Merge branch 'expose-deployment-variables' into 'master' 25743-clean-up-css-for-project-alerts-and-flash-notifications

Pass variables from deployment project services to CI runner

## What does this MR do?

This commit introduces the concept of deployment variables - variables
that are collected from deployment services and passed to CI runner
during a deployment build.
Deployment services specify the variables by overriding
"predefined_variables" method.

This commit also configures variables for KubernetesService

## Why was this MR needed?

We need these values for https://gitlab.com/gitlab-org/gitlab-ce/issues/23580

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- ~~[ ] API support added~~
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Refers to https://gitlab.com/gitlab-org/gitlab-ce/issues/23580

See merge request !8107

4 files changed, 22 insertions, 1 deletions

diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index fdbf28a1d68..591aba6bdc9 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -155,7 +155,7 @@ module Ci
     end
 
     def has_environment?
-      self.environment.present?
+      environment.present?
     end
 
     def starts_environment?
@@ -221,6 +221,7 @@ module Ci
       variables += pipeline.predefined_variables
       variables += runner.predefined_variables if runner
       variables += project.container_registry_variables
+      variables += project.deployment_variables if has_environment?
       variables += yaml_variables
       variables += user_variables
       variables += project.secret_variables
diff --git a/app/models/project.rb b/app/models/project.rb
index 5d092ca42c2..5d5d6737dad 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -1230,6 +1230,12 @@ class Project < ActiveRecord::Base
     end
   end
 
+  def deployment_variables
+    return [] unless deployment_service
+
+    deployment_service.predefined_variables
+  end
+
   def append_or_update_attribute(name, value)
     old_values = public_send(name.to_s)
 
diff --git a/app/models/project_services/deployment_service.rb b/app/models/project_services/deployment_service.rb
index 55e98c31251..da6be9dd7b7 100644
--- a/app/models/project_services/deployment_service.rb
+++ b/app/models/project_services/deployment_service.rb
@@ -8,4 +8,8 @@ class DeploymentService < Service
   def supported_events
     []
   end
+
+  def predefined_variables
+    []
+  end
 end
diff --git a/app/models/project_services/kubernetes_service.rb b/app/models/project_services/kubernetes_service.rb
index 80ae1191108..f5fbf8b353b 100644
--- a/app/models/project_services/kubernetes_service.rb
+++ b/app/models/project_services/kubernetes_service.rb
@@ -83,6 +83,16 @@ class KubernetesService < DeploymentService
     { success: false, result: err }
   end
 
+  def predefined_variables
+    variables = [
+      { key: 'KUBE_URL', value: api_url, public: true },
+      { key: 'KUBE_TOKEN', value: token, public: false },
+      { key: 'KUBE_NAMESPACE', value: namespace, public: true }
+    ]
+    variables << { key: 'KUBE_CA_PEM', value: ca_pem, public: true } if ca_pem.present?
+    variables
+  end
+
   private
 
   def build_kubeclient(api_path = '/api', api_version = 'v1')