1 files changed, 44 insertions, 0 deletions
diff --git a/lib/gitlab/faraday/error_callback.rb b/lib/gitlab/faraday/error_callback.rb
new file mode 100644
index 00000000000..f99be5b4d04
--- /dev/null
+++ b/lib/gitlab/faraday/error_callback.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Faraday
+    # Simple Faraday Middleware that catches any error risen during the request and run the configured callback.
+    # (https://lostisland.github.io/faraday/middleware/)
+    #
+    # By default, a no op callback is setup.
+    #
+    # Note that the error is not swallowed: it will be rerisen again. In that regard, this callback acts more
+    # like an error spy than anything else.
+    #
+    # The callback has access to the request `env` and the exception instance. For more details, see
+    # https://lostisland.github.io/faraday/middleware/custom
+    #
+    # Faraday.new do |conn|
+    #   conn.request(
+    #     :error_callback,
+    #     callback: -> (env, exception) { Rails.logger.debug("Error #{exception.class.name} when trying to contact #{env[:url]}" ) }
+    #   )
+    #   conn.adapter(:net_http)
+    # end
+    class ErrorCallback < ::Faraday::Middleware
+      def initialize(app, options = nil)
+        super(app)
+        @options = ::Gitlab::Faraday::ErrorCallback::Options.from(options) # rubocop: disable CodeReuse/ActiveRecord
+      end
+
+      def call(env)
+        @app.call(env)
+      rescue => e
+        @options.callback&.call(env, e)
+
+        raise
+      end
+
+      class Options < ::Faraday::Options.new(:callback)
+        def callback
+          self[:callback]
+        end
+      end
+    end
+  end
+end