API¶

Tasks¶

Tasks are created by extending the task class. Tasks must define a name and execute method.

from ixian.task import Task

class MyTask(Task):
    """
    The docstring will be used as help text.
    """

    name = 'my_task'
    short_description = 'description will be shown in general help'

    def execute(self, *args, **kwargs)
        print(args, kwargs)

Tasks are configured by setting class properties:

name: name used to reference task
description: short description of task
depends: list of dependencies
parents: list of parent tasks
check: list of checkers that determine if the task is complete
clean: function to run when –clean is specified

Checkers¶

Checkers determine if a task is complete or not. When a checker determines a task is complete it will be skipped unless --force or --clean is set. There are built-in checkers and support for custom checkers.

from ixian import Task
from ixian.modules.filesystem.file_hash import FileHash


class MyTask(Task):
    """
    This task will only run if input_file and output_file are modified or removed.
    """
    name = 'my_task'
    check = [
        FileHash('/input_file'),
        FileHash('/output_file')
    ]

See the [Checker documentation](check.md) for more detail.

Dependencies¶

Tasks may specify depend tasks that must run first. The dependency tree is examined and executed automatically. If a dependency’s checkers indicate the task must be run then that part of the dependency tree will be re-run.

class Parent(Task):
    name = 'parent'
    depends = ['child']

    def execute(self, *args, **kwargs):
        print("parent")


class Child1(Task):
    """
    whenever parent is called, this dependency runs first.
    """
    name = 'child_1'

    def execute(self, *args, **kwargs):
        print('child 1')

Tasks may also define parents in reverse.

class Child2(Task):
    """
    This task also is a dependency of parent.
    """
    name = 'child_2'
    parent = ['parent']

    def execute(self, *args, **kwargs):
        print('child 2')

The dependency tree for a task may be viewed by the built-in help

ix help parent

The status section lists the tree of tasks and their statuses.

STATUS
○ parent
    ○ child_1
    ○ child_2

State¶

Tasks define their state using checkers. State is used to identify the inputs and provide an identifier for the expected output for the run.

State is accessible to tasks through CONFIG.

class MyConfig(Config):

    @classproperty
    def TASK_HASH:
        """Hash can be used as the identifier for build artifacts."""
        return "{TASKS.MY_TASK.HASH}"

    @classproperty
    def TASK_STATE:
        """State useful for debugging task trees."""
        return "{TASKS.MY_TASK.STATE}"

Task dependencies are automatically added to task state. If a dependency

> CONFIG.MY_TASK.STATE

{

}