Graphql-ruby: Rake tooling

[rmosolgo]

I'd like to provide a set of rake tasks for managing a GraphQL system. I don't know a lot about Rake yet but I can imagine something like Rubocop's API:

require "graphql/rake_task"

# Define a bunch of tasks that will load the schema as needed
GraphQL::RakeTask.new(schema_name: "MyAppSchema")

One challenge is loading the schema: we may need to depend on :environment in Rails, or require a certain file to find the schema. Perhaps the user could define the task:

GraphQL::RakeTask.new do 
  # On Rails:
  task load_schema: :environment do 
    MyAppSchema 
  end 
  # Off Rails: 
  task :load_schema do 
    require "app/my_app_schema" 
    MyAppSchema 
  end 
end 

Also, should we support multiple schemas out of the box?

Which tasks should we implement? I can only think of schema dumping:

• Dump Schema to IDL
• Dump Schema to JSON

[chollier]

At @quri we do have a couple of Rake task that we use in our workflow for indeed dumping both the schema.json (useful for client GraphQL Client / apps to grab the latest schema) and the IDL (useful for spotting what's changing in a PR). This was heavily inspired by the talk the folks at @shopify gave at the GraphQL Summit.

Here is what our lib/tasks/graphql.rake looks like (hermes being the name of our GraphQL layer):

require 'json'

namespace :graphql do
  namespace :dump do
    desc 'Dumps the IDL schema into ./app/hermes/schema.graphql'
    task idl: [:environment] do
      target = Rails.root.join("app/graph/schema.graphql")
      schema = GraphQL::Schema::Printer.print_schema(Hermes::Schema)
      File.open(target, "w+") do |f|
        f.write(schema)
      end
      puts "Schema dumped into app/graph/schema.graphql"
    end

    desc 'Dumps the result of the introspection query into ./app/hermes/schema.json'
    task json: [:environment] do
      target = Rails.root.join("app/graph/schema.json")
      result = Hermes::Schema.execute(GraphQL::Introspection::INTROSPECTION_QUERY)
      File.open(target, "w+") do |f|
        f.write(JSON.pretty_generate(result))
      end
      puts "Schema dumped into app/graph/schema.json"
    end
  end

  desc 'Dumps both the IDL and result of introspection query in app/graph'
  task dump: ["graphql:dump:idl", "graphql:dump:json"]
end

as is it's not really re-usable but I could think of an initializer where maybe we could customize where does the files get dropped?

Happy to contribute as we have been using graphql-ruby heavily for a bit more than a year now and it's become a key component in our way to build our apps

[chollier]

We also in spec/hermes/schema_spec.rb have that piece that let's us ensure developers don't forget to check-in the latest dump in the code:

describe Hermes::Schema do
  it 'dumped schema should be up to date' do
    actual_schema = GraphQL::Schema::Printer.print_schema(described_class)
    dumped_schema = File.read(Rails.root.join("app/graph/schema.graphql"))

    expect(actual_schema).to eq(dumped_schema), 'GraphQL Schema is out of date. Please run rake graphql:dump'
  end
end

[rmosolgo]

Thanks for sharing! I literally _just_ finished this post 😆 http://rmosolgo.github.io/blog/2017/03/16/tracking-schema-changes-with-graphql-ruby/ Nice to know it's been working well for you too, I hope we can have something built-in to make it even easier. (I'm hoping for breaking change detection, for example.)

[rmosolgo]

Taking a crack at it here: https://github.com/rmosolgo/graphql-ruby/pull/687

Thanks again for sharing your solution, I took a page or two out of your book :)