Merge branch 'ci/cache-key' into 'master'

Added cache:key to .gitlab-ci.yml allowing to fine tune the caching

The `cache:key` allows you to define the affinity mask of caching, allowing to have single cache for all jobs, or cache per-job, or per-branch, or any other way you would need:

1. Cache per-build for all branches:

```
cache:
    key: "$CI_BUILD_NAME"
    untracked: true
```

2. Cache per-branch for all jobs:

```
cache:
    key: "$CI_BUILD_REF"
    untracked: true
```



/cc @DouweM @grzesiek @axil


See merge request !2436

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/ci/gitlab_ci_yaml_processor.rb b/lib/ci/gitlab_ci_yaml_processor.rb
index bcdfd38d292..1a3f662811a 100644
--- a/lib/ci/gitlab_ci_yaml_processor.rb
+++ b/lib/ci/gitlab_ci_yaml_processor.rb
@@ -115,6 +115,10 @@ module Ci
       end
 
       if @cache
+        if @cache[:key] && !validate_string(@cache[:key])
+          raise ValidationError, "cache:key parameter should be a string"
+        end
+
         if @cache[:untracked] && !validate_boolean(@cache[:untracked])
           raise ValidationError, "cache:untracked parameter should be an boolean"
         end
@@ -198,6 +202,10 @@ module Ci
     end
 
     def validate_job_cache!(name, job)
+      if job[:cache][:key] && !validate_string(job[:cache][:key])
+        raise ValidationError, "#{name} job: cache:key parameter should be a string"
+      end
+
       if job[:cache][:untracked] && !validate_boolean(job[:cache][:untracked])
         raise ValidationError, "#{name} job: cache:untracked parameter should be an boolean"
       end