Add emailservice

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>

src/emailservice/email_server.py

@@ -0,0 +1,113 @@
+from concurrent import futures
+import argparse
+import os
+import sys
+import time
+
+from jinja2 import Environment, FileSystemLoader, select_autoescape, TemplateError
+from google.api_core.exceptions import GoogleAPICallError
+import grpc
+
+import demo_pb2
+import demo_pb2_grpc
+
+# from opencensus.trace.ext.grpc import server_interceptor
+# from opencensus.trace.samplers import always_on
+# from opencensus.trace.exporters import stackdriver_exporter
+# from opencensus.trace.exporters import print_exporter
+
+# import googleclouddebugger
+
+# try:
+#     sampler = always_on.AlwaysOnSampler()
+#     exporter = stackdriver_exporter.StackdriverExporter()
+#     tracer_interceptor = server_interceptor.OpenCensusServerInterceptor(sampler, exporter)
+# except:
+#     tracer_interceptor = server_interceptor.OpenCensusServerInterceptor()
+
+# try:
+#     googleclouddebugger.enable(
+#         module='emailserver',
+#         version='1.0.0'
+#     )
+# except:
+#     pass
+
+# Loads confirmation email template from file
+env = Environment(
+    loader=FileSystemLoader('templates'),
+    autoescape=select_autoescape(['html', 'xml'])
+)
+template = env.get_template('confirmation.html')
+
+class EmailService(demo_pb2_grpc.EmailServiceServicer):
+  def __init__(self):
+    raise Exception('cloud mail client not implemented')
+    super().__init__()
+
+  @staticmethod
+  def send_email(client, email_address, content):
+    response = client.send_message(
+      sender = client.sender_path(project_id, region, sender_id),
+      envelope_from_authority = '',
+      header_from_authority = '',
+      envelope_from_address = from_address,
+      simple_message = {
+        "from": {
+          "address_spec": from_address,
+        },
+        "to": [{ 
+          "address_spec": email_address 
+        }],
+        "subject": "Your Confirmation Email",
+        "html_body": content
+      }
+    )
+    
+    print("Message sent: {}".format(response.rfc822_message_id))
+
+  def SendOrderConfirmation(self, request, context):
+    email = request.email
+    order = request.order
+
+    try:
+      confirmation = template.render(order = order)
+    except TemplateError as err:
+      context.set_details("An error occurred when preparing the confirmation mail.")
+      print(err.message)
+      context.set_code(grpc.StatusCode.INTERNAL)
+      return demo_pb2.Empty()
+
+    try:
+      EmailService.send_email(self.client, email, confirmation)
+    except GoogleAPICallError as err:
+      context.set_details("An error occurred when sending the email.")
+      print(err.message)
+      context.set_code(grpc.StatusCode.INTERNAL)
+      return demo_pb2.Empty()
+
+    return demo_pb2.Empty()
+
+class DummyEmailService(demo_pb2_grpc.EmailServiceServicer):
+  def SendOrderConfirmation(self, request, context):
+    print('A request to send order confirmation email to {} has been received.'.format(request.email))
+    return demo_pb2.Empty()
+
+def start(dummy_mode):
+  server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))#, interceptors=(tracer_interceptor,))
+  if dummy_mode:
+    demo_pb2_grpc.add_EmailServiceServicer_to_server(DummyEmailService(), server)
+  else:
+    raise Exception('non-dummy mode not implemented')
+  server.add_insecure_port('[::]:8080')
+  server.start()
+  try:
+    while True:
+      time.sleep(3600)
+  except KeyboardInterrupt:
+    server.stop(0)
+
+
+if __name__ == '__main__':
+  print('Starting the email service in dummy mode.')
+  start(dummy_mode = True)