# @PLUGIN@ - /checkers/ REST API

This page describes the checker-related REST endpoints that are added by the
@PLUGIN@ plugin.

Please also take note of the general information on the
[REST API](../../../Documentation/rest-api.html).

## <a id="checker-endpoints"> Checker Endpoints

### <a id="get-checker"> Get Checker
_'GET /checkers/[\{checker-id\}](#checker-id)'_

Retrieves a checker.

Note that only users with the [Administrate
Checkers](access-control.md#capability_administrateCheckers) global capability
are permitted to retrieve checkers.

#### Request

```
  GET /checkers/e1f530851409c89dbba927efd0fbbaf270bfaeae HTTP/1.0
```

As response a [CheckerInfo](#checker-info) entity is returned that describes the
checker.

#### Response

```
  HTTP/1.1 200 OK
  Content-Disposition: attachment
  Content-Type: application/json; charset=UTF-8
  )]}'
  {
    "uuid": "test:my-checker",
    "name": "MyChecker",
    "repository": "examples/Foo",
    "blocking": [],
    "description": "A simple checker.",
    "created_on": "2019-01-31 09:59:32.126000000"
  }
```

### <a id="create-checker"> Create Checker
_'POST /checkers/'_

Creates a new checker.

In the request body the data for the checker must be provided as a
[CheckerInput](#checker-input) entity.

Note that only users with the [Administrate
Checkers](access-control.md#capability_administrateCheckers) global capability
are permitted to create checkers.

#### Request

```
  POST /checkers/ HTTP/1.0
  Content-Type: application/json; charset=UTF-8
  {
    "uuid": "test:my-checker",
    "name": "MyChecker",
    "description": "A simple checker.",
    "repository": "examples/Foo",
  }
```

As response the [CheckerInfo](#checker-info) entity is returned that describes
the created checker.

#### Response

```
  HTTP/1.1 201 Created
  Content-Disposition: attachment
  Content-Type: application/json; charset=UTF-8
  )]}'
  {
    "uuid": "test:my-checker",
    "name": "MyChecker",
    "description": "A simple checker.",
    "repository": "examples/Foo",
    "created_on": "2019-01-31 09:59:32.126000000",
    "updated_on": "2019-01-31 09:59:32.126000000"
  }
```

### <a id="update-checker"> Update Checker
_'POST /checkers/[\{checker-id\}](#checker-id)'_

Updates a checker.

The new property values must be set in the request body in a
[CheckerInput](#checker-input) entity.

This REST endpoint supports partial updates of the checker property set. Only
properties that are set in the [CheckerInput](#checker-input) entity are
updated. Properties that are not set in the input (or that have `null` as value)
are not touched.

Unsetting properties:

* `uuid`: Cannot be unset or otherwise modified.
* `name`: Can be unset by setting an empty string ("") for it.
* `description`: Can be unset by setting an empty string ("") for it.
* `url`: Can be unset by setting an empty string ("") for it.
* '`repository`: Cannot be unset. Attempting to set it to an empty string ("")
  or a string that is empty after trim is rejected as `400 Bad Request`.
* `status`: Cannot be unset.
* `blocking`: Can be unset by setting an empty list (\[\]) for it.
* `query`: Can be unset by setting an empty string ("") for it. Note that the
  default for newly-created checkers is not empty; see [below](#query).

Note that only users with the [Administrate
Checkers](access-control.md#capability_administrateCheckers) global capability
are permitted to update checkers.

#### Request

```
  POST /checkers/e1f530851409c89dbba927efd0fbbaf270bfaeae HTTP/1.0
  Content-Type: application/json; charset=UTF-8
  {
    "description": "A simple checker."
  }
```

As response the [CheckerInfo](#checker-info) entity is returned that describes
the updated checker.

#### Response

```
  HTTP/1.1 200 OK
  Content-Disposition: attachment
  Content-Type: application/json; charset=UTF-8
  )]}'
  {
    "uuid": "test:my-checker",
    "name": "MyChecker",
    "description": "A simple checker.",
    "repository": "examples/Foo",
    "status": "ENABLED",
    "created_on": "2019-01-31 09:59:32.126000000",
    "updated_on": "2019-02-01 07:23:44.158000000"
  }
```

## <a id="ids"> IDs

### <a id="checker-id"> \{checker-id\}

The UUID of a checker.

UUIDs are of the form `SCHEME ':' ID`. The scheme and ID portions may only
contain alphanumeric characters (`a-z`, `A-Z`, `0-9`) plus the punctuation
characters `.`, `_`, and `-`. Thus UUIDs are URL-safe without escaping.

The scheme is by convention a short string (max 100 chars) associated with the
external system that created the checker, for example `jenkins`. The scheme must
also be a valid ref name component according to
[`git-check-ref-format`](https://git-scm.com/docs/git-check-ref-format), for
example it may not start or end with a period.

The ID is an arbitrary identifier that may have meaning to the external system.

UUIDs must be unique and are immutable after creation.

Checker names cannot be used as identifiers in the REST API since checker names
may be ambiguous.

## <a id="json-entities"> JSON Entities

### <a id="checker-info"> CheckerInfo
The `CheckerInfo` entity describes a checker.

| Field Name      |          | Description |
| --------------- | -------- | ----------- |
| `uuid`          |          | The [UUID](#checker-id) of the checker.
| `name`          |          | The name of the checker, may not be unique.
| `description`   | optional | The description of the checker.
| `url`           | optional | The URL of the checker.
| `repository`    |          | The (exact) name of the repository for which the checker applies.
| `status`        |          | The status of the checker; one of `ENABLED` or `DISABLED`.
| `blocking`      |          | A list of [conditions](#blocking-conditions) that describe when the checker should block change submission.
| `query`         | optional | A [query](#query) that limits changes for which the checker is relevant.
| `created_on`    |          | The [timestamp](../../../Documentation/rest-api.html#timestamp) of when the checker was created.
| `updated_on`    |          | The [timestamp](../../../Documentation/rest-api.html#timestamp) of when the checker was last updated.

### <a id="checker-input"> CheckerInput
The `CheckerInput` entity contains information for creating a checker.

| Field Name      |          | Description |
| --------------- | -------- | ----------- |
| `name`          | optional | The name of the checker. Must be specified for checker creation.
| `description`   | optional | The description of the checker.
| `url`           | optional | The URL of the checker.
| `repository`    | optional | The (exact) name of the repository for which the checker applies.
| `status`        | optional | The status of the checker; one of `ENABLED` or `DISABLED`.
| `blocking`      | optional | A list of [conditions](#blocking-conditions) that describe when the checker should block change submission.
| `query`         | optional | A [query](#query) that limits changes for which the checker is relevant.

## <a id="blocking-conditions"> Blocking Conditions

Blocking conditions allow checkers to specify the conditions under which checks
will block change submission. The conditions configured for a checker are
represented as a list of enum values. When there are multiple blocking
conditions, any one of them is sufficient to block submission; in other words,
conditions are ORed together.

There is currently only a single type of blocking condition:
`STATE_NOT_PASSING`. Intuitively, if a checker sets this blocking condition,
that means that users need to wait for all checks, for example build and test,
to pass before submitting the change. In other words, we might say the checker
is _required_.

Technically, `STATE_NOT_PASSING` requires the combined check state on the change
to be either `SUCCESSFUL`, `WARNING`, or `NOT_RELEVANT`.

## <a id="query"> Query

If the `query` field is specified in the checker config, then the checker is
only considered relevant for changes matching that query. The query field is
interpreted as a [change query](../../../Documentation/user-search.html), with a
limited subset of supported operators. By default, the query for newly-created
checkers is `status:open`. An empty query matches all changes.

In order to determine the relevant checkers for a given change, Gerrit first
looks up all enabled checkers matching that change's repository, then executes
the query for each checker in sequence. Because of this algorithm, there are
restrictions on which operators can be supported in checker queries:

* Operators related to projects are not supported, since the algorithm already
  only considers checkers with a matching repository.
* Full-text operators (e.g. `message`) are not supported, since these cannot be
  efficiently evaluated sequentially.
* Operators with an explicit or implied `self` user are not supported, since the
  algorithm must return the same set of relevant checkers regardless of the end
  user looking at the change.

Currently, the set of allowed query operators is:

`added, after, age, assignee, author, before, branch, committer, deleted, delta,
destination, dir, directory, ext, extension, f, file, footer, hashtag, intopic,
label, onlyextensions, onlyexts, ownerin, path, r, ref, reviewer, reviewerin,
size, status, submittable, topic, unresolved, wip`

---

Part of [Gerrit Code Review](../../../Documentation/index.html)