Move ChatOps docs from EE to core

ChatOps used to be in the Ultimate tier.

3 files changed, 61 insertions, 0 deletions

diff --git a/doc/ci/chatops/README.md b/doc/ci/chatops/README.md
new file mode 100644
index 00000000000..6ad1df7bb2a
--- /dev/null
+++ b/doc/ci/chatops/README.md
@@ -0,0 +1,61 @@
+# GitLab ChatOps
+
+> **Notes:**
+>
+> * [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4466) in [GitLab Ultimate](https://about.gitlab.com/pricing/) 10.6. [Moved](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24780) to [GitLab Core](https://about.gitlab.com/pricing/) in 11.9.
+>
+> * ChatOps is currently in alpha, with some important features missing like access control.
+
+GitLab ChatOps provides a method to interact with CI/CD jobs through chat services like Slack. Many organizations' discussion, collaboration, and troubleshooting is taking place in chat services these days, and having a method to run CI/CD jobs with output posted back to the channel can significantly augment a team's workflow.
+
+## How it works
+
+GitLab ChatOps is built upon two existing features, [GitLab CI/CD](../README.md) and [Slack Slash Commmands](../../user/project/integrations/slack_slash_commands.md).
+
+A new `run` action has been added to the [slash commands](../../integration/slash_commands.md), which takes two arguments: a `<job name>` to execute and the `<job arguments>`. When executed, ChatOps will look up the specified job name and attempt to match it to a corresponding job in [.gitlab-ci.yml](../yaml/README.md). If a matching job is found on `master`, a pipeline containing just that job is scheduled. Two additional [CI/CD variables](../variables/README.html#predefined-variables-environment-variables) are passed to the job: `CHAT_INPUT` contains any additional arguments, and `CHAT_CHANNEL` is set to the name of channel the action was triggered in.
+
+After the job has finished, its output is sent back to Slack provided it has completed within 30 minutes. If a job takes more than 30 minutes to run it must use the Slack API to manually send data back to a channel.
+
+[Developer access and above](../../user/permissions.html#project-members-permissions) is required to use the `run` command. If a job should not be able to be triggered from chat, it can be set to `except: [chat]`.
+
+## Creating a ChatOps CI job
+
+Since ChatOps is built upon GitLab CI/CD, the job has all the same features and functions available. There a few best practices to consider however when creating ChatOps jobs:
+
+* It is strongly recommended to set `only: [chat]` so the job does not run as part of the standard CI pipeline.
+* If the job is set to `when: manual`, the pipeline will be created however the job will wait to be started.
+* It is important to keep in mind that there is very limited support for access control. If the user who triggered the slash command is a developer in the project, the job will run. The job itself can utilize existing [CI/CD variables](../variables/README.html#predefined-environment-variables) like `GITLAB_USER_ID` to perform additional rights validation, however these variables can be [overridden](https://docs.gitlab.com/ce/ci/variables/README.html#priority-of-variables).
+
+### Controlling the ChatOps reply
+
+For jobs with a single command, its output is automatically sent back to the channel as a reply. For example the chat reply of the following job is simply `Hello World.`
+
+```yaml
+hello-world:
+  stage: chatops
+  only: [chat]
+  script:
+    - echo "Hello World."
+```
+
+Jobs that contain multiple commands, or have a `before_script`, include additional content in the chat reply. In these cases both the commands and their output are included, with the commands wrapped in ANSI colors codes.
+
+To selectively reply with the output of one command, its output must be bounded by the `chat_reply` section. For example, the following job will list the files in the current directory.
+
+```yaml
+ls:
+  stage: chatops
+  only: [chat]
+  script:
+    - echo "This command will not be shown."
+    - echo -e "section_start:$( date +%s ):chat_reply\r\033[0K\n$( ls -la )\nsection_end:$( date +%s ):chat_reply\r\033[0K"
+```
+
+## GitLab ChatOps icon
+
+Say Hi to our ChatOps bot.
+You can find and download the official GitLab ChatOps icon here.
+
+![GitLab ChatOps bot icon](img/gitlab-chatops-icon-small.png)
+
+[Download bigger image](img/gitlab-chatops-icon.png)
diff --git a/doc/ci/chatops/img/gitlab-chatops-icon-small.png b/doc/ci/chatops/img/gitlab-chatops-icon-small.png
new file mode 100644
index 00000000000..71cc5dba5cf
--- /dev/null
+++ b/doc/ci/chatops/img/gitlab-chatops-icon-small.png
diff --git a/doc/ci/chatops/img/gitlab-chatops-icon.png b/doc/ci/chatops/img/gitlab-chatops-icon.png
new file mode 100644
index 00000000000..3ba8bd308e3
--- /dev/null
+++ b/doc/ci/chatops/img/gitlab-chatops-icon.png