module Gitlab module Sherlock # Rack middleware used for tracking request metrics. class Middleware CONTENT_TYPES = /text\/html|application\/json/i IGNORE_PATHS = %r{^/sherlock} def initialize(app) @app = app end # env - A Hash containing Rack environment details. def call(env) if instrument?(env) call_with_instrumentation(env) else @app.call(env) end end def call_with_instrumentation(env) trans = transaction_from_env(env) retval = trans.run { @app.call(env) } Sherlock.collection.add(trans) retval end def instrument?(env) !!(env['HTTP_ACCEPT'] =~ CONTENT_TYPES && env['REQUEST_URI'] !~ IGNORE_PATHS) end def transaction_from_env(env) Transaction.new(env['REQUEST_METHOD'], env['REQUEST_URI']) end end end end