FEATURE: Allow Unicorn logs to be JSON formatted.

spec/components/unicorn/unicorn_json_log_formatter_spec.rb

@@ -0,0 +1,31 @@
+require 'rails_helper'
+require 'unicorn/unicorn_json_log_formatter'
+
+RSpec.describe UnicornJSONLogFormatter do
+  context 'when message is an exception' do
+    it 'should include the backtrace' do
+      freeze_time do
+        begin
+          raise 'boom'
+        rescue => e
+          error = e
+
+          output = described_class.new.call(
+            'INFO',
+            Time.zone.now,
+            '',
+            e
+          )
+        end
+
+        output = JSON.parse(output)
+
+        expect(output["severity"]).to eq('INFO')
+        expect(output["datetime"]).to be_present
+        expect(output["progname"]).to eq('')
+        expect(output["pid"]).to be_present
+        expect(output["message"]).to match(/boom:.*/)
+      end
+    end
+  end
+end