Adds remote mirror table migration

1 files changed, 52 insertions, 0 deletions

diff --git a/app/services/concerns/exclusive_lease_guard.rb b/app/services/concerns/exclusive_lease_guard.rb
new file mode 100644
index 00000000000..30be6accc32
--- /dev/null
+++ b/app/services/concerns/exclusive_lease_guard.rb
@@ -0,0 +1,52 @@
+#
+# Concern that helps with getting an exclusive lease for running a block
+# of code.
+#
+# `#try_obtain_lease` takes a block which will be run if it was able to
+# obtain  the lease. Implement `#lease_timeout` to configure the timeout
+# for the exclusive lease. Optionally override `#lease_key` to set the
+# lease key, it defaults to the class name with underscores.
+#
+module ExclusiveLeaseGuard
+  extend ActiveSupport::Concern
+
+  def try_obtain_lease
+    lease = exclusive_lease.try_obtain
+
+    unless lease
+      log_error('Cannot obtain an exclusive lease. There must be another instance already in execution.')
+      return
+    end
+
+    begin
+      yield lease
+    ensure
+      release_lease(lease)
+    end
+  end
+
+  def exclusive_lease
+    @lease ||= Gitlab::ExclusiveLease.new(lease_key, timeout: lease_timeout)
+  end
+
+  def lease_key
+    @lease_key ||= self.class.name.underscore
+  end
+
+  def lease_timeout
+    raise NotImplementedError,
+          "#{self.class.name} does not implement #{__method__}"
+  end
+
+  def release_lease(uuid)
+    Gitlab::ExclusiveLease.cancel(lease_key, uuid)
+  end
+
+  def renew_lease!
+    exclusive_lease.renew
+  end
+
+  def log_error(message, extra_args = {})
+    logger.error(message)
+  end
+end