Grape

Grape support is integrated in AppSignal Ruby gem versions 1.1 and up.

For older versions of the AppSignal Ruby gem, check grape-appsignal gem created by Mark Madsen.

Installation

A Grape application requires a few manual steps to get working.

1. Create a config/appsignal.yml configuration file or configure it with environment variables. For more information see the Ruby configuration page.

• Make sure AppSignal is required, require "appsignal".
• Require the Grape integration, require "appsignal/integrations/grape".
• Start AppSignal, Appsignal.start.

A Grape config.ru file looks something like this:

# config.ru
require File.expand_path("../config/environment", __FILE__)
require_relative "./api.rb"
 
Appsignal.config = Appsignal::Config.new(
  File.expand_path("../", __FILE__), # The root of your app
  ENV["RACK_ENV"] # The environment of your app (development/production)
)
 
Appsignal.start_logger
Appsignal.start
 
run Acme::App

An example of a Grape api.rb file:

# api.rb
# require these two files
require "appsignal"
require "appsignal/integrations/grape"
 
module Acme
  class API < Grape::API
    insert_before Grape::Middleware::Error, Appsignal::Grape::Middleware # Include this middleware
 
    prefix "api"
    format :json
    get "/" do
      { :message => "Hello world!" }
    end
  end
end

insert_before was introduced in Grape 0.19. If you use an earlier version use this approach:

use Appsignal::Grape::Middleware

After these steps, start your Grape application and wait for data to arrive in AppSignal.

Grape on Rails

Grape is often used in combination with Ruby on Rails as a mounted application. To make sure performance and error metrics from both Grape and Rails are captured we recommend the following configuration:

1. Install AppSignal for Rails as described in the documentation.
2. Add the Appsignal::Grape::Middleware to each grape-root file for every API, for example app/controllers/api/v1/root.rb.

# root.rb
require "appsignal/integrations/grape"
 
module Acme
  class API < Grape::API
    use Appsignal::Grape::Middleware # Include this middleware
 
    prefix "api"
    format :json
    get "/" do
      { :message => "Hello world!" }
    end
  end
end

Ignoring errors

To ignore a specific Grape error set the grape.skip_appsignal_error flag in the request environment. This will tell AppSignal to ignore the error that occurs during the request. This allows you to stop reporting of errors to AppSignal.

Only ignore errors like this if you need to ignore errors from a Grape app using code. See the ignore_errors option to ignore it for the entire app. If you don't want to be notified about an error, see our notification settings.

get "/" do
  env["grape.skip_appsignal_error"] = true # Add this line to an endpoint or callback
  raise "uh oh" # Example error, don't copy this
end

Note that if an error is rescued in the app itself using rescue_from AppSignal will not receive and track the error. The error will need to be manually set on the AppSignal transaction.

class Api < ::Grape::API
  insert_before Grape::Middleware::Error, Appsignal::Grape::Middleware
 
  format :json
 
  base.rescue_from :all do |error|
    Appsignal.set_error(error)
    error!({ :foo => "bar" }.to_json, 500)
  end
end

Example app

We have an example application in our examples repository on GitHub. The example shows how to set up AppSignal with Grape.