1 files changed, 29 insertions, 0 deletions
diff --git a/lib/gitlab/exclusive_lease_helpers.rb b/lib/gitlab/exclusive_lease_helpers.rb
new file mode 100644
index 00000000000..ab6838adc6d
--- /dev/null
+++ b/lib/gitlab/exclusive_lease_helpers.rb
@@ -0,0 +1,29 @@
+module Gitlab
+  # This module provides helper methods which are intregrated with GitLab::ExclusiveLease
+  module ExclusiveLeaseHelpers
+    FailedToObtainLockError = Class.new(StandardError)
+
+    ##
+    # This helper method blocks a process/thread until the other process cancel the obrainted lease key.
+    #
+    # Note: It's basically discouraged to use this method in the unicorn's thread,
+    #       because it holds the connection until all `retries` is consumed.
+    #       This could potentially eat up all connection pools.
+    def in_lock(key, ttl: 1.minute, retries: 10, sleep_sec: 0.01.seconds)
+      lease = Gitlab::ExclusiveLease.new(key, timeout: ttl)
+
+      until uuid = lease.try_obtain
+        # Keep trying until we obtain the lease. To prevent hammering Redis too
+        # much we'll wait for a bit.
+        sleep(sleep_sec)
+        break if (retries -= 1) < 0
+      end
+
+      raise FailedToObtainLockError, 'Failed to obtain a lock' unless uuid
+
+      return yield
+    ensure
+      Gitlab::ExclusiveLease.cancel(key, uuid)
+    end
+  end
+end