Send chat user id to ChatOps jobs

doc/ci/chatops/index.md

@@ -9,6 +9,7 @@ type: index, concepts, howto
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/4466) in GitLab Ultimate 10.6.
 > - [Moved](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/24780) to GitLab Free in 11.9.
+> - `CHAT_USER_ID` was [introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/341798) in GitLab 14.4.
 
 GitLab ChatOps provides a method to interact with CI/CD jobs through chat services
 like Slack. Many organizations' discussion, collaboration, and troubleshooting takes
@@ -30,6 +31,7 @@ to the job:
 
 - `CHAT_INPUT` contains any additional arguments.
 - `CHAT_CHANNEL` is set to the name of channel the action was triggered in.
+- `CHAT_USER_ID` is set to the chat service's user ID of the user who triggered the slash command.
 
 When executed, ChatOps looks up the specified job name and attempts to match it
 to a corresponding job in [`.gitlab-ci.yml`](../yaml/index.md). If a matching job

doc/ci/variables/predefined_variables.md

@@ -20,6 +20,7 @@ There are also [Kubernetes-specific deployment variables](../../user/project/clu
 |------------------------------------------|--------|--------|-------------|
 | `CHAT_CHANNEL`                           | 10.6   | all    | The Source chat channel that triggered the [ChatOps](../chatops/index.md) command. |
 | `CHAT_INPUT`                             | 10.6   | all    | The additional arguments passed with the [ChatOps](../chatops/index.md) command. |
+| `CHAT_USER_ID`                           | 14.4   | all    | The chat service's user ID of the user who triggered the [ChatOps](../chatops/index.md) command. |
 | `CI`                                     | all    | 0.4    | Available for all jobs executed in CI/CD. `true` when available. |
 | `CI_API_V4_URL`                          | 11.7   | all    | The GitLab API v4 root URL. |
 | `CI_BUILDS_DIR`                          | all    | 11.10  | The top-level directory where builds are executed. |

lib/gitlab/chat/command.rb

@@ -66,7 +66,8 @@ module Gitlab
       def build_environment_variables(pipeline)
         pipeline.variables.build(
           [{ key: 'CHAT_INPUT', value: arguments },
-           { key: 'CHAT_CHANNEL', value: channel }]
+           { key: 'CHAT_CHANNEL', value: channel },
+           { key: 'CHAT_USER_ID', value: chat_name.chat_id }]
         )
       end
 

spec/lib/gitlab/chat/command_spec.rb

@@ -72,6 +72,7 @@ RSpec.describe Gitlab::Chat::Command do
 
       expect(vars['CHAT_INPUT']).to eq('foo')
       expect(vars['CHAT_CHANNEL']).to eq('123')
+      expect(vars['CHAT_USER_ID']).to eq(chat_name.chat_id)
     end
   end
 end