# Copyright 2016 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
module Google
module Cloud
module ErrorReporting
##
# # Middleware
#
# Google::Cloud::ErrorReporting::Middleware defines a Rack Middleware
# that can automatically catch upstream exceptions and report them
# to Stackdriver Error Reporting.
#
class Middleware
EXCEPTION_KEYS = ["sinatra.error", "rack.exception"].freeze
# A Google::Cloud::ErrorReporting::Project client used to report
# error events.
attr_reader :error_reporting
##
# Construct a new instance of Middleware.
#
# @param [Rack::Application] app The Rack application
# @param [Google::Cloud::ErrorReporting::Project] error_reporting A
# Google::Cloud::ErrorReporting::Project client for reporting
# exceptions
# @param [Hash] kwargs Hash of configuration settings. Used for backward
# API compatibility. See the [Configuration
# Guide](https://googleapis.github.io/google-cloud-ruby/docs/stackdriver/latest/file.INSTRUMENTATION_CONFIGURATION)
# for the prefered way to set configuration parameters.
#
# @return [Google::Cloud::ErrorReporting::Middleware] A new instance of
# Middleware
#
def initialize app, error_reporting: nil, **kwargs
require "rack"
require "rack/request"
@app = app
load_config kwargs
@error_reporting =
error_reporting ||
ErrorReporting::AsyncErrorReporter.new(
ErrorReporting.new(project: configuration.project_id,
credentials: configuration.credentials)
)
# Set module default client to reuse the same client. Update module
# configuration parameters.
ErrorReporting.class_variable_set :@@default_client, @error_reporting
end
##
# Implements the mandatory Rack Middleware call method.
#
# Catch all Exceptions from upstream and report them to Stackdriver
# Error Reporting. Unless the exception's class is defined to be ignored
# by this Middleware.
#
# @param [Hash] env Rack environment hash
#
def call env
response = @app.call env
# sinatra doesn't always raise the Exception, but it saves it in
# env['sinatra.error']
#
# some frameworks (i.e. hanami) will save a rendering exception in
# env['rack.exception']
EXCEPTION_KEYS.each do |exception_key|
next unless env[exception_key].is_a? Exception
report_exception env, env[exception_key]
end
response
rescue Exception => exception
report_exception env, exception
# Always raise exception backup
raise exception
end
##
# Report an given exception to Stackdriver Error Reporting.
#
# While it reports most of the exceptions. Certain Rails exceptions that
# maps to a HTTP status code less than 500 will be treated as not the
# app fault and ignored.
#
# @param [Hash] env Rack environment hash
# @param [Exception] exception The Ruby exception to report.
#
def report_exception env, exception
# Do not any exceptions that's specified by the ignore_classes list.
return if configuration.ignore_classes.include? exception.class
error_event = error_event_from_exception env, exception
# If this exception maps to a HTTP status code less than 500, do
# not report it.
status_code = error_event.http_status.to_i
return if status_code > 0 && status_code < 500
error_reporting.report error_event
end
##
# Creates a {Google::Cloud::ErrorReporting::ErrorEvent} based on the
# exception. Fill in the HttpRequestContext section of the ErrorEvent
# based on the HTTP Request headers.
#
# When used in Rails environment. It replies on
# ActionDispatch::ExceptionWrapper class to derive a HTTP status code
# based on the exception's class.
#
# @param [Hash] env Rack environment hash
# @param [Exception] exception Exception to convert from
#
# @return [Google::Cloud::ErrorReporting::ErrorEvent] The gRPC
# ErrorEvent object that's based on given env and exception
#
def error_event_from_exception env, exception
error_event = ErrorReporting::ErrorEvent.from_exception exception
# Inject service_context info into error_event object
error_event.service_name = configuration.service_name
error_event.service_version = configuration.service_version
# Inject http_request_context info into error_event object
rack_request = Rack::Request.new env
error_event.http_method = rack_request.request_method
error_event.http_url = rack_request.url
error_event.http_user_agent = rack_request.user_agent
error_event.http_referrer = rack_request.referrer
error_event.http_status = http_status exception
error_event.http_remote_ip = rack_request.ip
error_event
end
private
##
# Consolidate configurations from various sources. Also set
# instrumentation config parameters to default values if not set
# already.
#
def load_config **kwargs
project_id = kwargs[:project] || kwargs[:project_id]
configuration.project_id = project_id unless project_id.nil?
creds = kwargs[:credentials] || kwargs[:keyfile]
configuration.credentials = creds unless creds.nil?
service_name = kwargs[:service_name]
configuration.service_name = service_name unless service_name.nil?
service_vers = kwargs[:service_version]
configuration.service_version = service_vers unless service_vers.nil?
ignores = kwargs[:ignore_classes]
configuration.ignore_classes = ignores unless ignores.nil?
init_default_config
end
##
# Fallback to default configuration values if not defined already
def init_default_config
configuration.project_id ||= begin
(Cloud.configure.project_id ||
ErrorReporting::Project.default_project_id)
end
configuration.credentials ||= Cloud.configure.credentials
configuration.service_name ||=
ErrorReporting::Project.default_service_name
configuration.service_version ||=
ErrorReporting::Project.default_service_version
configuration.ignore_classes = Array(configuration.ignore_classes)
end
##
# Helper method to derive HTTP status code base on exception class in
# Rails. Returns nil if not in Rails environment.
#
# @param [Exception] exception An Ruby exception
#
# @return [Integer] A number that represents HTTP status code or nil if
# status code can't be determined
#
def http_status exception
http_status = nil
if defined?(ActionDispatch::ExceptionWrapper) &&
ActionDispatch::ExceptionWrapper.respond_to?(
:status_code_for_exception
)
http_status =
ActionDispatch::ExceptionWrapper.status_code_for_exception(
exception.class.name
)
end
http_status
end
##
# @private Get Google::Cloud::ErrorReporting.configure
def configuration
Google::Cloud::ErrorReporting.configure
end
end
end
end
end