1 files changed, 86 insertions, 0 deletions
diff --git a/app/models/ci/pipeline_status.rb b/app/models/ci/pipeline_status.rb
new file mode 100644
index 00000000000..048047d0e34
--- /dev/null
+++ b/app/models/ci/pipeline_status.rb
@@ -0,0 +1,86 @@
+# This class is not backed by a table in the main database.
+# It loads the latest Pipeline for the HEAD of a repository, and caches that
+# in Redis.
+module Ci
+  class PipelineStatus
+    attr_accessor :sha, :status, :project, :loaded
+
+    delegate :commit, to: :project
+
+    def self.load_for_project(project)
+      new(project).tap do |status|
+        status.load_status
+      end
+    end
+
+    def initialize(project, sha: nil, status: nil)
+      @project = project
+      @sha = sha
+      @status = status
+    end
+
+    def has_status?
+      loaded? && sha.present? && status.present?
+    end
+
+    def load_status
+      return if loaded?
+
+      if has_cache?
+        load_from_cache
+      else
+        load_from_commit
+        store_in_cache
+      end
+
+      self.loaded = true
+    end
+
+    def load_from_commit
+      return unless commit
+
+      self.sha = commit.sha
+      self.status = commit.status
+    end
+
+    # We only cache the status for the HEAD commit of a project
+    # This status is rendered in project lists
+    def store_in_cache_if_needed
+      return unless sha
+      return delete_from_cache unless commit
+      store_in_cache if commit.sha == self.sha
+    end
+
+    def load_from_cache
+      Gitlab::Redis.with do |redis|
+        self.sha, self.status = redis.hmget(cache_key, :sha, :status)
+      end
+    end
+
+    def store_in_cache
+      Gitlab::Redis.with do |redis|
+        redis.mapped_hmset(cache_key, { sha: sha, status: status })
+      end
+    end
+
+    def delete_from_cache
+      Gitlab::Redis.with do |redis|
+        redis.del(cache_key)
+      end
+    end
+
+    def has_cache?
+      Gitlab::Redis.with do |redis|
+        redis.exists(cache_key)
+      end
+    end
+
+    def loaded?
+      self.loaded
+    end
+
+    def cache_key
+      "projects/#{project.id}/build_status"
+    end
+  end
+end