Merge branch 'add-sentry-logging-to-api' into 'master'

Add Sentry logging to API calls

## What does this MR do?

This MR adds support for Sentry logging in the API.

## Are there points in the code the reviewer needs to double check?

Since the `Grape::Middleware` doesn't have a `params` method, I had to define one using the Rack Request.

## Why was this MR needed?

We are missing a lot of useful errors in the API causing git push/pull errors

## What are the relevant issue numbers?

#21043

See merge request !5882

3 files changed, 36 insertions, 20 deletions

diff --git a/lib/api/api.rb b/lib/api/api.rb
index 6b8bfbbdae6..ecbd5a6e2fa 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -18,22 +18,14 @@ module API
     end
 
     rescue_from :all do |exception|
-      # lifted from https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb#L60
-      # why is this not wrapped in something reusable?
-      trace = exception.backtrace
-
-      message = "\n#{exception.class} (#{exception.message}):\n"
-      message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
-      message << "  " << trace.join("\n  ")
-
-      API.logger.add Logger::FATAL, message
-      rack_response({ 'message' => '500 Internal Server Error' }.to_json, 500)
+      handle_api_exception(exception)
     end
 
     format :json
     content_type :txt, "text/plain"
 
     # Ensure the namespace is right, otherwise we might load Grape::API::Helpers
+    helpers ::SentryHelper
     helpers ::API::Helpers
 
     mount ::API::AccessRequests
diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index d0469d6602d..da4b1bf9902 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -279,6 +279,24 @@ module API
       error!({ 'message' => message }, status)
     end
 
+    def handle_api_exception(exception)
+      if sentry_enabled? && report_exception?(exception)
+        define_params_for_grape_middleware
+        sentry_context
+        Raven.capture_exception(exception)
+      end
+
+      # lifted from https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb#L60
+      trace = exception.backtrace
+
+      message = "\n#{exception.class} (#{exception.message}):\n"
+      message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
+      message << "  " << trace.join("\n  ")
+
+      API.logger.add Logger::FATAL, message
+      rack_response({ 'message' => '500 Internal Server Error' }.to_json, 500)
+    end
+
     # Projects helpers
 
     def filter_projects(projects)
@@ -419,5 +437,19 @@ module API
         Entities::Issue
       end
     end
+
+    # The Grape Error Middleware only has access to env but no params. We workaround this by
+    # defining a method that returns the right value.
+    def define_params_for_grape_middleware
+      self.define_singleton_method(:params) { Rack::Request.new(env).params.symbolize_keys }
+    end
+
+    # We could get a Grape or a standard Ruby exception. We should only report anything that
+    # is clearly an error.
+    def report_exception?(exception)
+      return true unless exception.respond_to?(:status)
+
+      exception.status == 500
+    end
   end
 end
diff --git a/lib/ci/api/api.rb b/lib/ci/api/api.rb
index 17bb99a2ae5..a6b9beecded 100644
--- a/lib/ci/api/api.rb
+++ b/lib/ci/api/api.rb
@@ -9,22 +9,14 @@ module Ci
       end
 
       rescue_from :all do |exception|
-        # lifted from https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb#L60
-        # why is this not wrapped in something reusable?
-        trace = exception.backtrace
-
-        message = "\n#{exception.class} (#{exception.message}):\n"
-        message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
-        message << "  " << trace.join("\n  ")
-
-        API.logger.add Logger::FATAL, message
-        rack_response({ 'message' => '500 Internal Server Error' }, 500)
+        handle_api_exception(exception)
       end
 
       content_type :txt,  'text/plain'
       content_type :json, 'application/json'
       format :json
 
+      helpers ::SentryHelper
       helpers ::Ci::API::Helpers
       helpers ::API::Helpers
       helpers Gitlab::CurrentSettings