Health check, updates

* Added the grpc_health module for basic health check functionality
* Updated to latest gprc libs

Dockerfile

@@ -1,9 +1,15 @@
 FROM python:3.7.4-alpine3.10
-RUN apk add --no-cache build-base
 RUN mkdir /app
 WORKDIR /app
+RUN apk add --no-cache curl
+RUN curl -O -fssL https://github.com/grpc-ecosystem/grpc-health-probe/releases/download/v0.3.0/grpc_health_probe-linux-amd64 && \
+    mv grpc_health_probe-linux-amd64 /usr/local/bin/grpc_health_probe && \
+    chmod 755 /usr/local/bin/grpc_health_probe
 COPY requirements.txt /app
-RUN pip install --no-cache-dir -r requirements.txt
+RUN apk add --no-cache --virtual build-deps build-base && \
+    pip install --no-cache-dir -r requirements.txt && \
+    apk del build-deps
+RUN apk add --no-cache libstdc++
 COPY src/ /app/
 RUN python -m grpc_tools.protoc \
     -I. \

requirements.txt

@@ -1,5 +1,6 @@
-grpcio==1.21.1
-grpcio-tools==1.21.1
+grpcio==1.23.0
+grpcio-health-checking==1.23.0
+grpcio-tools==1.23.0
 prometheus-client==0.7.1
-protobuf==3.8.0
+protobuf==3.9.1
 six==1.12.0

src/server.py

@@ -10,6 +10,8 @@
 
 import namer
 
+from grpc_health.v1 import health, health_pb2, health_pb2_grpc
+
 request_metric = Summary(
     'english_full_name_seconds',
     'Time processing EnglishFullName requests')
@@ -71,6 +73,10 @@ def command_args():
 
 def serve(args):
     server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
+
+    health_servicer = health.HealthServicer()
+    health_pb2_grpc.add_HealthServicer_to_server(health_servicer, server)
+
     namer_pb2_grpc.add_NamerServicer_to_server(Namer(), server)
 
     ca_cert = None
@@ -99,11 +105,14 @@ def serve(args):
 
     print('Starting server. Listening on port {}...'.format(args.port))
     server.start()
+    health_servicer.set('', health_pb2.HealthCheckResponse.SERVING)
     try:
         while True:
             time.sleep(86400)
     except KeyboardInterrupt:
-        server.stop(0)
+        health_servicer.set('', health_pb2.HealthCheckResponse.NOT_SERVING)
+        time.sleep(10)
+        server.stop(1)
 
 
 if __name__ == '__main__':