Merge branch 'yaml-variables' into 'master'

Support yaml variables

This MR introduces ability to define variables from YAML.

```yaml
variables:
  DB_NAME: postgres

test:
  script: echo $DB_NAME
```

The variables are passed using the same API as Secure Variables. The API introduces additional parameter: public. All variables defined in YAML are marked as public. The GitLab Runner when detects public variables will pass them to the services. This makes it easy to fine tune linked services to for example define database name.

```yaml
services:
- postgres

variables:
  POSTGRES_DB: gitlab
```

The above example will run [postgres](https://registry.hub.docker.com/u/library/postgres/) and pass POSTGRES_DB to postgres container making it to create `gitlab` database instead of default `postges`.

**Note:** All variables will passed to all service containers. It's not designed to distinguish which variable should go where.

/cc @sytses @vsizov @dzaporozhets 

See merge request !227

1 files changed, 19 insertions, 1 deletions

diff --git a/app/models/build.rb b/app/models/build.rb
index 11bd967..4f6bf32 100644
--- a/app/models/build.rb
+++ b/app/models/build.rb
@@ -164,7 +164,7 @@ class Build < ActiveRecord::Base
   end
 
   def variables
-    project.variables
+    yaml_variables + project_variables
   end
 
   def duration
@@ -245,4 +245,22 @@ class Build < ActiveRecord::Base
   def path_to_trace
     "#{dir_to_trace}/#{id}.log"
   end
+
+  private
+
+  def yaml_variables
+    if commit.config_processor
+      commit.config_processor.variables.map do |key, value|
+        { key: key, value: value, public: true }
+      end
+    else
+      []
+    end
+  end
+
+  def project_variables
+    project.variables.map do |variable|
+      { key: variable.key, value: variable.value, public: false }
+    end
+  end
 end