A Minimal Docker image with a C++ gRPC server.

This project shows how to create a minimal Docker image containing a C++ gRPC service.

Requirements

Operating System

This demo is intended for Linux systems only. It may work on other operating systems using some form of virtual machine, but I have not tested it.

Docker

You must have Docker installed on your workstation. I have only tested the Docker files with 18.09, but any version greater than 17.05 should work.

Create devtools Docker image

First we create a Docker image with all the development tools necessary to compile the gRPC server. While it is possible to install all these development tools in your workstation, a Docker image makes the remaining steps easier to reproduce.

This step may take a few minutes, even a couple of hours, as it builds gRPC and other dependencies. For reference, it took 1h:50m to build the image while running in a development laptop configured with a Core i5 8th Gen processor and 16GB of RAM.

sudo docker build -t grpc-cpp-devtools:latest -f tools/Dockerfile.devtools tools

Create the server Docker image

Once the development tools image is created we can use it to create a Docker image with a C++ gRPC server:

sudo docker build -t grpc-cpp-echo:latest -f examples/echo/Dockerfile.server .

Note that this image is created for the echo example. Besides, you can easily build images for other examples you place into the examples directory by using the same naming pattern of the echo example. For instance, we have built another, filetransfer example whose server you can built with the command below:

sudo docker build -t grpc-cpp-filetransfer:latest -f examples/filetransfer/Dockerfile.server .

However, we continue only by building the echo example image to keep it simple.

Note also that the images are relatively small:

sudo docker image ls grpc-cpp-echo:latest

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
grpc-cpp-echo       latest              04d95e5adaa6        4 minutes ago       14.6MB

Run the server in the Docker image

For general behavior, use docker run to start a container using this image. You may want to detach from the image using the -d option and capture its id so you can terminate it later:

ID=$(sudo docker run -d -P grpc-cpp-echo:latest /r/echo_server)

Using bind mounts

Note that the filetransfer example might use the files folder in the root of the project as a bind mount directory. This uses a synchronized (two-ways directory) that you can run as below in Windows PowerShell:

docker run -d -P -v "${PWD}\files:/app/files" grpc-cpp-filetransfer:latest /r/filetransfer_server

Note the mapping of port 7000 to the localhost to ease testing.

Use the client to test connectivity

The image also contains a small client to demonstrate connecting to it:

ADDRESS=$(sudo docker port "${ID}" 7000)
sudo docker run --network=host grpc-cpp-echo:latest /r/echo_client --address "${ADDRESS}"

Terminate the container

sudo docker kill "${ID}"