Use `workflow:rules:` for `.gitlab-ci.yml`

This adds a top-level `workflow:rules` to define
a prescripted workflow for CI.

We disable all other usage patterns for pipelines
that are not MR, master, stable, and tags.
Signed-off-by: Rémy Coutable <remy@rymai.me>

.gitlab-ci.yml

@@ -12,6 +12,24 @@ stages:
   - post-qa
   - pages
 
+workflow:
+  rules:
+    # If `$FORCE_GITLAB_CI` is set, create a pipeline.
+    - if: '$FORCE_GITLAB_CI'
+    # For merge requests, create a pipeline.
+    - if: '$CI_MERGE_REQUEST_IID'
+    # For `master` branch, create a pipeline (this includes on schedules, pushes, merges, etc.).
+    - if: '$CI_COMMIT_BRANCH == "master"'
+    # For tags, create a pipeline.
+    - if: '$CI_COMMIT_TAG'
+    # If `$GITLAB_INTERNAL` isn't set, don't create a pipeline.
+    - if: '$GITLAB_INTERNAL == null'
+      when: never
+    # For stable, auto-deploy, and security branches, create a pipeline.
+    - if: '$CI_COMMIT_BRANCH =~ /^[\d-]+-stable(-ee)?$/'
+    - if: '$CI_COMMIT_BRANCH =~ /^\d+-\d+-auto-deploy-\d+$/'
+    - if: '$CI_COMMIT_BRANCH =~ /^security\//'
+
 variables:
   RAILS_ENV: "test"
   NODE_ENV: "test"

doc/development/pipelines.md

@@ -42,7 +42,7 @@ The default image is currently
 `registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.6.5-golang-1.12-git-2.24-lfs-2.9-chrome-73.0-node-12.x-yarn-1.21-postgresql-9.6-graphicsmagick-1.3.34`.
 
 It includes Ruby 2.6.5, Go 1.12, Git 2.24, Git LFS 2.9, Chrome 73, Node 12, Yarn 1.21,
-PostgreSQL 9.6, and Graphics Magick 1.3.33.
+PostgreSQL 9.6, and Graphics Magick 1.3.34.
 
 The images used in our pipelines are configured in the
 [`gitlab-org/gitlab-build-images`](https://gitlab.com/gitlab-org/gitlab-build-images)
@@ -61,8 +61,8 @@ each pipeline includes default variables defined in
 ## Common job definitions
 
 Most of the jobs [extend from a few CI definitions](../ci/yaml/README.md#extends)
-that are scoped to a single
-[configuration parameter](../ci/yaml/README.md#configuration-parameters).
+defined in [`.gitlab/ci/global.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/global.gitlab-ci.yml)
+that are scoped to a single [configuration parameter](../ci/yaml/README.md#configuration-parameters).
 
 | Job definitions  | Description |
 |------------------|-------------|
@@ -72,10 +72,27 @@ that are scoped to a single
 | `.default-cache` | Allows a job to use a default `cache` definition suitable for Ruby/Rails and frontend tasks. |
 | `.use-pg9` | Allows a job to use the `postgres:9.6.17` and `redis:alpine` services. |
 | `.use-pg10` | Allows a job to use the `postgres:10.12` and `redis:alpine` services. |
+| `.use-pg11` | Allows a job to use the `postgres:11.6` and `redis:alpine` services. |
 | `.use-pg9-ee` | Same as `.use-pg9` but also use the `docker.elastic.co/elasticsearch/elasticsearch:6.4.2` services. |
 | `.use-pg10-ee` | Same as `.use-pg10` but also use the `docker.elastic.co/elasticsearch/elasticsearch:6.4.2` services. |
+| `.use-pg11-ee` | Same as `.use-pg11` but also use the `docker.elastic.co/elasticsearch/elasticsearch:6.4.2` services. |
 | `.as-if-foss` | Simulate the FOSS project by setting the `FOSS_ONLY='1'` environment variable. |
 
+## `workflow:rules`
+
+We're using the [`workflow:rules` keyword](../ci/yaml/README.md#workflowrules) to
+define default rules to determine whether or not a pipeline is created.
+
+These rules are defined in <https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab-ci.yml>
+and are as follows:
+
+1. If `$FORCE_GITLAB_CI` is set, create a pipeline.
+1. For merge requests, create a pipeline.
+1. For `master` branch, create a pipeline (this includes on schedules, pushes, merges, etc.).
+1. For tags, create a pipeline.
+1. If `$GITLAB_INTERNAL` isn't set, don't create a pipeline.
+   1. For stable, auto-deploy, and security branches, create a pipeline.
+
 ## `rules`, `if:` conditions and `changes:` patterns
 
 We're using the [`rules` keyword](../ci/yaml/README.md#rules) extensively.