$schema: http://json-schema.org/draft-04/schema#
id: https://hg.mozilla.org/mozilla-central/raw-file/tip/taskcluster/docs/actions-schema.yml
title: Schema for Exposing Actions
description: |
  This document specifies the schema for the `public/actions.json` used by
  _decision tasks_ to expose actions that can be triggered by end-users.

  For the purpose of this document the _consumer_ is the user-interface that
  displays task results to the end-user and allows end-users to trigger actions
  defined by `public/actions.json`. A _consumer_ might be Treeherder.
  The _end-user_ is a developer who is inspecting the results, and wish to
  trigger actions.
type: object
properties:
  version:
    enum: [1]
    type: integer
  variables:
    type: object
    description: |
      Mapping from variable name to constants that can be referenced using
      `{$eval: '<variable>'}` within the task templates defined for each action.

      This is useful for commonly used constants that are used in many task
      templates. Whether it's to reduce the size of the `public/actions.json`
      artifact by reuseing large constants, or simply to make it easier to
      write task templates by exposing additional variables.

      These will overwrite any builtin variables, such as `taskGroupId`,
      `input`, `taskId`, `task`, and any further variables that future
      backwards compatible iterations of this specifcation adds. Hence, you
      should avoid declaring variables such as `input`, as it will shadow the
      builtin `input` variable.
    additionalProperties: true
  actions:
    type: array
    description: |
      List of actions that can be triggered.
    items:
      type: object
      properties:
        title:
          type: string
          maxLength: 255
          description: |
            Title text to be displayed on the button or link triggering the action.
        description:
          type: string
          maxLength: 4096
          description: |
            Human readable description of the action in markdown.
            Can be displayed in tooltip, popup and/or dialog when triggering
            the action.
        kind:
          enum:
            - task
          description: |
            Specifies the kind of action this is.

            The `task` _action kind_ is triggered by creating a task, following
            a task template.

            Other kinds might be added in the future. Consumers should ignore
            all entries featuring a `kind` property they don't recognize.
        context:
          type: array
          default: []
          items:
            type: object
            additionalProperties:
              type: string
              maxLength: 4096
            title: tag-set
            description: |
              A set of key-value pairs specifying a _tag-set_.
          description: |
            The `context` property determines in what context the action is
            relevant. Thus, what context the action should be presented to the
            end-user.

            The `context` property contains a set of tag-sets. A _tag-set_ is a
            set of key-value pairs. A task is said satisfy a tag-set if
            `task.tags` is a super-set of the given tag-set. An action is
            relevant for a task if the task satisfies at-least one of
            the tag-sets.

            Hence, an action with `context: [{a: '1'}, {b: '2'}]` is relevant
            for any task with `task.tags.a = '1'` or `task.tags.b = '2'`.
            An action with `context: [{a: '1', b: '2'}]` is only relevant for
            tasks with `task.tags.a = '1'` and `task.tags.b = '2'`.

            This allows restrictions of what tasks an action is relevant for.
            For example some tasks might not support running under a debugger.

            The keen reader observes that actions with `context: [{}]` are
            relevant for all tasks. Conversely, we have that tasks with
            `context: []` are irrelevant for all tasks. We abuse this property
            and define actions with `context: []` to be relevant for the
            _task-group_ only.

            That is an action with `context: []` should not be display in the
            context-sensitive menu for a task, rather it should be display when
            selecting the entire task-group. Presentation details are left for
            consumer to decide.

            Notice that the `context` property is optional, but defined to have
            a default value `context: []`. Hence, if the `context` is not
            specified consumer should take this to mean `context: []` implying
            that the action is relevant to the task-group, rather than any
            subset of tasks.
        schema:
          $ref: http://json-schema.org/schema
          description: |
            JSON schema for input parameters to the `task` template property.
            Consumers shall offer a user-interface where end-users can enter
            values that satisfy this schema. Furthermore, consumers **must**
            validate enter values against the given schema before parameterizing
            the `task` template property and triggering the action.

            In practice it's encourage that consumers employ a facility that
            can generate HTML forms from JSON schemas. However, if certain
            schemas are particularly complicated or common, consumers may also
            hand-write a user-interface for collecting the input. In this case
            the consumer **must** do a deep comparison between the schema given
            in the action, and the schema for which a custom user-interface have
            been written, and fall-back to an auto-generated form if the schema
            doesn't match.

            It is assumed that the JSON schema `description` property will be
            rendered as markdown when displayed as documentation for end-users.
            Producers of `public/actions.json` is encouraged to provide a
            detailed explanation of the input parameters using these
            `description` properties. And consumers are *strongly* encouraged
            to render `description` values as markdown.

            The `schema` property is optional, and if not given the input for
            `task` template parameterization shall be `null`.
        task:
          type: object
          title: task template
          description: |
            Task template for triggering the action.

            When an action have been selected in the appropriate context and
            input satisfying the `schema` (if any) has been collected. The
            action is triggered by parameterizing the task template given in
            this property, and creating the resulting task.

            The template is parameterized with the following variables:
              * `taskGroupId`
              * `taskId` (taskId, `null` if not triggered for a given task)
              * `task` (task definition, `null` if not triggered for a given task)
              * `input` (input matching `schema`, `null` if no schema is given)
              * Property defined in the `variables` property.

            The template is an object that is parameterized by:
              1. Replacing substrings `'${variable}'` in strings and object keys
                 with the value of the given `variable`.
              2. Replacing objects on the form `{$eval: 'variable'}` with the
                 value of of the given `variable`.
              3. Replacing objects on the form {$fromNow: 'timespan'} with a
                 timestamp of `timespan` from now. Where `timespan` is on the
                 form: `([0-9]+ *d(ays?)?)? *([0-9]+ *h(ours?)?)? *([0-9]+ *m(in(utes?)?)?)?`
              4. Replacing any object on the form `{$json: value}` with the
                 value of `JSON.stringify(result)` where `result` is the result
                 of recursive application of rules 1-4 on `value`.

            This template language is still incomplete and additional features
            will be added in the future. This statment will be changed when the
            features of the template language is locked, until then consumption
            of the `public/actions.json` artifact is experimental.
            # TODO: Freeze the template language with a specification of json-e

            This allows for dumping `input` and `taskId` into environment
            variables for the task to be created. The following task template
            injects `input` and `taskId` as environment variables:
            ```json
            {
              "workerType": "my-worker",
              "payload": {
                "created": {"$fromNow": ""},
                "deadline": {"$fromNow": "1 hour 15 minutes"},
                "expiration": {"$fromNow": "14 days"},
                "image": "my-docker-image",
                "env": {
                  "TASKID_TRIGGERED_FOR": "${taskId}",
                  "INPUT_JSON": {"$json": {"$eval": "input"}}
                },
                ...
              },
              ...
            }
            ```
      additionalProperties: false
      required:
        - title
        - description
        - kind
        - task
additionalProperties: false
required:
  - version
  - actions
  - variables
