ci: Introduce dedicated cache for the 'setup-test-env' job

This job can take advantage of the Go cache (i.e. '.go/pkg/mod/'), but
other "Rails" jobs don't need this folder which currently contains 48554
files.

This should speed up the cache download for the "Rails" jobs.
Signed-off-by: Rémy Coutable <remy@rymai.me>

.gitlab/ci/global.gitlab-ci.yml

@@ -16,15 +16,23 @@
     - source scripts/utils.sh
     - source scripts/prepare_build.sh
 
-.rails-cache:
+.setup-test-env-cache:
   cache:
-    key: "rails-v3"
+    key: "setup-test-env-v1"
     paths:
       - vendor/ruby/
       - vendor/gitaly-ruby/
       - .go/pkg/mod/
     policy: pull
 
+.rails-cache:
+  cache:
+    key: "rails-v4"
+    paths:
+      - vendor/ruby/
+      - vendor/gitaly-ruby/
+    policy: pull
+
 .static-analysis-cache:
   cache:
     key: "static-analysis-v2"

.gitlab/ci/rails.gitlab-ci.yml

@@ -141,6 +141,7 @@
 setup-test-env:
   extends:
     - .rails-job-base
+    - .setup-test-env-cache
     - .rails:rules:default-refs-code-backstage-qa
     - .use-pg11
   stage: prepare
@@ -180,14 +181,20 @@ setup-test-env:
       - tmp/tests/second_storage/
     when: always
 
-update-rails-cache:
+update-setup-test-env-cache:
   extends:
     - setup-test-env
     - .shared:rules:update-cache
-  artifacts: {}  # This job's purpose is only to update the cache.
+  artifacts:
+    paths: []  # This job's purpose is only to update the cache.
   cache:
     policy: push  # We want to rebuild the cache from scratch to ensure stale dependencies are cleaned up.
 
+update-rails-cache:
+  extends:
+    - update-setup-test-env-cache
+    - .rails-cache
+
 .coverage-base:
   extends:
     - .default-retry

doc/development/pipelines.md

@@ -493,6 +493,7 @@ request, be sure to start the `dont-interrupt-me` job before pushing.
 1. We currently have several different caches defined in
    [`.gitlab/ci/global.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/global.gitlab-ci.yml),
    with fixed keys:
+   - `.setup-test-env-cache`.
    - `.rails-cache`.
    - `.static-analysis-cache`.
    - `.coverage-cache`
@@ -500,6 +501,7 @@ request, be sure to start the `dont-interrupt-me` job before pushing.
    - `.yarn-cache`.
    - `.assets-compile-cache` (the key includes `${NODE_ENV}` so it's actually two different caches).
 1. Only 6 specific jobs, running in 2-hourly scheduled pipelines, are pushing (i.e. updating) to the caches:
+   - `update-setup-test-env-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-rails-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-static-analysis-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
    - `update-coverage-cache`, defined in [`.gitlab/ci/rails.gitlab-ci.yml`](https://gitlab.com/gitlab-org/gitlab/blob/master/.gitlab/ci/rails.gitlab-ci.yml).
@@ -642,6 +644,7 @@ that are scoped to a single [configuration keyword](../ci/yaml/README.md#job-key
 |------------------|-------------|
 | `.default-retry` | Allows a job to [retry](../ci/yaml/README.md#retry) upon `unknown_failure`, `api_failure`, `runner_system_failure`, `job_execution_timeout`, or `stuck_or_timeout_failure`. |
 | `.default-before_script` | Allows a job to use a default `before_script` definition suitable for Ruby/Rails tasks that may need a database running (e.g. tests). |
+| `.setup-test-env-cache` | Allows a job to use a default `cache` definition suitable for setuping test environment for subsequent Ruby/Rails tasks. |
 | `.rails-cache` | Allows a job to use a default `cache` definition suitable for Ruby/Rails tasks. |
 | `.static-analysis-cache` | Allows a job to use a default `cache` definition suitable for static analysis tasks. |
 | `.coverage-cache` | Allows a job to use a default `cache` definition suitable for coverage tasks. |