.
- click.password_option(*param_decls, **kwargs)¶
Add a
--password
option which prompts for a password, hiding input and asking to enter the value again for confirmation.
- click.confirmation_option(*param_decls, **kwargs)¶
Add a
--yes
option which shows a prompt before continuing if not passed. If the prompt is declined, the program will exit.
- click.version_option(version=None, *param_decls, package_name=None, prog_name=None, message=None, **kwargs)¶
Add a
--version
option which immediately prints the version number and exits the program.If
version
is not provided, Click will try to detect it usingimportlib.metadata.version()
to get the version for thepackage_name
.If
package_name
is not provided, Click will try to detect it by inspecting the stack frames. This will be used to detect the version, so it must match the name of the installed package.- Parameters:
version (str | None) – The version number to show. If not provided, Click will try to detect it.
param_decls (str) – One or more option names. Defaults to the single value
"--version"
.package_name (str | None) – The package name to detect the version from. If not provided, Click will try to detect it.
prog_name (str | None) – The name of the CLI to show in the message. If not provided, it will be detected from the command.
message (str | None) – The message to show. The values
%(prog)s
,%(package)s
, and%(version)s
are available. Defaults to"%(prog)s, version %(version)s"
.
- Raises:
RuntimeError –
version
could not be detected.- Return type:
Callable[[FC], FC]
Changelog
Changed in version 8.0: Add the
package_name
parameter, and the%(package)s
value for messages.Changed in version 8.0: Use
importlib.metadata
instead ofpkg_resources
. The version is detected based on the package name, not the entry point name. The Python package name must match the installed package name, or be passed withpackage_name=
.
- click.help_option(*param_decls, **kwargs)¶
Add a
--help
option which immediately prints the help page and exits the program.This is usually unnecessary, as the
--help
option is added to each command automatically unlessadd_help_option=False
is passed.
- click.pass_context(f)¶
Marks a callback as wanting to receive the current context object as first argument.
- Parameters:
f (t.Callable[te.Concatenate[Context, P], R]) –
- Return type:
t.Callable[P, R]
- click.pass_obj(f)¶
Similar to
pass_context()
, but only pass the object on the context onwards (Context.obj
). This is useful if that object represents the state of a nested system.- Parameters:
f (t.Callable[te.Concatenate[T, P], R]) –
- Return type:
t.Callable[P, R]
- click.make_pass_decorator(object_type, ensure=False)¶
Given an object type this creates a decorator that will work similar to
pass_obj()
but instead of passing the object of the current context, it will find the innermost context of typeobject_type()
.This generates a decorator that works roughly like this:
from functools import update_wrapper def decorator(f): @pass_context def new_func(ctx, *args, **kwargs): obj = ctx.find_object(object_type) return ctx.invoke(f, obj, *args, **kwargs) return update_wrapper(new_func, f) return decorator
- click.decorators.pass_meta_key(key, *, doc_description=None)¶
Create a decorator that passes a key from
click.Context.meta
as the first argument to the decorated function.- Parameters:
- Return type:
t.Callable[[t.Callable[te.Concatenate[T, P], R]], t.Callable[P, R]]
Changelog
New in version 8.0.
Utilities¶
- click.echo(message=None, file=None, nl=True, err=False, color=None)¶
Print a message and newline to stdout or a file. This should be used instead of
print()
because it provides better support for different data, files, and environments.Compared to
print()
, this does the following:Ensures that the output encoding is not misconfigured on Linux.
Supports Unicode in the Windows console.
Supports writing to binary outputs, and supports writing bytes to text outputs.
Supports colors and styles on Windows.
Removes ANSI color and style codes if the output does not look like an interactive terminal.
Always flushes the output.
- Parameters:
message (Any | None) – The string or bytes to output. Other objects are converted to strings.
file (IO[Any] | None) – The file to write to. Defaults to
stdout
.err (bool) – Write to
stderr
instead ofstdout
.nl (bool) – Print a newline after the message. Enabled by default.
color (bool | None) – Force showing or hiding colors and other styles. By default Click will remove color if the output does not look like an interactive terminal.
- Return type:
None
Changelog
Changed in version 6.0: Support Unicode output on the Windows console. Click does not modify
sys.stdout
, sosys.stdout.write()
andprint()
will still not support Unicode.Changed in version 4.0: Added the
color
parameter.New in version 3.0: Added the
err
parameter.Changed in version 2.0: Support colors on Windows if colorama is installed.
- click.echo_via_pager(text_or_generator, color=None)¶
This function takes a text and shows it via an environment specific pager on stdout.
Changelog
Changed in version 3.0: Added the color flag.
- click.prompt(text, default=None, hide_input=False, confirmation_prompt=False, type=None, value_proc=None, prompt_suffix=': ', show_default=True, err=False, show_choices=True)¶
Prompts a user for input. This is a convenience function that can be used to prompt a user for input later.
If the user aborts the input by sending an interrupt signal, this function will catch it and raise a
Abort
exception.- Parameters:
text (str) – the text to show for the prompt.
default (Any | None) – the default value to use if no input happens. If this is not given it will prompt until it’s aborted.
hide_input (bool) – if this is set to true then the input value will be hidden.
confirmation_prompt (bool | str) – Prompt a second time to confirm the value. Can be set to a string instead of
True
to customize the message.type (ParamType | Any | None) – the type to use to check the value against.
value_proc (Callable[[str], Any] | None) – if this parameter is provided it’s a function that is invoked instead of the type conversion to convert a value.
prompt_suffix (str) – a suffix that should be added to the prompt.
show_default (bool) – shows or hides the default value in the prompt.
err (bool) – if set to true the file defaults to
stderr
instead ofstdout
, the same as with echo.show_choices (bool) – Show or hide choices if the passed type is a Choice. For example if type is a Choice of either day or week, show_choices is true and text is “Group by” then the prompt will be “Group by (day, week): “.
- Return type:
Changelog
New in version 8.0:
confirmation_prompt
can be a custom string.New in version 7.0: Added the
show_choices
parameter.New in version 6.0: Added unicode support for cmd.exe on Windows.
New in version 4.0: Added the err parameter.
- click.confirm(text, default=False, abort=False, prompt_suffix=': ', show_default=True, err=False)¶
Prompts for confirmation (yes/no question).
If the user aborts the input by sending a interrupt signal this function will catch it and raise a
Abort
exception.- Parameters:
text (str) – the question to ask.
default (bool | None) – The default value to use when no input is given. If
None
, repeat until input is given.abort (bool) – if this is set to True a negative answer aborts the exception by raising
Abort
.prompt_suffix (str) – a suffix that should be added to the prompt.
show_default (bool) – shows or hides the default value in the prompt.
err (bool) – if set to true the file defaults to
stderr
instead ofstdout
, the same as with echo.
- Return type:
Changelog
Changed in version 8.0: Repeat until input is given if
default
isNone
.New in version 4.0: Added the
err
parameter.
- click.progressbar(iterable=None, length=None, label=None, show_eta=True, show_percent=None, show_pos=False, item_show_func=None, fill_char='#', empty_char='-', bar_template='%(label)s [%(bar)s] %(info)s', info_sep=' ', width=36, file=None, color=None, update_min_steps=1)¶
This function creates an iterable context manager that can be used to iterate over something while showing a progress bar. It will either iterate over the iterable or length items (that are counted up). While iteration happens, this function will print a rendered progress bar to the given file (defaults to stdout) and will attempt to calculate remaining time and more. By default, this progress bar will not be rendered if the file is not a terminal.
The context manager creates the progress bar. When the context manager is entered the progress bar is already created. With every iteration over the progress bar, the iterable passed to the bar is advanced and the bar is updated. When the context manager exits, a newline is printed and the progress bar is finalized on screen.
Note: The progress bar is currently designed for use cases where the total progress can be expected to take at least several seconds. Because of this, the ProgressBar class object won’t display progress that is considered too fast, and progress where the time between steps is less than a second.
No printing must happen or the progress bar will be unintentionally destroyed.
Example usage:
with progressbar(items) as bar: for item in bar: do_something_with(item)
Alternatively, if no iterable is specified, one can manually update the progress bar through the update() method instead of directly iterating over the progress bar. The update method accepts the number of steps to increment the bar with:
with progressbar(length=chunks.total_bytes) as bar: for chunk in chunks: process_chunk(chunk) bar.update(chunks.bytes)
The
update()
method also takes an optional value specifying thecurrent_item
at the new position. This is useful when used together withitem_show_func
to customize the output for each manual step:with click.progressbar( length=total_size, label='Unzipping archive', item_show_func=lambda a: a.filename ) as bar: for archive in zip_file: archive.extract() bar.update(archive.size, archive)
- Parameters:
iterable (cabc.Iterable[V] | None) – an iterable to iterate over. If not provided the length is required.
length (int | None) – the number of items to iterate over. By default the progressbar will attempt to ask the iterator about its length, which might or might not work. If an iterable is also provided this parameter can be used to override the length. If an iterable is not provided the progress bar will iterate over a range of that length.
label (str | None) – the label to show next to the progress bar.
show_eta (bool) – enables or disables the estimated time display. This is automatically disabled if the length cannot be determined.
show_percent (bool | None) – enables or disables the percentage display. The default is True if the iterable has a length or False if not.
show_pos (bool) – enables or disables the absolute position display. The default is False.
item_show_func (t.Callable[[V | None], str | None] | None) – A function called with the current item which can return a string to show next to the progress bar. If the function returns
None
nothing is shown. The current item can beNone
, such as when entering and exiting the bar.fill_char (str) – the character to use to show the filled part of the progress bar.
empty_char (str) – the character to use to show the non-filled part of the progress bar.
bar_template (str) – the format string to use as template for the bar. The parameters in it are
label
for the label,bar
for the progress bar andinfo
for the info section.info_sep (str) – the separator between multiple info items (eta etc.)
width (int) – the width of the progress bar in characters, 0 means full terminal width
file (t.TextIO | None) – The file to write to. If this is not a terminal then only the label is printed.
color (bool | None) – controls if the terminal supports ANSI colors or not. The default is autodetection. This is only needed if ANSI codes are included anywhere in the progress bar output which is not the case by default.
update_min_steps (int) – Render only when this many updates have completed. This allows tuning for very fast iterators.
- Return type:
ProgressBar[V]
Changelog
Changed in version 8.0: Output is shown even if execution time is less than 0.5 seconds.
Changed in version 8.0:
item_show_func
shows the current item, not the previous one.Changed in version 8.0: Labels are echoed if the output is not a TTY. Reverts a change in 7.0 that removed all output.
New in version 8.0: Added the
update_min_steps
parameter.Changed in version 4.0: Added the
color
parameter. Added theupdate
method to the object.New in version 2.0.
- click.clear()¶
Clears the terminal screen. This will have the effect of clearing the whole visible space of the terminal and moving the cursor to the top left. This does not do anything if not connected to a terminal.
Changelog
New in version 2.0.
- Return type:
None
- click.style(text, fg=None, bg=None, bold=None, dim=None, underline=None, overline=None, italic=None, blink=None, reverse=None, strikethrough=None, reset=True)¶
Styles a text with ANSI styles and returns the new string. By default the styling is self contained which means that at the end of the string a reset code is issued. This can be prevented by passing
reset=False
.Examples:
click.echo(click.style('Hello World!', fg='green')) click.echo(click.style('ATTENTION!', blink=True)) click.echo(click.style('Some things', reverse=True, fg='cyan')) click.echo(click.style('More colors', fg=(255, 12, 128), bg=117))
Supported color names:
black
(might be a gray)red
green
yellow
(might be an orange)blue
magenta
cyan
white
(might be light gray)bright_black
bright_red
bright_green
bright_yellow
bright_blue
bright_magenta
bright_cyan
bright_white
reset
(reset the color code only)
If the terminal supports it, color may also be specified as:
An integer in the interval [0, 255]. The terminal must support 8-bit/256-color mode.
An RGB tuple of three integers in [0, 255]. The terminal must support 24-bit/true-color mode.
See https://en.wikipedia.org/wiki/ANSI_color and https://gist.github.com/XVilka/8346728 for more information.
- Parameters:
text (Any) – the string to style with ansi codes.
fg (int | tuple[int, int, int] | str | None) – if provided this will become the foreground color.
bg (int | tuple[int, int, int] | str | None) – if provided this will become the background color.
bold (bool | None) – if provided this will enable or disable bold mode.
dim (bool | None) – if provided this will enable or disable dim mode. This is badly supported.
underline (bool | None) – if provided this will enable or disable underline.
overline (bool | None) – if provided this will enable or disable overline.
italic (bool | None) – if provided this will enable or disable italic.
blink (bool | None) – if provided this will enable or disable blinking.
reverse (bool | None) – if provided this will enable or disable inverse rendering (foreground becomes background and the other way round).
strikethrough (bool | None) – if provided this will enable or disable striking through text.
reset (bool) – by default a reset-all code is added at the end of the string which means that styles do not carry over. This can be disabled to compose styles.
- Return type:
Changelog
Changed in version 8.0: A non-string
message
is converted to a string.Changed in version 8.0: Added support for 256 and RGB color codes.
Changed in version 8.0: Added the
strikethrough
,italic
, andoverline
parameters.Changed in version 7.0: Added support for bright colors.
New in version 2.0.
- click.unstyle(text)¶
Removes ANSI styling information from a string. Usually it’s not necessary to use this function as Click’s echo function will automatically remove styling if necessary.
Changelog
New in version 2.0.
- click.secho(message=None, file=None, nl=True, err=False, color=None, **styles)¶
This function combines
echo()
andstyle()
into one call. As such the following two calls are the same:click.secho('Hello World!', fg='green') click.echo(click.style('Hello World!', fg='green'))
All keyword arguments are forwarded to the underlying functions depending on which one they go with.
Non-string types will be converted to
str
. However,bytes
are passed directly toecho()
without applying style. If you want to style bytes that represent text, callbytes.decode()
first.Changelog
Changed in version 8.0: A non-string
message
is converted to a string. Bytes are passed through without style applied.New in version 2.0.
- click.edit(text=None, editor=None, env=None, require_save=True, extension='.txt', filename=None)¶
Edits the given text in the defined editor. If an editor is given (should be the full path to the executable but the regular operating system search path is used for finding the executable) it overrides the detected editor. Optionally, some environment variables can be used. If the editor is closed without changes, None is returned. In case a file is edited directly the return value is always None and require_save and extension are ignored.
If the editor cannot be opened a
UsageError
is raised.Note for Windows: to simplify cross-platform usage, the newlines are automatically converted from POSIX to Windows and vice versa. As such, the message here will have
\n
as newline markers.- Parameters:
text (AnyStr | None) – the text to edit.
editor (str | None) – optionally the editor to use. Defaults to automatic detection.
env (Mapping[str, str] | None) – environment variables to forward to the editor.
require_save (bool) – if this is true, then not saving in the editor will make the return value become None.
extension (str) – the extension to tell the editor about. This defaults to .txt but changing this might change syntax highlighting.
filename (str | None) – if provided it will edit this file instead of the provided text contents. It will not use a temporary file as an indirection in that case.
- Return type:
AnyStr | None
- click.launch(url, wait=False, locate=False)¶
This function launches the given URL (or filename) in the default viewer application for this file type. If this is an executable, it might launch the executable in a new session. The return value is the exit code of the launched application. Usually,
0
indicates success.Examples:
click.launch('https://click.palletsprojects.com/') click.launch('/my/downloaded/file', locate=True)
Changelog
New in version 2.0.
- Parameters:
url (str) – URL or filename of the thing to launch.
wait (bool) – Wait for the program to exit before returning. This only works if the launched program blocks. In particular,
xdg-open
on Linux does not block.locate (bool) – if this is set to True then instead of launching the application associated with the URL it will attempt to launch a file manager with the file located. This might have weird effects if the URL does not point to the filesystem.
- Return type:
- click.getchar(echo=False)¶
Fetches a single character from the terminal and returns it. This will always return a unicode character and under certain rare circumstances this might return more than one character. The situations which more than one character is returned is when for whatever reason multiple characters end up in the terminal buffer or standard input was not actually a terminal.
Note that this will always read from the terminal, even if something is piped into the standard input.
Note for Windows: in rare cases when typing non-ASCII characters, this function might wait for a second character and then return both at once. This is because certain Unicode characters look like special-key markers.
Changelog
New in version 2.0.
- click.pause(info=None, err=False)¶
This command stops execution and waits for the user to press any key to continue. This is similar to the Windows batch “pause” command. If the program is not run through a terminal, this command will instead do nothing.
Changelog
New in version 4.0: Added the err parameter.
New in version 2.0.
- click.get_binary_stream(name)¶
Returns a system stream for byte processing.
- click.get_text_stream(name, encoding=None, errors='strict')¶
Returns a system stream for text processing. This usually returns a wrapped stream around a binary stream returned from
get_binary_stream()
but it also can take shortcuts for already correctly configured streams.
- click.open_file(filename, mode='r', encoding=None, errors='strict', lazy=False, atomic=False)¶
Open a file, with extra behavior to handle
'-'
to indicate a standard stream, lazy open on write, and atomic write. Similar to the behavior of theFile
param type.If
'-'
is given to openstdout
orstdin
, the stream is wrapped so that using it in a context manager will not close it. This makes it possible to use the function without accidentally closing a standard stream:with open_file(filename) as f: ...
- Parameters:
filename (str) – The name of the file to open, or
'-'
forstdin
/stdout
.mode (str) – The mode in which to open the file.
encoding (str | None) – The encoding to decode or encode a file opened in text mode.
errors (str | None) – The error handling mode.
lazy (bool) – Wait to open the file until it is accessed. For read mode, the file is temporarily opened to raise access errors early, then closed until it is read again.
atomic (bool) – Write to a temporary file and replace the given file on close.
- Return type:
Changelog
New in version 3.0.
- click.get_app_dir(app_name, roaming=True, force_posix=False)¶
Returns the config folder for the application. The default behavior is to return whatever is most appropriate for the operating system.
To give you an idea, for an app called
"Foo Bar"
, something like the following folders could be returned:- Mac OS X:
~/Library/Application Support/Foo Bar
- Mac OS X (POSIX):
~/.foo-bar
- Unix:
~/.config/foo-bar
- Unix (POSIX):
~/.foo-bar
- Windows (roaming):
C:\Users\<user>\AppData\Roaming\Foo Bar
- Windows (not roaming):
C:\Users\<user>\AppData\Local\Foo Bar
Changelog
New in version 2.0.
- Parameters:
app_name (str) – the application name. This should be properly capitalized and can contain whitespace.
roaming (bool) – controls if the folder should be roaming or not on Windows. Has no effect otherwise.
force_posix (bool) – if this is set to True then on any POSIX system the folder will be stored in the home folder with a leading dot instead of the XDG config home or darwin’s application support folder.
- Return type:
- click.format_filename(filename, shorten=False)¶
Format a filename as a string for display. Ensures the filename can be displayed by replacing any invalid bytes or surrogate escapes in the name with the replacement character
�
.Invalid bytes or surrogate escapes will raise an error when written to a stream with
errors="strict". This will typically happen with ``stdout
when the locale is something likeen_GB.UTF-8
.Many scenarios are safe to write surrogates though, due to PEP 538 and PEP 540, including:
Writing to
stderr
, which useserrors="backslashreplace"
.The system has
LANG=C.UTF-8
,C
, orPOSIX
. Python opens stdout and stderr witherrors="surrogateescape"
.None of
LANG/LC_*
are set. Python assumesLANG=C.UTF-8
.Python is started in UTF-8 mode with
PYTHONUTF8=1
or-X utf8
. Python opens stdout and stderr witherrors="surrogateescape"
.
Commands¶
- click.BaseCommand¶
alias of
_BaseCommand
- class click.Command(name, context_settings=None, callback=None, params=None, help=None, epilog=None, short_help=None, options_metavar='[OPTIONS]', add_help_option=True, no_args_is_help=False, hidden=False, deprecated=False)¶
Commands are the basic building block of command line interfaces in Click. A basic command handles command line parsing and might dispatch more parsing to commands nested below it.
- Parameters:
name (str | None) – the name of the command to use unless a group overrides it.
context_settings (cabc.MutableMapping[str, t.Any] | None) – an optional dictionary with defaults that are passed to the context object.
callback (t.Callable[..., t.Any] | None) – the callback to invoke. This is optional.
params (list[Parameter] | None) – the parameters to register with this command. This can be either
Option
orArgument
objects.help (str | None) – the help string to use for this command.
epilog (str | None) – like the help string but it’s printed at the end of the help page after everything else.
short_help (str | None) – the short help to use for this command. This is shown on the command listing of the parent command.
add_help_option (bool) – by default each command registers a
--help
option. This can be disabled by this parameter.no_args_is_help (bool) – this controls what happens if no arguments are provided. This option is disabled by default. If enabled this will add
--help
as argument if no arguments are passedhidden (bool) – hide this command from help outputs.
deprecated (bool) – issues a message indicating that the command is deprecated.
options_metavar (str | None) –
Changed in version 8.2: This is the base class for all commands, not
BaseCommand
.Changelog
Changed in version 8.1:
help
,epilog
, andshort_help
are stored unprocessed, all formatting is done when outputting help text, not at init, and is done even if not using the@command
decorator.Changed in version 8.0: Added a
repr
showing the command name.Changed in version 7.1: Added the
no_args_is_help
parameter.Changed in version 2.0: Added the
context_settings
parameter.- allow_extra_args = False¶
the default for the
Context.allow_extra_args
flag.
- allow_interspersed_args = True¶
the default for the
Context.allow_interspersed_args
flag.
- callback¶
the callback to execute when the command fires. This might be None in which case nothing happens.
- collect_usage_pieces(ctx)¶
Returns all the pieces that go into the usage line and returns it as a list of strings.
- context_settings: MutableMapping[str, Any]¶
an optional dictionary with defaults passed to the context.
- format_epilog(ctx, formatter)¶
Writes the epilog into the formatter if it exists.
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- format_help(ctx, formatter)¶
Writes the help into the formatter if it exists.
This is a low-level method called by
get_help()
.This calls the following methods:
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- format_help_text(ctx, formatter)¶
Writes the help text to the formatter if it exists.
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- format_options(ctx, formatter)¶
Writes all the options into the formatter if they exist.
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- format_usage(ctx, formatter)¶
Writes the usage line into the formatter.
This is a low-level method called by
get_usage()
.- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- get_help(ctx)¶
Formats the help into a string and returns it.
Calls
format_help()
internally.
- get_help_option(ctx)¶
Returns the help option object.
- get_help_option_names(ctx)¶
Returns the names for the help option.
- get_short_help_str(limit=45)¶
Gets short help for the command or makes it by shortening the long help string.
- get_usage(ctx)¶
Formats the usage line into a string and returns it.
Calls
format_usage()
internally.
- ignore_unknown_options = False¶
the default for the
Context.ignore_unknown_options
flag.
- invoke(ctx)¶
Given a context, this invokes the attached callback (if it exists) in the right way.
- main(args: Sequence[str] | None = None, prog_name: str | None = None, complete_var: str | None = None, standalone_mode: Literal[True] = True, **extra: Any) NoReturn ¶
- main(args: Sequence[str] | None = None, prog_name: str | None = None, complete_var: str | None = None, standalone_mode: bool = True, **extra: Any) Any
This is the way to invoke a script with all the bells and whistles as a command line application. This will always terminate the application after a call. If this is not wanted,
SystemExit
needs to be caught.This method is also available by directly calling the instance of a
Command
.- Parameters:
args – the arguments that should be used for parsing. If not provided,
sys.argv[1:]
is used.prog_name – the program name that should be used. By default the program name is constructed by taking the file name from
sys.argv[0]
.complete_var – the environment variable that controls the bash completion support. The default is
"_<prog_name>_COMPLETE"
with prog_name in uppercase.standalone_mode – the default behavior is to invoke the script in standalone mode. Click will then handle exceptions and convert them into error messages and the function will never return but shut down the interpreter. If this is set to False they will be propagated to the caller and the return value of this function is the return value of
invoke()
.windows_expand_args – Expand glob patterns, user dir, and env vars in command line args on Windows.
extra – extra keyword arguments are forwarded to the context constructor. See
Context
for more information.
Changelog
Changed in version 8.0.1: Added the
windows_expand_args
parameter to allow disabling command line arg expansion on Windows.Changed in version 8.0: When taking arguments from
sys.argv
on Windows, glob patterns, user dir, and env vars are expanded.Changed in version 3.0: Added the
standalone_mode
parameter.
- make_context(info_name, args, parent=None, **extra)¶
This function when given an info name and arguments will kick off the parsing and create a new
Context
. It does not invoke the actual command callback though.To quickly customize the context class used without overriding this method, set the
context_class
attribute.- Parameters:
info_name (str | None) – the info name for this invocation. Generally this is the most descriptive name for the script or command. For the toplevel script it’s usually the name of the script, for commands below it’s the name of the command.
args (list[str]) – the arguments to parse as list of strings.
parent (Context | None) – the parent context if available.
extra (Any) – extra keyword arguments forwarded to the context constructor.
- Return type:
Changelog
Changed in version 8.0: Added the
context_class
attribute.
- make_parser(ctx)¶
Creates the underlying option parser for this command.
- Parameters:
ctx (Context) –
- Return type:
_OptionParser
- name¶
the name the command thinks it has. Upon registering a command on a
Group
the group will default the command name with this information. You should instead use theContext
'sinfo_name
attribute.
- params: list[Parameter]¶
the list of parameters for this command in the order they should show up in the help page and execute. Eager parameters will automatically be handled before non eager ones.
- shell_complete(ctx, incomplete)¶
Return a list of completions for the incomplete value. Looks at the names of options and chained multi-commands.
Any command could be part of a chained multi-command, so sibling commands are valid at any point during command completion.
- Parameters:
- Return type:
Changelog
New in version 8.0.
- click.MultiCommand¶
alias of
_MultiCommand
- class click.Group(name=None, commands=None, invoke_without_command=False, no_args_is_help=None, subcommand_metavar=None, chain=False, result_callback=None, **kwargs)¶
A group is a command that nests other commands (or more groups).
- Parameters:
name (str | None) – The name of the group command.
commands (cabc.MutableMapping[str, Command] | cabc.Sequence[Command] | None) – Map names to
Command
objects. Can be a list, which will useCommand.name
as the keys.invoke_without_command (bool) – Invoke the group’s callback even if a subcommand is not given.
no_args_is_help (bool | None) – If no arguments are given, show the group’s help and exit. Defaults to the opposite of
invoke_without_command
.subcommand_metavar (str | None) – How to represent the subcommand argument in help. The default will represent whether
chain
is set or not.chain (bool) – Allow passing more than one subcommand argument. After parsing a command’s arguments, if any arguments remain another command will be matched, and so on.
result_callback (t.Callable[..., t.Any] | None) – A function to call after the group’s and subcommand’s callbacks. The value returned by the subcommand is passed. If
chain
is enabled, the value will be a list of values returned by all the commands. Ifinvoke_without_command
is enabled, the value will be the value returned by the group’s callback, or an empty list ifchain
is enabled.kwargs (t.Any) – Other arguments passed to
Command
.
Changed in version 8.2: Merged with and replaces the
MultiCommand
base class.Changelog
Changed in version 8.0: The
commands
argument can be a list of command objects.- add_command(cmd, name=None)¶
Registers another
Command
with this group. If the name is not provided, the name of the command is used.
- allow_extra_args = True¶
the default for the
Context.allow_extra_args
flag.
- allow_interspersed_args = False¶
the default for the
Context.allow_interspersed_args
flag.
- collect_usage_pieces(ctx)¶
Returns all the pieces that go into the usage line and returns it as a list of strings.
- command(__func: Callable[[...], Any]) Command ¶
- command(*args: Any, **kwargs: Any) Callable[[Callable[[...], Any]], Command]
A shortcut decorator for declaring and attaching a command to the group. This takes the same arguments as
command()
and immediately registers the created command with this group by callingadd_command()
.To customize the command class used, set the
command_class
attribute.Changelog
Changed in version 8.1: This decorator can be applied without parentheses.
Changed in version 8.0: Added the
command_class
attribute.
- command_class: type[Command] | None = None¶
If set, this is used by the group’s
command()
decorator as the defaultCommand
class. This is useful to make all subcommands use a custom command class.Changelog
New in version 8.0.
- commands: MutableMapping[str, Command]¶
The registered subcommands by their exported names.
- format_commands(ctx, formatter)¶
Extra format methods for multi methods that adds all the commands after the options.
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- format_options(ctx, formatter)¶
Writes all the options into the formatter if they exist.
- Parameters:
ctx (Context) –
formatter (HelpFormatter) –
- Return type:
None
- get_command(ctx, cmd_name)¶
Given a context and a command name, this returns a
Command
object if it exists or returnsNone
.
- group(__func: Callable[[...], Any]) Group ¶
- group(*args: Any, **kwargs: Any) Callable[[Callable[[...], Any]], Group]
A shortcut decorator for declaring and attaching a group to the group. This takes the same arguments as
group()
and immediately registers the created group with this group by callingadd_command()
.To customize the group class used, set the
group_class
attribute.Changelog
Changed in version 8.1: This decorator can be applied without parentheses.
Changed in version 8.0: Added the
group_class
attribute.
- group_class: type[Group] | type[type] | None = None¶
If set, this is used by the group’s
group()
decorator as the defaultGroup
class. This is useful to make all subgroups use a custom group class.If set to the special value
type
(literallygroup_class = type
), this group’s class will be used as the default class. This makes a custom group class continue to make custom groups.Changelog
New in version 8.0.
- invoke(ctx)¶
Given a context, this invokes the attached callback (if it exists) in the right way.
- list_commands(ctx)¶
Returns a list of subcommand names in the order they should appear.
- result_callback(replace=False)¶
Adds a result callback to the command. By default if a result callback is already registered this will chain them but this can be disabled with the replace parameter. The result callback is invoked with the return value of the subcommand (or the list of return values from all subcommands if chaining is enabled) as well as the parameters as they would be passed to the main callback.
Example:
@click.group() @click.option('-i', '--input', default=23) def cli(input): return 42 @cli.result_callback() def process_result(result, input): return result + input
- Parameters:
replace (bool) – if set to True an already existing result callback will be removed.
- Return type:
Callable[[F], F]
Changelog
Changed in version 8.0: Renamed from
resultcallback
.New in version 3.0.
- shell_complete(ctx, incomplete)¶
Return a list of completions for the incomplete value. Looks at the names of options, subcommands, and chained multi-commands.
- Parameters:
- Return type:
Changelog
New in version 8.0.
- class click.CommandCollection(name=None, sources=None, **kwargs)¶
A
Group
that looks up subcommands on other groups. If a command is not found on this group, each registered source is checked in order. Parameters on a source are not added to this group, and a source’s callback is not invoked when invoking its commands. In other words, this “flattens” commands in many groups into this one group.- Parameters:
Changed in version 8.2: This is a subclass of
Group
. Commands are looked up first on this group, then each of its sources.- add_source(group)¶
Add a group as a source of commands.
- Parameters:
group (Group) –
- Return type:
None
- get_command(ctx, cmd_name)¶
Given a context and a command name, this returns a
Command
object if it exists or returnsNone
.
- list_commands(ctx)¶
Returns a list of subcommand names in the order they should appear.
Parameters¶
- class click.Parameter(param_decls=None, type=None, required=False, default=None, callback=None, nargs=None, multiple=False, metavar=None, expose_value=True, is_eager=False, envvar=None, shell_complete=None)¶
A parameter to a command comes in two versions: they are either
Option
s orArgument
s. Other subclasses are currently not supported by design as some of the internals for parsing are intentionally not finalized.Some settings are supported by both options and arguments.
- Parameters:
param_decls (cabc.Sequence[str] | None) – the parameter declarations for this option or argument. This is a list of flags or argument names.
type (types.ParamType | t.Any | None) – the type that should be used. Either a
ParamType
or a Python type. The latter is converted into the former automatically if supported.required (bool) – controls if this is optional or not.
default (t.Any | t.Callable[[], t.Any] | None) – the default value if omitted. This can also be a callable, in which case it’s invoked when the default is needed without any arguments.
callback (t.Callable[[Context, Parameter, t.Any], t.Any] | None) – A function to further process or validate the value after type conversion. It is called as
f(ctx, param, value)
and must return the value. It is called for all sources, including prompts.nargs (int | None) – the number of arguments to match. If not
1
the return value is a tuple instead of single value. The default for nargs is1
(except if the type is a tuple, then it’s the arity of the tuple). Ifnargs=-1
, all remaining parameters are collected.metavar (str | None) – how the value is represented in the help page.
expose_value (bool) – if this is True then the value is passed onwards to the command callback and stored on the context, otherwise it’s skipped.
is_eager (bool) – eager values are processed before non eager ones. This should not be set for arguments or it will inverse the order of processing.
envvar (str | cabc.Sequence[str] | None) – a string or list of strings that are environment variables that should be checked.
shell_complete (t.Callable[[Context, Parameter, str], list[CompletionItem] | list[str]] | None) – A function that returns custom shell completions. Used instead of the param’s type completion if given. Takes
ctx, param, incomplete
and must return a list ofCompletionItem
or a list of strings.multiple (bool) –
Changelog
Changed in version 8.0:
process_value
validates required parameters and boundednargs
, and invokes the parameter callback before returning the value. This allows the callback to validate prompts.full_process_value
is removed.Changed in version 8.0:
autocompletion
is renamed toshell_complete
and has new semantics described above. The old name is deprecated and will be removed in 8.1, until then it will be wrapped to match the new requirements.Changed in version 8.0: For
multiple=True, nargs>1
, the default must be a list of tuples.Changed in version 8.0: Setting a default is no longer required for
nargs>1
, it will default toNone
.multiple=True
ornargs=-1
will default to()
.Changed in version 7.1: Empty environment variables are ignored rather than taking the empty string value. This makes it possible for scripts to clear variables if they can’t unset them.
Changed in version 2.0: Changed signature for parameter callback to also be passed the parameter. The old callback format will still work, but it will raise a warning to give you a chance to migrate the code easier.
- get_default(ctx: Context, call: Literal[True] = True) Any | None ¶
- get_default(ctx: Context, call: bool = True) Any | Callable[[], Any] | None
Get the default for the parameter. Tries
Context.lookup_default()
first, then the local default.- Parameters:
ctx – Current context.
call – If the default is a callable, call it. Disable to return the callable instead.
Changelog
Changed in version 8.0.2: Type casting is no longer performed when getting a default.
Changed in version 8.0.1: Type casting can fail in resilient parsing mode. Invalid defaults will not prevent showing help text.
Changed in version 8.0: Looks at
ctx.default_map
first.Changed in version 8.0: Added the
call
parameter.
- get_error_hint(ctx)¶
Get a stringified version of the param for use in error messages to indicate which param caused the error.
- property human_readable_name: str¶
Returns the human readable name of this parameter. This is the same as the name for options, but the metavar for arguments.
- shell_complete(ctx, incomplete)¶
Return a list of completions for the incomplete value. If a
shell_complete
function was given during init, it is used. Otherwise, thetype
shell_complete()
function is used.- Parameters:
- Return type:
Changelog
New in version 8.0.
- to_info_dict()¶
Gather information that could be useful for a tool generating user-facing documentation.
Use
click.Context.to_info_dict()
to traverse the entire CLI structure.Changelog
New in version 8.0.
- class click.Option(param_decls=None, show_default=None, prompt=False, confirmation_prompt=False, prompt_required=True, hide_input=False, is_flag=None, flag_value=None, multiple=False, count=False, allow_from_autoenv=True, type=None, help=None, hidden=False, show_choices=True, show_envvar=False, **attrs)¶
Options are usually optional values on the command line and have some extra features that arguments don’t have.
All other parameters are passed onwards to the parameter constructor.
- Parameters:
show_default (bool | str | None) – Show the default value for this option in its help text. Values are not shown by default, unless
Context.show_default
isTrue
. If this value is a string, it shows that string in parentheses instead of the actual value. This is particularly useful for dynamic options. For single option boolean flags, the default remains hidden if its value isFalse
.show_envvar (bool) – Controls if an environment variable should be shown on the help page. Normally, environment variables are not shown.
prompt (bool | str) – If set to
True
or a non empty string then the user will be prompted for input. If set toTrue
the prompt will be the option name capitalized.confirmation_prompt (bool | str) – Prompt a second time to confirm the value if it was prompted for. Can be set to a string instead of
True
to customize the message.prompt_required (bool) – If set to
False
, the user will be prompted for input only when the option was specified as a flag without a value.hide_input (bool) – If this is
True
then the input on the prompt will be hidden from the user. This is useful for password input.is_flag (bool | None) – forces this option to act as a flag. The default is auto detection.
flag_value (t.Any | None) – which value should be used for this flag if it’s enabled. This is set to a boolean automatically if the option string contains a slash to mark two options.
multiple (bool) – if this is set to True then the argument is accepted multiple times and recorded. This is similar to
nargs
in how it works but supports arbitrary number of arguments.count (bool) – this flag makes an option increment an integer.
allow_from_autoenv (bool) – if this is enabled then the value of this parameter will be pulled from an environment variable in case a prefix is defined on the context.
help (str | None) – the help string.
hidden (bool) – hide this option from help outputs.
attrs (t.Any) – Other command arguments described in
Parameter
.param_decls (cabc.Sequence[str] | None) –
type (types.ParamType | t.Any | None) –
show_choices (bool) –
Changelog
Changed in version 8.1.0: Help text indentation is cleaned here instead of only in the
@option
decorator.Changed in version 8.1.0: The
show_default
parameter overridesContext.show_default
.Changed in version 8.1.0: The default of a single option boolean flag is not shown if the default value is
False
.Changed in version 8.0.1:
type
is detected fromflag_value
if given.
Context¶
- class click.Context(command, parent=None, info_name=None, obj=None, auto_envvar_prefix=None, default_map=None, terminal_width=None, max_content_width=None, resilient_parsing=False, allow_extra_args=None, allow_interspersed_args=None, ignore_unknown_options=None, help_option_names=None, token_normalize_func=None, color=None, show_default=None)¶
The context is a special internal object that holds state relevant for the script execution at every single level. It’s normally invisible to commands unless they opt-in to getting access to it.
The context is useful as it can pass internal objects around and can control special execution features such as reading data from environment variables.
A context can be used as context manager in which case it will call
close()
on teardown.- Parameters:
command (Command) – the command class for this context.
parent (Context | None) – the parent context.
info_name (str | None) – the info name for this invocation. Generally this is the most descriptive name for the script or command. For the toplevel script it is usually the name of the script, for commands below it it’s the name of the script.
obj (t.Any | None) – an arbitrary object of user data.
auto_envvar_prefix (str | None) – the prefix to use for automatic environment variables. If this is None then reading from environment variables is disabled. This does not affect manually set environment variables which are always read.
default_map (cabc.MutableMapping[str, t.Any] | None) – a dictionary (like object) with default values for parameters.
terminal_width (int | None) – the width of the terminal. The default is inherit from parent context. If no context defines the terminal width then auto detection will be applied.
max_content_width (int | None) – the maximum width for content rendered by Click (this currently only affects help pages). This defaults to 80 characters if not overridden. In other words: even if the terminal is larger than that, Click will not format things wider than 80 characters by default. In addition to that, formatters might add some safety mapping on the right.
resilient_parsing (bool) – if this flag is enabled then Click will parse without any interactivity or callback invocation. Default values will also be ignored. This is useful for implementing things such as completion support.
allow_extra_args (bool | None) – if this is set to True then extra arguments at the end will not raise an error and will be kept on the context. The default is to inherit from the command.
allow_interspersed_args (bool | None) – if this is set to False then options and arguments cannot be mixed. The default is to inherit from the command.
ignore_unknown_options (bool | None) – instructs click to ignore options it does not know and keeps them for later processing.
help_option_names (list[str] | None) – optionally a list of strings that define how the default help parameter is named. The default is
['--help']
.token_normalize_func (t.Callable[[str], str] | None) – an optional function that is used to normalize tokens (options, choices, etc.). This for instance can be used to implement case insensitive behavior.
color (bool | None) – controls if the terminal supports ANSI colors or not. The default is autodetection. This is only needed if ANSI codes are used in texts that Click prints which is by default not the case. This for instance would affect help output.
show_default (bool | None) – Show the default value for commands. If this value is not set, it defaults to the value from the parent context.
Command.show_default
overrides this default for the specific command.
Changed in version 8.2: The
protected_args
attribute is deprecated and will be removed in Click 9.0.args
will contain remaining unparsed tokens.Changelog
Changed in version 8.1: The
show_default
parameter is overridden byCommand.show_default
, instead of the other way around.Changed in version 8.0: The
show_default
parameter defaults to the value from the parent context.Changed in version 7.1: Added the
show_default
parameter.Changed in version 4.0: Added the
color
,ignore_unknown_options
, andmax_content_width
parameters.Changed in version 3.0: Added the
allow_extra_args
andallow_interspersed_args
parameters.Changed in version 2.0: Added the
resilient_parsing
,help_option_names
, andtoken_normalize_func
parameters.- allow_extra_args¶
Indicates if the context allows extra args or if it should fail on parsing.
Changelog
New in version 3.0.
- allow_interspersed_args: bool¶
Indicates if the context allows mixing of arguments and options or not.
Changelog
New in version 3.0.
- call_on_close(f)¶
Register a function to be called when the context tears down.
This can be used to close resources opened during the script execution. Resources that support Python’s context manager protocol which would be used in a
with
statement should be registered withwith_resource()
instead.
- close()¶
Invoke all close callbacks registered with
call_on_close()
, and exit all context managers entered withwith_resource()
.- Return type:
None
- property command_path: str¶
The computed command path. This is used for the
usage
information on the help page. It’s automatically created by combining the info names of the chain of contexts to the root.
- ensure_object(object_type)¶
Like
find_object()
but sets the innermost object to a new instance of object_type if it does not exist.- Parameters:
object_type (type[V]) –
- Return type:
V
- exit(code=0)¶
Exits the application with a given exit code.
- fail(message)¶
Aborts the execution of the program with a specific error message.
- find_object(object_type)¶
Finds the closest object of a given type.
- Parameters:
object_type (type[V]) –
- Return type:
V | None
- formatter_class¶
alias of
HelpFormatter
- forward(_Context__cmd, *args, **kwargs)¶
Similar to
invoke()
but fills in default keyword arguments from the current context if the other command expects it. This cannot invoke callbacks directly, only other commands.Changelog
Changed in version 8.0: All
kwargs
are tracked inparams
so they will be passed ifforward
is called at multiple levels.
- get_help()¶
Helper method to get formatted help page for the current context and command.
- Return type:
- get_parameter_source(name)¶
Get the source of a parameter. This indicates the location from which the value of the parameter was obtained.
This can be useful for determining when a user specified a value on the command line that is the same as the default value. It will be
DEFAULT
only if the value was actually taken from the default.- Parameters:
name (str) – The name of the parameter.
- Return type:
Changelog
Changed in version 8.0: Returns
None
if the parameter was not provided from any source.
- get_usage()¶
Helper method to get formatted usage string for the current context and command.
- Return type:
- ignore_unknown_options: bool¶
Instructs click to ignore options that a command does not understand and will store it on the context for later processing. This is primarily useful for situations where you want to call into external programs. Generally this pattern is strongly discouraged because it’s not possibly to losslessly forward all arguments.
Changelog
New in version 4.0.
- info_name¶
the descriptive information name
- invoke(__callback: Callable[[...], V], *args: Any, **kwargs: Any) V ¶
- invoke(__callback: Command, *args: Any, **kwargs: Any) Any
Invokes a command callback in exactly the way it expects. There are two ways to invoke this method:
the first argument can be a callback and all other arguments and keyword arguments are forwarded directly to the function.
the first argument is a click command object. In that case all arguments are forwarded as well but proper click parameters (options and click arguments) must be keyword arguments and Click will fill in defaults.
- invoked_subcommand: str | None¶
This flag indicates if a subcommand is going to be executed. A group callback can use this information to figure out if it’s being executed directly or because the execution flow passes onwards to a subcommand. By default it’s None, but it can be the name of the subcommand to execute.
If chaining is enabled this will be set to
'*'
in case any commands are executed. It is however not possible to figure out which ones. If you require this knowledge you should use aresult_callback()
.
- lookup_default(name: str, call: Literal[True] = True) Any | None ¶
- lookup_default(name: str, call: Literal[False] = True) Any | Callable[[], Any] | None
Get the default for a parameter from
default_map
.- Parameters:
name – Name of the parameter.
call – If the default is a callable, call it. Disable to return the callable instead.
Changelog
Changed in version 8.0: Added the
call
parameter.
- make_formatter()¶
Creates the
HelpFormatter
for the help and usage output.To quickly customize the formatter class used without overriding this method, set the
formatter_class
attribute.Changelog
Changed in version 8.0: Added the
formatter_class
attribute.- Return type:
- max_content_width: int | None¶
The maximum width of formatted content (None implies a sensible default which is 80 for most things).
- property meta: dict[str, Any]¶
This is a dictionary which is shared with all the contexts that are nested. It exists so that click utilities can store some state here if they need to. It is however the responsibility of that code to manage this dictionary well.
The keys are supposed to be unique dotted strings. For instance module paths are a good choice for it. What is stored in there is irrelevant for the operation of click. However what is important is that code that places data here adheres to the general semantics of the system.
Example usage:
LANG_KEY = f'{__name__}.lang' def set_language(value): ctx = get_current_context() ctx.meta[LANG_KEY] = value def get_language(): return get_current_context().meta.get(LANG_KEY, 'en_US')
Changelog
New in version 5.0.
- params: dict[str, Any]¶
Map of parameter names to their parsed values. Parameters with
expose_value=False
are not stored.
- parent¶
the parent context or None if none exists.
- resilient_parsing: bool¶
Indicates if resilient parsing is enabled. In that case Click will do its best to not cause any failures and default values will be ignored. Useful for completion.
- scope(cleanup=True)¶
This helper method can be used with the context object to promote it to the current thread local (see
get_current_context()
). The default behavior of this is to invoke the cleanup functions which can be disabled by setting cleanup to False. The cleanup functions are typically used for things such as closing file handles.If the cleanup is intended the context object can also be directly used as a context manager.
Example usage:
with ctx.scope(): assert get_current_context() is ctx
This is equivalent:
with ctx: assert get_current_context() is ctx
Changelog
New in version 5.0.
- Parameters:
cleanup (bool) – controls if the cleanup functions should be run or not. The default is to run these functions. In some situations the context only wants to be temporarily pushed in which case this can be disabled. Nested pushes automatically defer the cleanup.
- Return type:
- set_parameter_source(name, source)¶
Set the source of a parameter. This indicates the location from which the value of the parameter was obtained.
- Parameters:
name (str) – The name of the parameter.
source (ParameterSource) – A member of
ParameterSource
.
- Return type:
None
- to_info_dict()¶
Gather information that could be useful for a tool generating user-facing documentation. This traverses the entire CLI structure.
with Context(cli) as ctx: info = ctx.to_info_dict()
Changelog
New in version 8.0.
- token_normalize_func: Callable[[str], str] | None¶
An optional normalization function for tokens. This is options, choices, commands etc.
- with_resource(context_manager)¶
Register a resource as if it were used in a
with
statement. The resource will be cleaned up when the context is popped.Uses
contextlib.ExitStack.enter_context()
. It calls the resource’s__enter__()
method and returns the result. When the context is popped, it closes the stack, which calls the resource’s__exit__()
method.To register a cleanup function for something that isn’t a context manager, use
call_on_close()
. Or use something fromcontextlib
to turn it into a context manager first.@click.group() @click.option("--name") @click.pass_context def cli(ctx): ctx.obj = ctx.with_resource(connect_db(name))
- Parameters:
context_manager (AbstractContextManager[V]) – The context manager to enter.
- Returns:
Whatever
context_manager.__enter__()
returns.- Return type:
V
Changelog
New in version 8.0.
- click.get_current_context(silent: Literal[False] = False) Context ¶
- click.get_current_context(silent: bool = False) Context | None
Returns the current click context. This can be used as a way to access the current context object from anywhere. This is a more implicit alternative to the
pass_context()
decorator. This function is primarily useful for helpers such asecho()
which might be interested in changing its behavior based on the current context.To push the current context,
Context.scope()
can be used.Changelog
New in version 5.0.
- Parameters:
silent – if set to True the return value is None if no context is available. The default behavior is to raise a
RuntimeError
.
- class click.core.ParameterSource(value)¶
This is an
Enum
that indicates the source of a parameter’s value.Use
click.Context.get_parameter_source()
to get the source for a parameter by name.Changelog
Changed in version 8.0: Use
Enum
and drop thevalidate
method.Changed in version 8.0: Added the
PROMPT
value.- COMMANDLINE = 1¶
The value was provided by the command line args.
- ENVIRONMENT = 2¶
The value was provided with an environment variable.
- DEFAULT = 3¶
Used the default specified by the parameter.
- DEFAULT_MAP = 4¶
Used a default provided by
Context.default_map
.
- PROMPT = 5¶
Used a prompt to confirm a default or provide a value.
Types¶
- click.STRING = STRING¶
- click.INT = INT¶
- click.FLOAT = FLOAT¶
- click.BOOL = BOOL¶
- click.UUID = UUID¶
- click.UNPROCESSED = UNPROCESSED¶
- class click.File(mode='r', encoding=None, errors='strict', lazy=None, atomic=False)¶
Declares a parameter to be a file for reading or writing. The file is automatically closed once the context tears down (after the command finished working).
Files can be opened for reading or writing. The special value
-
indicates stdin or stdout depending on the mode.By default, the file is opened for reading text data, but it can also be opened in binary mode or for writing. The encoding parameter can be used to force a specific encoding.
The lazy flag controls if the file should be opened immediately or upon first IO. The default is to be non-lazy for standard input and output streams as well as files opened for reading, lazy otherwise. When opening a file lazily for reading, it is still opened temporarily for validation, but will not be held open until first IO. lazy is mainly useful when opening for writing to avoid creating the file until it is needed.
Starting with Click 2.0, files can also be opened atomically in which case all writes go into a separate file in the same folder and upon completion the file will be moved over to the original location. This is useful if a file regularly read by other users is modified.
See File Arguments for more information.
- class click.Path(exists=False, file_okay=True, dir_okay=True, writable=False, readable=True, resolve_path=False, allow_dash=False, path_type=None, executable=False)¶
The
Path
type is similar to theFile
type, but returns the filename instead of an open file. Various checks can be enabled to validate the type of file and permissions.- Parameters:
exists (bool) – The file or directory needs to exist for the value to be valid. If this is not set to
True
, and the file does not exist, then all further checks are silently skipped.file_okay (bool) – Allow a file as a value.
dir_okay (bool) – Allow a directory as a value.
readable (bool) – if true, a readable check is performed.
writable (bool) – if true, a writable check is performed.
executable (bool) – if true, an executable check is performed.
resolve_path (bool) – Make the value absolute and resolve any symlinks. A
~
is not expanded, as this is supposed to be done by the shell only.allow_dash (bool) – Allow a single dash as a value, which indicates a standard stream (but does not open it). Use
open_file()
to handle opening this value.path_type (type[t.Any] | None) – Convert the incoming path value to this type. If
None
, keep Python’s default, which isstr
. Useful to convert topathlib.Path
.
Changelog
Changed in version 8.1: Added the
executable
parameter.Changed in version 8.0: Allow passing
path_type=pathlib.Path
.Changed in version 6.0: Added the
allow_dash
parameter.
- class click.Choice(choices, case_sensitive=True)¶
The choice type allows a value to be checked against a fixed set of supported values. All of these values have to be strings.
You should only pass a list or tuple of choices. Other iterables (like generators) may lead to surprising results.
The resulting value will always be one of the originally passed choices regardless of
case_sensitive
or anyctx.token_normalize_func
being specified.See Choice Options for an example.
- class click.IntRange(min=None, max=None, min_open=False, max_open=False, clamp=False)¶
Restrict an
click.INT
value to a range of accepted values. See Range Options.If
min
ormax
are not passed, any value is accepted in that direction. Ifmin_open
ormax_open
are enabled, the corresponding boundary is not included in the range.If
clamp
is enabled, a value outside the range is clamped to the boundary instead of failing.Changelog
Changed in version 8.0: Added the
min_open
andmax_open
parameters.
- class click.FloatRange(min=None, max=None, min_open=False, max_open=False, clamp=False)¶
Restrict a
click.FLOAT
value to a range of accepted values. See Range Options.If
min
ormax
are not passed, any value is accepted in that direction. Ifmin_open
ormax_open
are enabled, the corresponding boundary is not included in the range.If
clamp
is enabled, a value outside the range is clamped to the boundary instead of failing. This is not supported if either boundary is markedopen
.Changelog
Changed in version 8.0: Added the
min_open
andmax_open
parameters.
- class click.DateTime(formats=None)¶
The DateTime type converts date strings into datetime objects.
The format strings which are checked are configurable, but default to some common (non-timezone aware) ISO 8601 formats.
When specifying DateTime formats, you should only pass a list or a tuple. Other iterables, like generators, may lead to surprising results.
The format strings are processed using
datetime.strptime
, and this consequently defines the format strings which are allowed.Parsing is tried using each format, in order, and the first format which parses successfully is used.
- Parameters:
formats (cabc.Sequence[str] | None) – A list or tuple of date format strings, in the order in which they should be tried. Defaults to
'%Y-%m-%d'
,'%Y-%m-%dT%H:%M:%S'
,'%Y-%m-%d %H:%M:%S'
.
- class click.Tuple(types)¶
The default behavior of Click is to apply a type on a value directly. This works well in most cases, except for when nargs is set to a fixed count and different types should be used for different items. In this case the
Tuple
type can be used. This type can only be used if nargs is set to a fixed number.For more information see Tuples as Multi Value Options.
This can be selected by using a Python tuple literal as a type.
- class click.ParamType¶
Represents the type of a parameter. Validates and converts values from the command line or Python into the correct type.
To implement a custom type, subclass and implement at least the following:
The
name
class attribute must be set.Calling an instance of the type with
None
must returnNone
. This is already implemented by default.convert()
must convert string values to the correct type.convert()
must accept values that are already the correct type.It must be able to convert a value if the
ctx
andparam
arguments areNone
. This can occur when converting prompt input.
- convert(value, param, ctx)¶
Convert the value to the correct type. This is not called if the value is
None
(the missing value).This must accept string values from the command line, as well as values that are already the correct type. It may also convert other compatible types.
The
param
andctx
arguments may beNone
in certain situations, such as when converting prompt input.If the value cannot be converted, call
fail()
with a descriptive message.
- envvar_list_splitter: ClassVar[str | None] = None¶
if a list of this type is expected and the value is pulled from a string environment variable, this is what splits it up. None means any whitespace. For all parameters the general rule is that whitespace splits them up. The exception are paths and files which are split by
os.path.pathsep
by default (“:” on Unix and “;” on Windows).
- fail(message, param=None, ctx=None)¶
Helper method to fail with an invalid value message.
- get_metavar(param)¶
Returns the metavar default for this param if it provides one.
- get_missing_message(param)¶
Optionally might return extra information about a missing parameter.
Changelog
New in version 2.0.
- shell_complete(ctx, param, incomplete)¶
Return a list of
CompletionItem
objects for the incomplete value. Most types do not provide completions, but some do, and this allows custom types to provide custom completions as well.- Parameters:
- Return type:
Changelog
New in version 8.0.
- split_envvar_value(rv)¶
Given a value from an environment variable this splits it up into small chunks depending on the defined envvar list splitter.
If the splitter is set to None, which means that whitespace splits, then leading and trailing whitespace is ignored. Otherwise, leading and trailing splitters usually lead to empty items being included.
- to_info_dict()¶
Gather information that could be useful for a tool generating user-facing documentation.
Use
click.Context.to_info_dict()
to traverse the entire CLI structure.Changelog
New in version 8.0.
Exceptions¶
- exception click.ClickException(message)¶
An exception that Click can handle and show to the user.
- Parameters:
message (str) –
- Return type:
None
- exception click.Abort¶
An internal signalling exception that signals Click to abort.
- exception click.UsageError(message, ctx=None)¶
An internal exception that signals a usage error. This typically aborts any further handling.
- exception click.BadParameter(message, ctx=None, param=None, param_hint=None)¶
An exception that formats out a standardized error message for a bad parameter. This is useful when thrown from a callback or type as Click will attach contextual information to it (for instance, which parameter it is).
Changelog
New in version 2.0.
- Parameters:
param (Parameter | None) – the parameter object that caused this error. This can be left out, and Click will attach this info itself if possible.
param_hint (str | None) – a string that shows up as parameter name. This can be used as alternative to param in cases where custom validation should happen. If it is a string it’s used as such, if it’s a list then each item is quoted and separated.
message (str) –
ctx (Context | None) –
- Return type:
None
- exception click.FileError(filename, hint=None)¶
Raised if a file cannot be opened.
- exception click.NoSuchOption(option_name, message=None, possibilities=None, ctx=None)¶
Raised if click attempted to handle an option that does not exist.
Changelog
New in version 4.0.
- exception click.BadOptionUsage(option_name, message, ctx=None)¶
Raised if an option is generally supplied but the use of the option was incorrect. This is for instance raised if the number of arguments for an option is not correct.
Changelog
New in version 4.0.
- exception click.BadArgumentUsage(message, ctx=None)¶
Raised if an argument is generally supplied but the use of the argument was incorrect. This is for instance raised if the number of values for an argument is not correct.
Changelog
New in version 6.0.
Formatting¶
- class click.HelpFormatter(indent_increment=2, width=None, max_width=None)¶
This class helps with formatting text-based help pages. It’s usually just needed for very special internal cases, but it’s also exposed so that developers can write their own fancy outputs.
At present, it always writes into memory.
- Parameters:
- dedent()¶
Decreases the indentation.
- Return type:
None
- indent()¶
Increases the indentation.
- Return type:
None
- section(name)¶
Helpful context manager that writes a paragraph, a heading, and the indents.
- write(string)¶
Writes a unicode string into the internal buffer.
- Parameters:
string (str) –
- Return type:
None
- write_dl(rows, col_max=30, col_spacing=2)¶
Writes a definition list into the buffer. This is how options and commands are usually formatted.
- write_heading(heading)¶
Writes a heading into the buffer.
- Parameters:
heading (str) –
- Return type:
None
- write_paragraph()¶
Writes a paragraph into the buffer.
- Return type:
None
- click.wrap_text(text, width=78, initial_indent='', subsequent_indent='', preserve_paragraphs=False)¶
A helper function that intelligently wraps text. By default, it assumes that it operates on a single paragraph of text but if the preserve_paragraphs parameter is provided it will intelligently handle paragraphs (defined by two empty lines).
If paragraphs are handled, a paragraph can be prefixed with an empty line containing the
\b
character (\x08
) to indicate that no rewrapping should happen in that block.- Parameters:
text (str) – the text that should be rewrapped.
width (int) – the maximum width for the text.
initial_indent (str) – the initial indent that should be placed on the first line as a string.
subsequent_indent (str) – the indent string that should be placed on each consecutive line.
preserve_paragraphs (bool) – if this flag is set then the wrapping will intelligently handle paragraphs.
- Return type:
Parsing¶
- click.OptionParser¶
alias of
_OptionParser
Shell Completion¶
See Shell Completion for information about enabling and customizing Click’s shell completion system.
- class click.shell_completion.CompletionItem(value, type='plain', help=None, **kwargs)¶
Represents a completion value and metadata about the value. The default metadata is
type
to indicate special shell handling, andhelp
if a shell supports showing a help string next to the value.Arbitrary parameters can be passed when creating the object, and accessed using
item.attr
. If an attribute wasn’t passed, accessing it returnsNone
.- Parameters:
value (t.Any) – The completion suggestion.
type (str) – Tells the shell script to provide special completion support for the type. Click uses
"dir"
and"file"
.help (str | None) – String shown next to the value if supported.
kwargs (t.Any) – Arbitrary metadata. The built-in implementations don’t use this, but custom type completions paired with custom shell support could use it.
- class click.shell_completion.ShellComplete(cli, ctx_args, prog_name, complete_var)¶
Base class for providing shell completion support. A subclass for a given shell will override attributes and methods to implement the completion instructions (
source
andcomplete
).- Parameters:
Changelog
New in version 8.0.
- name: ClassVar[str]¶
Name to register the shell as with
add_completion_class()
. This is used in completion instructions ({name}_source
and{name}_complete
).
- source_template: ClassVar[str]¶
Completion script template formatted by
source()
. This must be provided by subclasses.
- source_vars()¶
Vars for formatting
source_template
.By default this provides
complete_func
,complete_var
, andprog_name
.
- source()¶
Produce the shell script that defines the completion function. By default this
%
-style formatssource_template
with the dict returned bysource_vars()
.- Return type:
- get_completion_args()¶
Use the env vars defined by the shell script to return a tuple of
args, incomplete
. This must be implemented by subclasses.
- get_completions(args, incomplete)¶
Determine the context and last complete command or parameter from the complete args. Call that object’s
shell_complete
method to get the completions for the incomplete value.- Parameters:
- Return type:
- format_completion(item)¶
Format a completion item into the form recognized by the shell script. This must be implemented by subclasses.
- Parameters:
item (CompletionItem) – Completion item to format.
- Return type:
- complete()¶
Produce the completion data to send back to the shell.
By default this calls
get_completion_args()
, gets the completions, then callsformat_completion()
for each completion.- Return type:
- click.shell_completion.add_completion_class(cls, name=None)¶
Register a
ShellComplete
subclass under the given name. The name will be provided by the completion instruction environment variable during completion.- Parameters:
cls (ShellCompleteType) – The completion class that will handle completion for the shell.
name (str | None) – Name to register the class under. Defaults to the class’s
name
attribute.
- Return type:
ShellCompleteType
Testing¶
- class click.testing.CliRunner(charset='utf-8', env=None, echo_stdin=False, mix_stderr=True)¶
The CLI runner provides functionality to invoke a Click command line script for unittesting purposes in a isolated environment. This only works in single-threaded systems without any concurrency as it changes the global interpreter state.
- Parameters:
charset (str) – the character set for the input and output data.
env (cabc.Mapping[str, str | None] | None) – a dictionary with environment variables for overriding.
echo_stdin (bool) – if this is set to True, then reading from stdin writes to stdout. This is useful for showing examples in some circumstances. Note that regular prompts will automatically echo the input.
mix_stderr (bool) – if this is set to False, then stdout and stderr are preserved as independent streams. This is useful for Unix-philosophy apps that have predictable stdout and noisy stderr, such that each may be measured independently
- get_default_prog_name(cli)¶
Given a command object it will return the default program name for it. The default is the name attribute or
"root"
if not set.
- invoke(cli, args=None, input=None, env=None, catch_exceptions=True, color=False, **extra)¶
Invokes a command in an isolated environment. The arguments are forwarded directly to the command line script, the extra keyword arguments are passed to the
main()
function of the command.This returns a
Result
object.- Parameters:
cli (Command) – the command to invoke
args (str | cabc.Sequence[str] | None) – the arguments to invoke. It may be given as an iterable or a string. When given as string it will be interpreted as a Unix shell command. More details at
shlex.split()
.input (str | bytes | t.IO[t.Any] | None) – the input data for sys.stdin.
env (cabc.Mapping[str, str | None] | None) – the environment overrides.
catch_exceptions (bool) – Whether to catch any other exceptions than
SystemExit
.extra (t.Any) – the keyword arguments to pass to
main()
.color (bool) – whether the output should contain color codes. The application can still override this explicitly.
- Return type:
Changelog
Changed in version 8.0: The result object has the
return_value
attribute with the value returned from the invoked command.Changed in version 4.0: Added the
color
parameter.Changed in version 3.0: Added the
catch_exceptions
parameter.Changed in version 3.0: The result object has the
exc_info
attribute with the traceback if available.
- isolated_filesystem(temp_dir=None)¶
A context manager that creates a temporary directory and changes the current working directory to it. This isolates tests that affect the contents of the CWD to prevent them from interfering with each other.
- Parameters:
temp_dir (str | PathLike[str] | None) – Create the temporary directory under this directory. If given, the created directory is not removed when exiting.
- Return type:
Changelog
Changed in version 8.0: Added the
temp_dir
parameter.
- isolation(input=None, env=None, color=False)¶
A context manager that sets up the isolation for invoking of a command line tool. This sets up stdin with the given input data and os.environ with the overrides from the given dictionary. This also rebinds some internals in Click to be mocked (like the prompt functionality).
This is automatically done in the
invoke()
method.- Parameters:
- Return type:
Changelog
Changed in version 8.0:
stderr
is opened witherrors="backslashreplace"
instead of the default"strict"
.Changed in version 4.0: Added the
color
parameter.
- class click.testing.Result(runner, stdout_bytes, stderr_bytes, return_value, exit_code, exception, exc_info=None)¶
Holds the captured result of an invoked CLI script.
- Parameters:
runner (CliRunner) –
stdout_bytes (bytes) –
stderr_bytes (bytes | None) –
return_value (t.Any) –
exit_code (int) –
exception (BaseException | None) –
exc_info (tuple[type[BaseException], BaseException, TracebackType] | None) –
- exc_info¶
The traceback
- exception¶
The exception that happened if one did.
- exit_code¶
The exit code as integer.
- return_value¶
The value returned from the invoked command.
Changelog
New in version 8.0.
- runner¶
The runner that created the result
- stderr_bytes¶
The standard error as bytes, or None if not available
- stdout_bytes¶
The standard output as bytes.