poethepoet 0.11.0

A task runner that works well with poetry.

A task runner that works well with poetry.

Features

✅  Straight forward declaration of project tasks in your pyproject.toml (kind of like npm scripts)

✅  Task are run in poetry’s virtualenv (or another env you specify)

✅  Shell completion of task names (and global options too for zsh)

✅  Tasks can be commands (with or without a shell) or references to python functions (like tool.poetry.scripts)

✅  Short and sweet commands with extra arguments passed to the task poe [options] task [task_args]

✅  Tasks can specify and reference environment variables as if they were evaluated by a shell

✅  Tasks are self documenting, with optional help messages (just run poe without arguments)

✅  Tasks can be defined as a sequence of other tasks

✅  Works with .env files

Installation

Into your project (so it works inside poetry shell):

poetry add --dev poethepoet

And into any python environment (so it works outside of poetry shell)

pip install poethepoet

Enable tab completion for your shell

Poe comes with tab completion scripts for bash, zsh, and fish to save you keystrokes. How to install them will depend on your shell setup.

Zsh

# oh-my-zsh
mkdir -p ~/.oh-my-zsh/completions
poe _zsh_completion > ~/.oh-my-zsh/completions/_poe

# without oh-my-zsh
mkdir -p ~/.zfunc/
poe _zsh_completion > ~/.zfunc/_poetry

Note that you’ll need to start a new shell for the new completion script to be loaded. If it still doesn’t work try adding a call to compinit to the end of your zshrc file.

Bash

# System bash
poe _bash_completion > /etc/bash_completion.d/poe.bash-completion

# Homebrew bash
poe _bash_completion > $(brew --prefix)/etc/bash_completion.d/poe.bash-completion

How to ensure installed bash completions are enabled may vary depending on your system.

Fish

# Fish
poe _fish_completion > ~/.config/fish/completions/poe.fish

# Homebrew fish
poe _fish_completion > (brew --prefix)/share/fish/vendor_completions.d/poe.fish

Basic Usage

Define tasks in your pyproject.toml

See a real example

[tool.poe.tasks]
test   = "pytest --cov=poethepoet"                                # simple command based task
serve  = { script = "my_app.service:run(debug=True)" }            # python script based task
tunnel = { shell = "ssh -N -L 0.0.0.0:8080:$PROD:8080 $PROD &" }  # (posix) shell based task

Run tasks with the poe cli

poe test

By default additional arguments are passed to the task so

poe test -v tests/favorite_test.py

results in the following being run inside poetry’s virtualenv

pytest --cov=poethepoet -v tests/favorite_test.py

You can also run it like so if you fancy

python -m poethepoet [options] task [task_args]

Or install it as a dev dependency with poetry and run it like

poetry add --dev poethepoet
poetry run poe [options] task [task_args]

Though it that case you might like to do alias poe='poetry run poe'.

Types of task

There are four types of task: simple commands (cmd), python scripts (script), shell scripts (shell), and sequence tasks (sequence).

• Command tasks contain a single command that will be executed without a shell. This covers most basic use cases for example:

  [tool.poe.tasks]
  format = "black ."  # strings are interpreted as commands by default
  clean = """
  # Multiline commands including comments work too. Unescaped whitespace is ignored.
  rm -rf .coverage
         .mypy_cache
         .pytest_cache
         dist
         ./**/__pycache__
  """
  lint = { "cmd": "pylint poethepoet" }  # Inline tables with a cmd key work too
  greet = "echo Hello $USER"  # Environment variables work, even though there's no shell!

• Script tasks contain a reference to a python callable to import and execute, for example:

  [tool.poe.tasks]
  fetch-assets = { "script" = "my_package.assets:fetch" }
  fetch-images = { "script" = "my_package.assets:fetch(only='images', log=environ['LOG_PATH'])" }

  As in the second example, is it possible to hard code literal arguments to the target callable. In fact a subset of python syntax, operators, and globals can be used inline to define the arguments to the function using normal python syntax, including environ (from the os package) to access environment variables that are available to the task.

  If extra arguments are passed to task on the command line (and no CLI args are declared), then they will be available within the called python function via sys.argv.

• Shell tasks are similar to simple command tasks except that they are executed inside a new shell, and can consist of multiple separate commands, command substitution, pipes, background processes, etc.

  An example use case for this might be opening some ssh tunnels in the background with one task and closing them with another like so:

  [tool.poe.tasks]
  pfwd = { "shell" = "ssh -N -L 0.0.0.0:8080:$STAGING:8080 $STAGING & ssh -N -L 0.0.0.0:5432:$STAGINGDB:5432 $STAGINGDB &" }
  pfwdstop = { "shell" = "kill $(pgrep -f "ssh -N -L .*:(8080|5432)")" }

• Composite tasks are defined as a sequence of other tasks as an array.

  By default the contents of the array are interpreted as references to other tasks (actually a ref task type), though this behaviour can be altered by setting the global default_array_item_task_type option to the name of another task type such as cmd, or by setting the default_item_type option locally on the sequence task.

  An example task with references

  [tool.poe.tasks]
  
  test = "pytest --cov=src"
  build = "poetry build"
  _publish = "poetry publish"
  release = ["test", "build", "_publish"]

  Note that tasks with names prefixed with _ are not included in the documentation or directly executable, but can be useful for cases where a task is only needed for referencing from another task.

  An example task with inline tasks expressed via inline tables

  release = [
    { cmd = "pytest --cov=src" },
    { script = "devtasks:build" },
    { ref = "_publish" },
  ]

  An example task with inline tasks expressed via an array of tables

  [tool.poe.tasks]
  
    [[tool.poe.tasks.release]]
    cmd = "pytest --cov=src"
  
    [[tool.poe.tasks.release]]
    script = "devtasks:build"
  
    [[tool.poe.tasks.release]]
    ref = "_publish"

  An example task with inline script subtasks using default_item_type

  release.sequence = [
    "devtasks:run_tests(all=True)",
    "devtasks:build",
    "devtasks:publish",
  ]
  release.default_item_type = "script"

  A failure (non-zero result) will result in the rest of the tasks in the sequence not being executed, unless the ignore_fail option is set on the task to true or "return_zero" like so:

  [tool.poe.tasks]
  attempts.sequence = ["task1", "task2", "task3"]
  attempts.ignore_fail = "return_zero"

  If you want to run all the subtasks in the sequence but return non-zero result in the end of the sequence if any of the subtasks have failed you can set ignore_fail option to the return_non_zero value like so:

  [tool.poe.tasks]
  attempts.sequence = ["task1", "task2", "task3"]
  attempts.ignore_fail = "return_non_zero"

Task level configuration

Task help text

You can specify help text to be shown alongside the task name in the list of available tasks (such as when executing poe with no arguments), by adding a help key like so:

[tool.poe.tasks]
style = {cmd = "black . --check --diff", help = "Check code style"}

Environment variables

You can specify arbitrary environment variables to be set for a task by providing the env key like so:

[tool.poe.tasks]
serve.script = "myapp:run"
serve.env = { PORT = "9001" }

Notice this example uses deep keys which can be more convenient but aren’t as well supported by some toml implementations.

The above example can be modified to only set the PORT variable if it is not already set by replacing the last line with the following:

serve.env.PORT.default = "9001"

You can also specify an env file (with bash-like syntax) to load per task like so:

# .env
STAGE=dev
PASSWORD='!@#$%^&*('

[tool.poe.tasks]
serve.script  = "myapp:run"
serve.envfile = ".env"

Declaring CLI arguments

By default extra arguments passed to the poe CLI following the task name are appended to the end of a cmd task, or exposed as sys.argv in a script task (but will cause an error for shell or sequence tasks). Alternatively it is possible to define named arguments that a task should accept, which will be documented in the help for that task, and exposed to the task in a way the makes the most sense for that task type.

In general named arguments can take one of the following three forms:

• positional arguments which are provided directly following the name of the task like

  poe task-name arg-value

• option arguments which are provided like

  poe task-name --option-name arg-value

• flags which are either provided or not, but don’t accept a value like

  poe task-name --flag

The value for the named argument is then accessible by name within the task content, though exactly how will depend on the type of the task as detailed below.

Configuration syntax

Named arguments are configured by declaring the args task option as either an array or a subtable.

Array configuration syntax

The array form may contain string items which are interpreted as an option argument with the given name.

[tool.poe.tasks.serve]
cmd = "myapp:run"
args = ["host", "port"]

This example can be invoked as

poe serve --host 0.0.0.0 --port 8001

Items in the array can also be inline tables to allow for more configuration to be provided to the task like so:

[tool.poe.tasks.serve]
cmd = "myapp:run"
args = [{ name = "host", default = "localhost" }, { name = "port", default = "9000" }]

You can also use the toml syntax for an array of tables like so:

[tool.poe.tasks.serve]
cmd = "myapp:run"
help = "Run the application server"

  [[tool.poe.tasks.serve.args]]
  name = "host"
  options = ["-h", "--host"]
  help = "The host on which to expose the service"
  default = "localhost"

  [[tool.poe.tasks.serve.args]]
  name = "port"
  options = ["-p", "--port"]
  help = "The port on which to expose the service"
  default = "8000"

Table configuration syntax

You can also use the toml syntax for subtables like so:

[tool.poe.tasks.serve]
cmd = "myapp:run"
help = "Run the application server"

  [tool.poe.tasks.serve.args.host]
  options = ["-h", "--host"]
  help = "The host on which to expose the service"
  default = "localhost"

  [tool.poe.tasks.serve.args.port]
  options = ["-p", "--port"]
  help = "The port on which to expose the service"
  default = "8000"

When using this form the name option is no longer applicable because the key for the argument within the args table is taken as the name.

Task argument options

Named arguments support the following configuration options:

• defaultUnion[str, int, float, bool]

  The value to use if the argument is not provided. This option has no effect if the required option is set to true.

• helpstr

  A short description of the argument to include in the documentation of the task.

• namestr

  The name of the task. Only applicable when args is an array.

• optionsList[str]

  A list of options to accept for this argument, similar to argsparse name or flags. If not provided then the name of the argument is used. You can use this option to expose a different name to the CLI vs the name that is used inside the task, or to specify long and short forms of the CLI option, e.g. [“-h”, “–help”].

• positionalbool

  If set to true then the argument becomes a position argument instead of an option argument. Note that positional arguments may not have type bool.

• requiredbool

  If true then not providing the argument will result in an error. Arguments are not required by default.

• typestr

  The type that the provided value will be cast to. The set of acceptable options is {“string”, “float”, “integer”, “boolean”}. If not provided then the default behaviour is to keep values as strings. Setting the type to “bool” makes the resulting argument a flag that if provided will set the value to the boolean opposite of the default value – i.e. true if no default value is given, or false if default = true.

Arguments for cmd and shell tasks

For cmd and shell tasks the values are exposed to the task as environment variables. For example given the following configuration:

[tool.poe.tasks.passby]
shell = """
echo "hello $planet";
echo "goodbye $planet";
"""
help = "Pass by a planet!"

  [[tool.poe.tasks.passby.args]]
  name = "planet"
  help = "Name of the planet to pass"
  default = "earth"
  options = ["-p", "--planet"]

The resulting task can be run like:

poe passby --planet mars

Arguments for script tasks

Arguments can be defined for script tasks in the same way, but how they are exposed to the underlying python function depends on how the script is defined.

In the following example, since no parenthesis are included for the referenced function, all provided args will be passed to the function as kwargs:

[tool.poe.tasks]
build = { script = "project.util:build", args = ["dest", "version"] }

You can also control exactly how values are passed to the python function as demonstrated in the following example:

[tool.poe.tasks]
build = { script = "project.util:build(dest, build_version=version, verbose=True)", args = ["dest", "version"]

Arguments for sequence tasks

Arguments can be passed to the tasks referenced from a sequence task as in the following example.

[tool.poe.tasks]
build = { script = "util:build_app", args = [{ name = "target", positional = true }] }

[tool.poe.tasks.check]
sequence = ["build ${target}", { script = "util:run_tests(environ['target'])" }]
args = ["target"]

This works by setting the argument values as environment variables for the subtasks, which can be read at runtime, but also referenced in the task definition as demonstrated in the above example for a ref task and script task.

Project-wide configuration options

Global environment variables

You can configure environment variables to be set for all poe tasks in the pyproject.toml file by specifying tool.poe.env like so

[tool.poe.env]
VAR1 = "FOO"
VAR2 = "BAR"

As for the task level option, you can indicated that a variable should only be set if not already set like so:

[tool.poe.env]
VAR1.default = "FOO"

You can also specify an env file (with bash-like syntax) to load for all tasks like so:

# .env
STAGE=dev
PASSWORD='!@#$%^&*('

[tool.poe]
envfile = ".env"

Default command verbosity

You can alter the verbosity level for poe commands by passing --quiet / -q (which decreases verbosity) or --verbose / -v (which increases verbosity) on the CLI.

If you want to change the default verbosity level for all commands, you can use the tool.poe.verbose option in pyproject.toml like so:

[tool.poe]
verbosity = -1

-1 is the quietest and 1 is the most verbose. 0 is the default.

Note that the command line arguments are incremental: -q subtracts one from the default verbosity, and -v adds one. So setting the default verbosity to -1 and passing -v -v on the command line is equivalent to setting the verbosity to 0 and just passing -v.

Run poe from anywhere

By default poe will detect when you’re inside a project with a pyproject.toml in the root. However if you want to run it from elsewhere then that is supported by using the --root option to specify an alternate location for the toml file. The task will run with the given location as the current working directory.

In all cases the path to project root (where the pyproject.toml resides) will be available as $POE_ROOT within the command line and process.

Change the default task type

By default tasks defined as strings are interpreted as shell commands, and script tasks require the more verbose table syntax to specify. For example:

my_cmd_task = "cmd args"
my_script_task = { "script" = "my_package.my_module:run" }

This behaviour can be reversed by setting the default_task_type option in your pyproject.toml like so:

[tool.poe]
default_task_type = "script"

[tool.poe.tasks]
my_cmd_task = { "cmd" = "cmd args" }
my_script_task = "my_package.my_module:run"

Change the executor type

You can configure poe to use a specific executor by setting tool.poe.executor.type. Valid values include:

• auto: to automatically use the most appropriate of the following executors in order

• poetry: to run tasks in the poetry managed environment

• virtualenv: to run tasks in the indicated virtualenv (or else “./.venv” if present)

• simple: to run tasks without doing any specific environment setup

The default behaviour is auto.

For example the following configuration will cause poe to ignore the poetry environment (if present), and instead use the virtualenv at the given location relative to the parent directory.

[tool.poe.executor]
type = "virtualenv"
location = "myvenv"

See below for more details.

Usage without poetry

Poe the Poet was originally intended for use alongside poetry. But it works just as well with any other kind of virtualenv, or standalone. This behaviour is configurable via the tool.poe.executor global option (see above).

By default poe will run tasks in the poetry managed environment, if the pyproject.toml contains a tool.poetry section. If it doesn’t then poe looks for a virtualenv to use from ./.venv or ./venv relative to the pyproject.toml file. Otherwise it falls back to running tasks without any special environment management.

Composing tasks into graphs (Experimental)

You can define tasks that depend on other tasks, and optionally capture and reuse the output of those tasks, thus defining an execution graph of tasks. This is done by using the deps task option, or if you want to capture the output of the upstream task to pass it to the present task then specify the uses option, as demonstrated below.

[tool.poe.tasks]
_website_bucket_name.shell = """
  aws cloudformation describe-stacks \
    --stack-name $AWS_SAM_STACK_NAME \
    --query "Stacks[0].Outputs[?(@.OutputKey == 'FrontendS3Bucket')].OutputValue" \
  | jq -cr 'select(0)[0]'
"""

[tool.poe.tasks.build-backend]
help = "Build the backend"
sequence = [
  {cmd = "poetry export -f requirements.txt --output src/requirements.txt"},
  {cmd = "sam build"},
]

[tool.poe.tasks.build-frontend]
help = "Build the frontend"
cmd = "npm --prefix client run build"

[tool.poe.tasks.shipit]
help = "Build and deploy the app"
sequence = [
  "sam deploy --config-env $SAM_ENV_NAME",
  "aws s3 sync --delete ./client/build s3://${BUCKET_NAME}"
]
default_item_type = "cmd"
deps = ["build-frontend", "build-backend"]
uses = { BUCKET_NAME = "_website_bucket_name" }

In this example the shipit task depends on the build-frontend build-backend, which means that these tasks get executed before the shipit task. It also declares that it uses the output of the hidden _website_bucket_name task, which means that this also gets executed, but its output it captured and then made available to the shipit task as the environment variable BUCKET_NAME.

This feature is experimental. There may be edge cases that aren’t handled well, so feedback is requested. Some details of the implementation or API may be altered in future versions.

Supported python versions

Poe the Poet officially supports python >3.6.2, and is tested with python 3.6 to 3.9 on macOS, linux and windows.

Contributing

There’s plenty to do, come say hi in the issues! 👋

Also check out the CONTRIBUTING.MD 🤓

Licence

MIT.