Greeter (Python)

This code is based on example from gRPC's Python/Getting Started and Connexion’s Quickstart. The gRPC example supports reflection and HTTP example support's the Swagger UI.

Running the Server

Pyenv + Virtualenv

If you want to run on the host, you can run it locally using this:

# create virtual environment for greeter (NOTE: requires pyenv and pyenv-virtualenv)
pyenv virtualenv $PYTHON_VERSION greeter-$PYTHON_VERSION
# set virtual env to greeter's virtualenv
pyenv shell greeter-$PYTHON_VERSION

# install required python modules
pip install -r requirements.txt

# run server
python greeter_server.py

Docker

# build image locally
docker build --tag greeter-server .

# run serer in background
docker run --detach --name greeter_server \
  --publish 9080:9080 --publish 8080:8080 greeter-server:latest

Publishing the Image

export DOCKER_REGISTRY="<your_registry_goes_here>"
docker build --tag greeter-server .
docker tag greeter-server:latest ${DOCKER_REGISTRY}/greeter-server:latest
docker push ${DOCKER_REGISTRY}/greeter-server:latest

Testing the client

Pyenv + Virtualenv

grpcurl -plaintext -d '{ "name": "Michihito" }' localhost:9080 helloworld.Greeter/SayHello
# {
#   "message": "Hello, Michihito!"
# }

curl localhost:8080/SayHello/Michihito
# Hello, Michihito!

Docker

docker run -t --name greeter_client greeter-server:latest \
  curl "<server_address>":8080/SayHello/Michihito

docker run -t --name greeter_client greeter-server:latest \
  grpcurl -plaintext -d '{ "name": "Michihito" }' "<server_address>":9080 helloworld.Greeter/SayHello

The "<server_address>" is the hostname or IP address of the server. So if the server is running outside of the Docker network, then it may be the gateway address, but if it is running within the docker network, then it will be greeter_server or the IP of that server.

Getting Information about API

gRPC Reflection

GRPC_SERVER="localhost"

grpcurl -plaintext $GRPC_SERVER:9080 list
# grpc.reflection.v1alpha.ServerReflection
# helloworld.Greeter
grpcurl -plaintext $GRPC_SERVER:9080 describe helloworld.Greeter
# service Greeter {
#   rpc SayHello ( .helloworld.HelloRequest ) returns ( .helloworld.HelloReply );
# }
grpcurl -plaintext $GRPC_SERVER:9080 describe .helloworld.HelloRequest
# helloworld.HelloRequest is a message:
# message HelloRequest {
#   string name = 1;
# }

OpenAPI

HTTP_SERVER="localhost"
curl $HTTP_SERVER:8080/ui

Testing on Kubernetes

1. Deploy Server and Client:

   export DOCKER_REGISTRY="<your-registry-goes-here>"
   export CCSM_ENABLED="true" # set this ONLY if using consul connect
   
   helmfile --file deploy/helmfile.yaml apply

2. Exec into container:

   GREETER_CLIENT_POD=$(kubectl get pods \
     --selector app=greeter-client \
     --namespace greeter-client \
     --output name
   )
   
   # exec into the container
   kubectl exec --tty --stdin \
     --container "greeter-client" \
     --namespace "greeter-client" \
     $GREETER_CLIENT_POD \
     -- bash

3. Run tests within the container:

   export CCSM_ENABLED="true" # set this ONLY if using consul connect
   
   NS="greeter-server"
   HTTP_SERVER="greeter-server.$NS.svc.cluster.local"
   if [[ "$CCSM_ENABLED" == "true" ]]; then
     GRPC_SERVER="greeter-server-grpc.$NS.svc.cluster.local"
   else
     GRPC_SERVER="greeter-server.$NS.svc.cluster.local"
   fi
   
   # test gRPC
   grpcurl -plaintext -d '{ "name": "Michihito" }' $GRPC_SERVER:9080 helloworld.Greeter/SayHello
   
   # test HTTP
   curl $HTTP_SERVER:8080/SayHello/Michihito