Accept maintainer_note in REST runner registration

Changelog: added

doc/api/runners.md

@@ -573,17 +573,18 @@ Register a new runner for the instance.
 POST /runners
 ```
 
-| Attribute    | Type    | Required | Description         |
-|--------------|---------|----------|---------------------|
-| `token`      | string  | yes      | [Registration token](#registration-and-authentication-tokens).  |
-| `description`| string  | no       | Runner's description|
-| `info`       | hash    | no       | Runner's metadata. You can include `name`, `version`, `revision`, `platform`, and `architecture`, but only `version` is displayed in the Admin area of the UI. |
-| `active`     | boolean | no       | Whether the runner is active   |
-| `locked`     | boolean | no       | Whether the runner should be locked for current project |
-| `run_untagged` | boolean | no     | Whether the runner should handle untagged jobs |
-| `tag_list`   | string array | no  | List of runner's tags |
-| `access_level`    | string | no   | The access_level of the runner; `not_protected` or `ref_protected` |
-| `maximum_timeout` | integer | no  | Maximum timeout set when this runner handles the job |
+| Attribute         | Type           | Required | Description                                                                                                                                                    |
+|-------------------|----------------|----------|----------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `token`           | string         | yes      | [Registration token](#registration-and-authentication-tokens).                                                                                                 |
+| `description`     | string         | no       | Runner's description                                                                                                                                           |
+| `info`            | hash           | no       | Runner's metadata. You can include `name`, `version`, `revision`, `platform`, and `architecture`, but only `version` is displayed in the Admin area of the UI. |
+| `active`          | boolean        | no       | Whether the runner is active                                                                                                                                   |
+| `locked`          | boolean        | no       | Whether the runner should be locked for current project                                                                                                        |
+| `run_untagged`    | boolean        | no       | Whether the runner should handle untagged jobs                                                                                                                 |
+| `tag_list`        | string array   | no       | List of runner's tags                                                                                                                                          |
+| `access_level`    | string         | no       | The access_level of the runner; `not_protected` or `ref_protected`                                                                                             |
+| `maximum_timeout` | integer        | no       | Maximum timeout set when this runner handles the job                                                                                                           |
+| `maintainer_note` | string         | no       | Free-form maintainer notes for the runner (255 characters)                                                                                                     |
 
 ```shell
 curl --request POST "https://gitlab.example.com/api/v4/runners" \

lib/api/ci/runner.rb

@@ -15,6 +15,7 @@ module API
         params do
           requires :token, type: String, desc: 'Registration token'
           optional :description, type: String, desc: %q(Runner's description)
+          optional :maintainer_note, type: String, desc: %q(Runner's maintainer notes)
           optional :info, type: Hash, desc: %q(Runner's metadata)
           optional :active, type: Boolean, desc: 'Should Runner be active'
           optional :locked, type: Boolean, desc: 'Should Runner be locked for current project'
@@ -25,7 +26,7 @@ module API
           optional :maximum_timeout, type: Integer, desc: 'Maximum timeout set when this Runner will handle the job'
         end
         post '/', feature_category: :runner do
-          attributes = attributes_for_keys([:description, :active, :locked, :run_untagged, :tag_list, :access_level, :maximum_timeout])
+          attributes = attributes_for_keys(%i[description maintainer_note active locked run_untagged tag_list access_level maximum_timeout])
             .merge(get_runner_details_from_request)
 
           @runner = ::Ci::RegisterRunnerService.new.execute(params[:token], attributes)

spec/requests/api/ci/runner/runners_post_spec.rb

@@ -30,6 +30,7 @@ RSpec.describe API::Ci::Runner, :clean_gitlab_redis_shared_state do
           post api('/runners'), params: {
             token: 'valid token',
             description: 'server.hostname',
+            maintainer_note: 'Some maintainer notes',
             run_untagged: false,
             tag_list: 'tag1, tag2',
             locked: true,
@@ -45,6 +46,7 @@ RSpec.describe API::Ci::Runner, :clean_gitlab_redis_shared_state do
           allow_next_instance_of(::Ci::RegisterRunnerService) do |service|
             expected_params = {
               description: 'server.hostname',
+              maintainer_note: 'Some maintainer notes',
               run_untagged: false,
               tag_list: %w(tag1 tag2),
               locked: true,