Add support for Workhorse notifications

1 files changed, 14 insertions, 0 deletions

diff --git a/lib/gitlab/workhorse.rb b/lib/gitlab/workhorse.rb
index 3ff9f9eb5e7..ca4eba48a8b 100644
--- a/lib/gitlab/workhorse.rb
+++ b/lib/gitlab/workhorse.rb
@@ -8,6 +8,7 @@ module Gitlab
     VERSION_FILE = 'GITLAB_WORKHORSE_VERSION'.freeze
     INTERNAL_API_CONTENT_TYPE = 'application/vnd.gitlab-workhorse+json'.freeze
     INTERNAL_API_REQUEST_HEADER = 'Gitlab-Workhorse-Api-Request'.freeze
+    NOTIFICATION_CHANNEL = 'workhorse:notifications'.freeze
 
     # Supposedly the effective key size for HMAC-SHA256 is 256 bits, i.e. 32
     # bytes https://tools.ietf.org/html/rfc4868#section-2.6
@@ -154,6 +155,19 @@ module Gitlab
         Rails.root.join('.gitlab_workhorse_secret')
       end
 
+      def ensure_and_notify(key, value, expire: nil, overwrite: true)
+        Gitlab::Redis.with do |redis|
+          result = redis.set(key, value, ex: expire, nx: !overwrite)
+          if result
+            payload = "#{key}=#{value}"
+            redis.publish(RUNNER_NOTIFICATION_CHANNEL, payload)
+            value
+          else
+            redis.get(key)
+          end
+        end
+      end
+
       protected
 
       def encode(hash)