Implement $CI_ENVIRONMENT_URL for jobs

We introduce ci_builds.environment_url and expand it when passing to
runners. In the future the deployment could also retrieve the URL from
the job instead of from the environment, which might have a different
external URL because of another deployment happened.

app/models/ci/build.rb

@@ -26,6 +26,10 @@ module Ci
 
     validates :coverage, numericality: true, allow_blank: true
     validates :ref, presence: true
+    validates :environment_url,
+              length: { maximum: 255 },
+              allow_nil: true,
+              addressable_url: true
 
     scope :unstarted, ->() { where(runner_id: nil) }
     scope :ignore_failures, ->() { where(allow_failure: false) }
@@ -132,6 +136,11 @@ module Ci
       ExpandVariables.expand(environment, simple_variables) if environment
     end
 
+    def expanded_environment_url
+      ExpandVariables.expand(environment_url, simple_variables) if
+        environment_url
+    end
+
     def has_environment?
       environment.present?
     end
@@ -178,22 +187,23 @@ module Ci
     # Variables whose value does not depend on other variables
     def simple_variables
       variables = predefined_variables
-      variables += project.predefined_variables
-      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
-      variables += trigger_request.user_variables if trigger_request
+      variables.concat(project.predefined_variables)
+      variables.concat(pipeline.predefined_variables)
+      variables.concat(runner.predefined_variables) if runner
+      variables.concat(project.container_registry_variables)
+      variables.concat(project.deployment_variables) if has_environment?
+      variables.concat(yaml_variables)
+      variables.concat(user_variables)
+      variables.concat(project.secret_variables)
+      variables.concat(trigger_request.user_variables) if trigger_request
       variables
     end
 
     # All variables, including those dependent on other variables
     def variables
       variables = simple_variables
-      variables += persisted_environment.predefined_variables if persisted_environment.present?
+      variables.concat(persisted_environment_variables) if
+        persisted_environment
       variables
     end
 
@@ -488,6 +498,13 @@ module Ci
       variables.concat(legacy_variables)
     end
 
+    def persisted_environment_variables
+      persisted_environment.predefined_variables <<
+        { key: 'CI_ENVIRONMENT_URL',
+          value: expanded_environment_url,
+          public: true }
+    end
+
     def legacy_variables
       variables = [
         { key: 'CI_BUILD_ID', value: id.to_s, public: true },

db/migrate/20170524195203_add_environment_url_to_ci_builds.rb

+class AddEnvironmentUrlToCiBuilds < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    add_column(:ci_builds, :environment_url, :string)
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170521184006) do
+ActiveRecord::Schema.define(version: 20170524195203) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -233,6 +233,7 @@ ActiveRecord::Schema.define(version: 20170521184006) do
     t.string "coverage_regex"
     t.integer "auto_canceled_by_id"
     t.boolean "retried"
+    t.string "environment_url"
   end
 
   add_index "ci_builds", ["auto_canceled_by_id"], name: "index_ci_builds_on_auto_canceled_by_id", using: :btree

lib/ci/gitlab_ci_yaml_processor.rb

@@ -61,6 +61,7 @@ module Ci
         allow_failure: job[:ignore],
         when: job[:when] || 'on_success',
         environment: job[:environment_name],
+        environment_url: job[:environment_url],
         coverage_regex: job[:coverage],
         yaml_variables: yaml_variables(name),
         options: {

lib/gitlab/ci/config/entry/job.rb

@@ -141,6 +141,7 @@ module Gitlab
               variables: variables_defined? ? variables_value : nil,
               environment: environment_defined? ? environment_value : nil,
               environment_name: environment_defined? ? environment_value[:name] : nil,
+              environment_url: environment_defined? ? environment_value[:url] : nil,
               coverage: coverage_defined? ? coverage_value : nil,
               artifacts: artifacts_value,
               after_script: after_script_value,