log: change log format to JSON payload for better log in Stackdriver (#66)

change the log format in Python and Node.js services.

Effected services are currencyservice, emailservice, paymentservice,
and recommendationservice. Loadgenerator is left as is because of
the diffculty to change the log format and log target in locust.

ref. #47

src/emailservice/email_client.py

@@ -19,6 +19,9 @@ import grpc
 import demo_pb2
 import demo_pb2_grpc
 
+from logger import getJSONLogger
+logger = getJSONLogger('emailservice-client')
+
 # from opencensus.trace.tracer import Tracer
 # from opencensus.trace.exporters import stackdriver_exporter
 # from opencensus.trace.ext.grpc import client_interceptor
@@ -39,10 +42,10 @@ def send_confirmation_email(email, order):
       email = email,
       order = order
     ))
-    print('Request sent.')
+    logger.info('Request sent.')
   except grpc.RpcError as err:
-    print(err.details())
-    print('{}, {}'.format(err.code().name, err.code().value))
+    logger.error(err.details())
+    logger.error('{}, {}'.format(err.code().name, err.code().value))
 
 if __name__ == '__main__':
-  print('Client for email service.')
+  logger.info('Client for email service.')

src/emailservice/email_server.py

@@ -50,6 +50,9 @@ from grpc_health.v1 import health_pb2_grpc
 # except:
 #     pass
 
+from logger import getJSONLogger
+logger = getJSONLogger('emailservice-server')
+
 # Loads confirmation email template from file
 env = Environment(
     loader=FileSystemLoader('templates'),
@@ -78,14 +81,14 @@ class EmailService(BaseEmailService):
         "from": {
           "address_spec": from_address,
         },
-        "to": [{ 
-          "address_spec": email_address 
+        "to": [{
+          "address_spec": email_address
         }],
         "subject": "Your Confirmation Email",
         "html_body": content
       }
     )
-    print("Message sent: {}".format(response.rfc822_message_id))
+    logger.info("Message sent: {}".format(response.rfc822_message_id))
 
   def SendOrderConfirmation(self, request, context):
     email = request.email
@@ -95,7 +98,7 @@ class EmailService(BaseEmailService):
       confirmation = template.render(order = order)
     except TemplateError as err:
       context.set_details("An error occurred when preparing the confirmation mail.")
-      print(err.message)
+      logger.error(err.message)
       context.set_code(grpc.StatusCode.INTERNAL)
       return demo_pb2.Empty()
 
@@ -111,7 +114,7 @@ class EmailService(BaseEmailService):
 
 class DummyEmailService(BaseEmailService):
   def SendOrderConfirmation(self, request, context):
-    print('A request to send order confirmation email to {} has been received.'.format(request.email))
+    logger.info('A request to send order confirmation email to {} has been received.'.format(request.email))
     return demo_pb2.Empty()
 
 class HealthCheck():
@@ -131,7 +134,7 @@ def start(dummy_mode):
   health_pb2_grpc.add_HealthServicer_to_server(service, server)
 
   port = os.environ.get('PORT', "8080")
-  print("listening on port: "+port)
+  logger.info("listening on port: "+port)
   server.add_insecure_port('[::]:'+port)
   server.start()
   try:
@@ -142,5 +145,5 @@ def start(dummy_mode):
 
 
 if __name__ == '__main__':
-  print('starting the email service in dummy mode.')
+  logger.info('starting the email service in dummy mode.')
   start(dummy_mode = True)

src/emailservice/logger.py

@@ -0,0 +1,40 @@
+#!/usr/bin/python
+#
+# Copyright 2018 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import sys
+from pythonjsonlogger import jsonlogger
+
+# TODO(yoshifumi) this class is duplicated since other Python services are
+# not sharing the modules for logging.
+class CustomJsonFormatter(jsonlogger.JsonFormatter):
+  def add_fields(self, log_record, record, message_dict):
+    super(CustomJsonFormatter, self).add_fields(log_record, record, message_dict)
+    if not log_record.get('timestamp'):
+      log_record['timestamp'] = record.created
+    if log_record.get('severity'):
+      log_record['severity'] = log_record['severity'].upper()
+    else:
+      log_record['severity'] = record.levelname
+
+def getJSONLogger(name):
+  logger = logging.getLogger(name)
+  handler = logging.StreamHandler(sys.stdout)
+  formatter = CustomJsonFormatter('(timestamp) (severity) (name) (message)')
+  handler.setFormatter(formatter)
+  logger.addHandler(handler)
+  logger.setLevel(logging.INFO)
+  return logger

src/emailservice/requirements.txt

@@ -32,10 +32,11 @@ pycairo==1.17.1
 pycparser==2.19
 pycrypto==2.6.1
 PyGObject==3.30.1
+python-json-logger==0.1.9
 pytz==2018.5
 pyxdg==0.26
 requests==2.19.1
 rsa==4.0
 SecretStorage==3.1.0
 six==1.11.0
-urllib3==1.23
+urllib3==1.23