retry requests when rate limit reached

droplet_kit.gemspec

@@ -20,6 +20,7 @@ Gem::Specification.new do |spec|
   spec.required_ruby_version = '>= 2.5.0'
 
   spec.add_dependency 'faraday', '>= 0.15'
+  spec.add_dependency 'faraday-retry', '~> 2.2.0'
   spec.add_dependency 'kartograph', '~> 0.2.8'
   spec.add_dependency 'resource_kit', '~> 0.1.5'
   spec.add_dependency 'virtus', '>= 1.0.3', '<= 3'

lib/droplet_kit/client.rb

@@ -1,30 +1,47 @@
 # frozen_string_literal: true
 
 require 'faraday'
+require 'faraday/retry'
 require 'droplet_kit/utils'
 
 module DropletKit
   class Client
     DEFAULT_OPEN_TIMEOUT = 60
     DEFAULT_TIMEOUT = 120
+    DEFAULT_RETRY_MAX = 3
+    DEFAULT_RETRY_WAIT_MIN = 0
+
     DIGITALOCEAN_API = 'https://api.digitalocean.com'
 
-    attr_reader :access_token, :api_url, :open_timeout, :timeout, :user_agent
+    attr_reader :access_token, :api_url, :open_timeout, :timeout, :user_agent, :retry_max, :retry_wait_min
 
     def initialize(options = {})
       options = DropletKit::Utils.transform_keys(options, &:to_sym)
-      @access_token = options[:access_token]
-      @api_url      = options[:api_url] || DIGITALOCEAN_API
-      @open_timeout = options[:open_timeout] || DEFAULT_OPEN_TIMEOUT
-      @timeout      = options[:timeout] || DEFAULT_TIMEOUT
-      @user_agent   = options[:user_agent]
+      @access_token   = options[:access_token]
+      @api_url        = options[:api_url] || DIGITALOCEAN_API
+      @open_timeout   = options[:open_timeout] || DEFAULT_OPEN_TIMEOUT
+      @timeout        = options[:timeout] || DEFAULT_TIMEOUT
+      @user_agent     = options[:user_agent]
+      @retry_max      = options[:retry_max] || DEFAULT_RETRY_MAX
+      @retry_wait_min = options[:retry_wait_min] || DEFAULT_RETRY_WAIT_MIN
     end
 
     def connection
       @faraday ||= Faraday.new connection_options do |req|
         req.adapter :net_http
         req.options.open_timeout = open_timeout
         req.options.timeout = timeout
+        req.request :retry, {
+          max: @retry_max,
+          interval: @retry_wait_min,
+          retry_statuses: [429],
+          # faraday-retry supports both the Retry-After and RateLimit-Reset
+          # headers, however, it favours the RateLimit-Reset one. To force it
+          # to use the Retry-After header, we override the header that it
+          # expects for the RateLimit-Reset header to something that we know
+          # we don't set.
+          rate_limit_reset_header: 'undefined'
+        }
       end
     end
 

lib/droplet_kit/error_handling_resourcable.rb

@@ -7,12 +7,6 @@ def self.included(base)
         case response.status
         when 200...299
           next
-        when 429
-          error = DropletKit::RateLimitReached.new("#{response.status}: #{response.body}")
-          error.limit = response.headers['RateLimit-Limit']
-          error.remaining = response.headers['RateLimit-Remaining']
-          error.reset_at = response.headers['RateLimit-Reset']
-          raise error
         else
           raise DropletKit::Error, "#{response.status}: #{response.body}"
         end

spec/lib/droplet_kit/client_spec.rb

@@ -51,6 +51,26 @@
 
       expect(client.timeout).to eq(timeout)
     end
+
+    it 'allows retry max to be set' do
+      retry_max = 10
+      client = described_class.new(
+        'access_token' => 'my-token',
+        'retry_max' => retry_max
+      )
+
+      expect(client.retry_max).to eq(retry_max)
+    end
+
+    it 'allows retry wait min to be set' do
+      retry_wait_min = 3
+      client = described_class.new(
+        'access_token' => 'my-token',
+        'retry_wait_min' => retry_wait_min
+      )
+
+      expect(client.retry_wait_min).to eq(retry_wait_min)
+    end
   end
 
   describe '#method_missing' do

spec/lib/droplet_kit/resources/account_resource_spec.rb

@@ -31,5 +31,11 @@
       let(:method) { :get }
       let(:action) { :info }
     end
+
+    it_behaves_like 'resource that handles rate limit retries' do
+      let(:path) { '/v2/account' }
+      let(:method) { :get }
+      let(:action) { :info }
+    end
   end
 end

spec/lib/droplet_kit/resources/droplet_resource_spec.rb

@@ -133,6 +133,13 @@ def check_droplet(droplet, tags = [], overrides = {})
       let(:action) { :find }
       let(:arguments) { { id: 123 } }
     end
+
+    it_behaves_like 'resource that handles rate limit retries' do
+      let(:path) { '/v2/droplets/123' }
+      let(:method) { :get }
+      let(:action) { :find }
+      let(:arguments) { { id: 123 } }
+    end
   end
 
   describe '#create' do

spec/spec_helper.rb

@@ -5,6 +5,7 @@
 SimpleCov.start
 
 require 'faraday'
+require 'faraday/retry'
 require 'addressable/uri'
 require 'droplet_kit'
 require 'webmock/rspec'

spec/support/shared_examples/common_errors.rb

@@ -3,22 +3,6 @@
 shared_examples_for 'resource that handles common errors' do
   let(:arguments) { {} }
 
-  it 'handles rate limit' do
-    response_body = { id: :rate_limit, message: 'Too much!!!' }
-    stub_do_api(path, method).to_return(body: response_body.to_json, status: 429, headers: {
-                                          'RateLimit-Limit' => 1200,
-                                          'RateLimit-Remaining' => 1193,
-                                          'RateLimit-Reset' => 1_402_425_459
-                                        })
-
-    expect { resource.send(action, arguments).to_a }.to raise_exception(DropletKit::Error) do |exception|
-      expect(exception.message).to match(/#{response_body[:message]}/)
-      expect(exception.limit).to eq 1200
-      expect(exception.remaining).to eq 1193
-      expect(exception.reset_at).to eq '1402425459'
-    end
-  end
-
   it 'handles unauthorized' do
     response_body = { id: :unauthorized, message: 'Nuh uh.' }
 

spec/support/shared_examples/rate_limit_retry.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+shared_examples_for 'resource that handles rate limit retries' do
+  let(:arguments) { {} }
+
+  it 'handles rate limit' do
+    response_body = { id: :rate_limit, message: 'example' }
+    stub_do_api(path, method).to_return(
+      [
+        {
+          body: nil,
+          status: 429,
+          headers: {
+            'RateLimit-Limit' => 1200,
+            'RateLimit-Remaining' => 1193,
+            'RateLimit-Reset' => 1_402_425_459,
+            'Retry-After' => 0 # Retry immediately in tests.
+          }
+        },
+        {
+          body: response_body.to_json,
+          status: 200,
+          headers: {
+            'RateLimit-Limit' => 1200,
+            'RateLimit-Remaining' => 1192,
+            'RateLimit-Reset' => 1_402_425_459
+          }
+        }
+      ]
+    )
+
+    expect { resource.send(action, arguments) }.not_to raise_error
+  end
+end