Add option to trigger stats when exceptions occur

CHANGELOG.md

@@ -1,3 +1,6 @@
+# DEVELOP
+  * FEATURE: Stats for exceptions
+
 # 0.0.2
   * BUGFIX: Log location relative to `Adhearsion.root`
 

lib/adhearsion-stats/plugin.rb

@@ -9,9 +9,10 @@ class << self
   class Plugin < Adhearsion::Plugin
 
     config :statsd do
-      host "127.0.0.1",  desc: "The host that statsd is found at"
-      port 8125,         desc: "The port that statsd is found at"
-      log_metrics false, desc: "Whether or not to log stats sent to statsd"
+      host "127.0.0.1",     desc: "The host that statsd is found at"
+      port 8125,            desc: "The port that statsd is found at"
+      log_metrics false,    desc: "Whether or not to log stats sent to statsd"
+      exception_prefix nil, desc: "A string to prefix exceptions with - leave nil to disable"
     end
 
     init :statsd do
@@ -20,6 +21,14 @@ class Plugin < Adhearsion::Plugin
       AdhearsionStats.statsd = Statsd.new Adhearsion.config.statsd.host, Adhearsion.config.statsd.port
       AdhearsionStats.loaded = true
 
+      if Adhearsion.config.statsd.exception_prefix
+        Adhearsion::Events.register_callback(:exception) do |e, logger|
+          AdhearsionStats.increment "#{Adhearsion.config.statsd.exception_prefix}.#{e.class}"
+        end
+
+        logger.info "Adhearsion-Stats is watching for exceptions"
+      end
+
       logger.info "Adhearsion-Stats has been loaded"
     end
   end

spec/adhearsion-stats/plugin_spec.rb

@@ -11,13 +11,15 @@
   end
 
   describe "initialization" do
-    let(:logfile)       { double "File", 'sync=' => true }
-    let!(:dummy_logger) { AdhearsionStats::MetricsLogger.new(STDOUT) }
+    let(:exception_prefix) { nil }
+    let(:logfile)          { double "File", 'sync=' => true }
+    let!(:dummy_logger)    { AdhearsionStats::MetricsLogger.new(STDOUT) }
 
     before do
       File.stub(:open).and_return logfile
       AdhearsionStats::MetricsLogger.stub(:new).with(logfile).and_return dummy_logger
-      Adhearsion.config[:statsd].log_metrics = true
+      Adhearsion.config[:statsd].log_metrics      = true
+      Adhearsion.config[:statsd].exception_prefix = exception_prefix
       Adhearsion::Plugin.initializers.each { |plugin_initializer| plugin_initializer.run }
     end
 
@@ -55,6 +57,24 @@
           subject.timing "bar", 100
         end
       end
+
+      describe "Exceptions" do
+        context "when exception_prefix is nil" do
+          it "don't trigger a stat" do
+            subject.should_not_receive :increment
+            Adhearsion::Events.trigger_immediately :exception, StandardError.new
+          end
+        end
+
+        context "when exception_prefix is set" do
+          let(:exception_prefix) { "oh_noes" }
+
+          it "trigger a stat" do
+            subject.should_receive(:increment).with "oh_noes.StandardError"
+            Adhearsion::Events.trigger_immediately :exception, StandardError.new
+          end
+        end
+      end
     end
   end
 end