Add error_cause property to log message. (#39)

.rubocop.yml

@@ -13,6 +13,9 @@ Metrics/BlockLength:
   Exclude:
     - spec/**/*.rb
 
+Metrics/ModuleLength:
+  Enabled: false 
+
 Layout/LineLength:
   Max: 120
   Exclude:

lib/sidekiq/exception_utils.rb

@@ -2,25 +2,31 @@
 
 # Utility that allows us to get a hash representation of an exception
 module ExceptionUtils
-  def self.get_exception_with_cause_hash(exc, parent_backtrace = nil, max_depth_left)
-    backtrace = exc.backtrace || []
-    if parent_backtrace
-      common_lines = backtrace.reverse.zip(parent_backtrace.reverse).take_while { |a, b| a == b }
-
-      backtrace = backtrace[0...-common_lines.length] if common_lines.any?
-    end
+  module_function
 
+  def get_exception_with_cause_hash(exc, parent_backtrace = nil, max_depth_left: 1)
     error_hash = {
       'class' => exc.class.to_s,
       'message' => exc.message,
-      'backtrace' => backtrace
+      'backtrace' => backtrace_for(exc, parent_backtrace)
     }
 
     if (cause = exc.cause) && max_depth_left.positive?
       # Pass the current backtrace as the parent_backtrace to the cause to shorten cause's backtrace list
-      error_hash['cause'] = get_exception_with_cause_hash(cause, exc.backtrace, max_depth_left - 1)
+      error_hash['cause'] = get_exception_with_cause_hash(cause, exc.backtrace, max_depth_left: max_depth_left - 1)
     end
 
     error_hash
   end
+
+  def backtrace_for(exception, parent_backtrace = nil)
+    backtrace = exception.backtrace || []
+    if parent_backtrace
+      common_lines = backtrace.reverse.zip(parent_backtrace.reverse).take_while { |a, b| a == b }
+
+      backtrace = backtrace[0...-common_lines.length] if common_lines.any?
+    end
+
+    backtrace
+  end
 end

lib/sidekiq/logging/shared.rb

@@ -54,12 +54,21 @@ def log_job_exception(job, started_at, exc)
 
         config = Sidekiq::Logstash.configuration
         if config.log_job_exception_with_causes
-          payload['error'] = ExceptionUtils.get_exception_with_cause_hash(exc, config.causes_logging_max_depth)
+          payload['error'] = ExceptionUtils.get_exception_with_cause_hash(
+            exc, max_depth_left: config.causes_logging_max_depth
+          )
         else
           exc = exc.cause || exc if exc.is_a? Sidekiq::JobRetry::Handled
           payload['error_message'] = exc.message
-          payload['error'] = exc.class
+          payload['error'] = exc.class.to_s
           payload['error_backtrace'] = %('#{exc.backtrace.join("\n")}')
+          if (cause = exc.cause)
+            payload['error_cause'] = {
+              'class' => cause.class.to_s,
+              'message' => cause.message,
+              'backtrace' => ExceptionUtils.backtrace_for(cause, exc.backtrace)
+            }
+          end
         end
 
         process_payload(payload)

spec/sidekiq/logstash_spec.rb

@@ -120,19 +120,31 @@ def process(worker, params = [], encrypt: false)
     it 'logs the exception with job retry' do
       expect { process(SpecWorker, [true]) }.to raise_error(RuntimeError)
 
-      expect(log_message['error_message']).to eq('You know nothing, Jon Snow.')
       expect(log_message['error']).to eq('RuntimeError')
+      expect(log_message['error_message']).to eq('You know nothing, Jon Snow.')
       expect(log_message['error_backtrace'].split("\n").first).to include('workers/spec_worker.rb:')
+      expect(log_message['error_cause']).to match(
+        hash_including(
+          'class' => 'RuntimeError',
+          'message' => 'Error rescuing error'
+        )
+      )
     end
 
     it 'logs the exception without job retry' do
       allow(SpecWorker).to receive(:get_sidekiq_options).and_return({ 'retry' => false, 'queue' => 'default' })
 
       expect { process(SpecWorker, [true]) }.to raise_error(RuntimeError)
 
-      expect(log_message['error_message']).to eq('You know nothing, Jon Snow.')
       expect(log_message['error']).to eq('RuntimeError')
+      expect(log_message['error_message']).to eq('You know nothing, Jon Snow.')
       expect(log_message['error_backtrace'].split("\n").first).to include('workers/spec_worker.rb:')
+      expect(log_message['error_cause']).to match(
+        hash_including(
+          'class' => 'RuntimeError',
+          'message' => 'Error rescuing error'
+        )
+      )
     end
 
     context 'log_job_exception_with_causes enabled' do