Merge pull request #121 from hennevogel/feature/status_500

Record exception class name

Author: hennevogel

CHANGELOG.md

@@ -14,6 +14,7 @@ For the full commit log, [see here](https://github.com/influxdata/influxdb-rails
 - Implement `perform_start.active_job` subscriber (https://guides.rubyonrails.org/active_support_instrumentation.html#perform-start-active-job)
 - Implement `perform.active_job` subscriber (https://guides.rubyonrails.org/active_support_instrumentation.html#perform-active-job)
 - Implement block instrumentation `InfluxDB::Rails.instrument do; 1 + 1; end`
+- Record unhandled exceptions as tags for process_action.action_controller
 
 ## v1.0.0, released 2019-10-23
 The Final release, no code changes.

README.md

@@ -71,10 +71,15 @@ Reported tags:
   method:      "PostsController#index",
   http_method: "GET",
   format:      "html",
-  status:      "200"
+  status:      ["200", ""]
+  exception:   ["", "ArgumentError"]
 }
 ```
 
+*Note*: If an exception happens during that particular instrumentation the
+`status` will be blank and the tag `exception` will contain the name of the
+exception class.
+
 ### Action View
 
 Reported ActiveSupport instrumentation hooks:

lib/influxdb/rails/middleware/request_subscriber.rb

@@ -19,6 +19,7 @@ def tags
             status:      payload[:status],
             format:      payload[:format],
             http_method: payload[:method],
+            exception:   payload[:exception]&.first,
           }
         end
 

spec/requests/action_controller_metrics_spec.rb

@@ -74,8 +74,9 @@
 
     expect_metric(
       tags: a_hash_including(
-        method: "ExceptionsController#index",
-        hook:   "process_action"
+        method:    "ExceptionsController#index",
+        hook:      "process_action",
+        exception: "ZeroDivisionError"
       )
     )
   end