Merge branch 'master' into implement_lru_cache

Author: pushrax

.travis.yml

@@ -6,9 +6,9 @@ before_install:
   - scripts/install_toxiproxy.sh
 
 rvm:
-  - '2.3.1'
   - '2.4'
   - '2.5'
+  - '2.6'
 
 gemfile:
   - gemfiles/mysql2-0-4-10.gemfile

lib/semian/mysql2.rb

@@ -28,6 +28,10 @@ module Mysql2
       /MySQL client is not connected/i,
     )
 
+    TIMEOUT_ERROR = Regexp.union(
+      /Timeout waiting for a response/i,
+    )
+
     ResourceBusyError = ::Mysql2::ResourceBusyError
     CircuitOpenError = ::Mysql2::CircuitOpenError
     PingFailure = Class.new(::Mysql2::Error)
@@ -118,7 +122,7 @@ def connect(*args)
     def acquire_semian_resource(*)
       super
     rescue ::Mysql2::Error => error
-      if error.message =~ CONNECTION_ERROR || error.is_a?(PingFailure)
+      if error.message =~ CONNECTION_ERROR || error.message =~ TIMEOUT_ERROR || error.is_a?(PingFailure)
         semian_resource.mark_failed(error)
         error.semian_identifier = semian_identifier
       end

lib/semian/redis.rb

@@ -85,7 +85,7 @@ def connect
         begin
           raw_connect
         rescue SocketError, RuntimeError => e
-          raise ResolveError.new(semian_identifier) if (e.cause || e).to_s =~ /(can't resolve)|(name or service not known)/i
+          raise ResolveError.new(semian_identifier) if dns_resolve_failure?(e.cause || e)
           raise
         end
       end
@@ -111,6 +111,10 @@ def raise_if_out_of_memory(reply)
       return unless reply.message =~ /OOM command not allowed when used memory > 'maxmemory'\.\s*\z/
       raise ::Redis::OutOfMemoryError.new(reply.message)
     end
+
+    def dns_resolve_failure?(e)
+      e.to_s.match?(/(can't resolve)|(name or service not known)|(nodename nor servname provided, or not known)|(failure in name resolution)/i)
+    end
   end
 end
 

test/mysql2_test.rb

@@ -56,6 +56,31 @@ def test_query_errors_does_not_open_the_circuit
     end
   end
 
+  def test_read_timeout_error_open_the_circuit
+    client = connect_to_mysql!
+
+    (ERROR_THRESHOLD).times do
+      assert_raises Mysql2::Error do
+        # Should raise an exception like -
+        # Mysql2::Error Exception: [mysql_testing] Timeout waiting for a response from the last query. (waited 2 seconds)
+        client.query('SELECT sleep(5)')
+      end
+    end
+
+    assert_raises Mysql2::CircuitOpenError do
+      client.query('SELECT sleep(5)')
+    end
+
+    # After Mysql2::CircuitOpenError check regular queries are working fine.
+    query_string = "1 + 1"
+    result = nil
+    Timecop.travel(ERROR_TIMEOUT + 1) do
+      result = client.query("SELECT #{query_string};")
+    end
+
+    assert_equal 2, result.first[query_string]
+  end
+
   def test_connect_instrumentation
     notified = false
     subscriber = Semian.subscribe do |event, resource, scope, adapter|

test/redis_test.rb

@@ -186,6 +186,22 @@ def test_dns_resolution_failures_open_circuit
     end
   end
 
+  [
+    "Temporary failure in name resolution",
+    "Can't resolve example.com",
+    "name or service not known",
+    "Could not resolve hostname example.com: nodename nor servname provided, or not known",
+  ].each do |message|
+    test_suffix = message.gsub(/\W/, '_').downcase
+    define_method(:"test_dns_resolution_failure_#{test_suffix}") do
+      Redis::Client.any_instance.expects(:raw_connect).raises(message)
+
+      assert_raises Redis::ResolveError do
+        connect_to_redis!(host: 'example.com')
+      end
+    end
+  end
+
   def test_circuit_breaker_on_connect
     @proxy.downstream(:latency, latency: 500).apply do
       background { connect_to_redis! }

test/test_helper.rb

@@ -8,6 +8,8 @@
 require 'tempfile'
 require 'fileutils'
 require 'byebug'
+require 'mocha'
+require 'mocha/minitest'
 
 require 'helpers/background_helper'
 require 'helpers/circuit_breaker_helper'