failover to other random endpoint when one is unreachable. Initialize with randomly choosen endpoint to somewhat fairly distribute load

Author: darragh

Rakefile

@@ -4,13 +4,15 @@ require 'rake/clean'
 
 Rake::TestTask.new("spec:unit") do |spec|
   spec.libs.push "lib"
+  spec.libs.push "spec"
   spec.libs.push "spec/unit"
   spec.test_files = FileList['spec/unit/**/*_spec.rb']
   spec.warning = true
 end
 
 Rake::TestTask.new("spec:integration") do |spec|
   spec.libs.push "lib"
+  spec.libs.push "spec"
   spec.test_files = FileList['spec/integration/**/*_spec.rb']
   spec.warning = true
 end

lib/intercom.rb

@@ -23,6 +23,7 @@ module Intercom
   @hostname = "api.intercom.io"
   @protocol = "https"
   @endpoints = nil
+  @current_endpoint = nil
   @app_id = nil
   @api_key = nil
 
@@ -48,19 +49,32 @@ def self.api_key=(api_key)
   def self.target_base_url
     raise ArgumentError, "You must set both Intercom.app_id and Intercom.api_key to use this client. See https://github.com/intercom/intercom-ruby for usage examples." if [@app_id, @api_key].any?(&:nil?)
     basic_auth_part = "#{@app_id}:#{@api_key}@"
-    endpoints[0].gsub(/(https?:\/\/)(.*)/, "\\1#{basic_auth_part}\\2")
+    current_endpoint.gsub(/(https?:\/\/)(.*)/, "\\1#{basic_auth_part}\\2")
   end
 
   def self.send_request_to_path(request)
     request.execute(target_base_url)
   rescue Intercom::ServiceReachableError => e
-    if @endpoints && @endpoints.length > 1
+    if endpoints.length > 1
+      endpoint_unreachable
       request.execute(target_base_url)
     else
       raise e
     end
   end
 
+  def self.current_endpoint
+    @current_endpoint ||= random_endpoint
+  end
+
+  def self.random_endpoint
+    (endpoints.shuffle - [@current_endpoint]).first
+  end
+
+  def self.endpoint_unreachable
+    @current_endpoint = random_endpoint
+  end
+
   def self.post(path, payload_hash)
     send_request_to_path(Intercom::Request.post(path, payload_hash))
   end
@@ -101,10 +115,12 @@ def self.hostname=(override) #nodoc
 
   def self.endpoint=(endpoint) #nodoc
     self.endpoints = [endpoint]
+    @current_endpoint = nil
   end
 
   def self.endpoints=(endpoints) #nodoc
     @endpoints = endpoints
+    @current_endpoint = nil
   end
 
   def self.endpoints

spec/integration/intercom_api_integration_spec.rb

@@ -1,5 +1,4 @@
-require 'intercom'
-require 'minitest/autorun'
+require "spec_helper"
 
 describe "api.intercom.io dummy data requests" do
   before :each do
@@ -56,7 +55,7 @@
   end
 
   it "should failover to good endpoint when first one is un-reachable" do
-    Intercom.endpoints = ["http://127.0.0.7", "https://api.intercom.io"]
+    Intercom.endpoints = unshuffleable_array(["http://127.0.0.7", "https://api.intercom.io"])
     user = Intercom::User.find(:email => "[email protected]")
     user.name.must_equal "Somebody"
   end

spec/unit/spec_helper.rb spec/spec_helper.rb

@@ -97,4 +97,11 @@ def capture_exception(&block)
   rescue => e
     return e
   end
+end
+
+def unshuffleable_array(array)
+  def array.shuffle
+    self
+  end
+  array
 end

spec/unit/intercom_spec.rb

@@ -29,12 +29,12 @@
       before do
         @protocol = Intercom.protocol
         @hostname = Intercom.hostname
+        Intercom.endpoints = nil
       end
 
       after do
         Intercom.protocol = @protocol
         Intercom.hostname = @hostname
-        Intercom.endpoints = nil
       end
 
       it "allows overriding of the endpoint and protocol" do
@@ -46,7 +46,7 @@
       it "prefers endpoints" do
         Intercom.endpoint = "https://localhost:7654"
         Intercom.target_base_url.must_equal "https://abc123:super-secret-key@localhost:7654"
-        Intercom.endpoints = ["http://example.com","https://localhost:7654"]
+        Intercom.endpoints = unshuffleable_array(["http://example.com","https://localhost:7654"])
         Intercom.target_base_url.must_equal "http://abc123:[email protected]"
       end