Create a mock server and Dockerize it

I was reading the Docker documentation on their website when I came across this incredibly simple technique to replicate an API with only a few lines of code.The mocking server's name is Ronin.js, and it listens on port 8000 by default, according to the documentation.

Note: I'll be dockerizing this project to add some frosting to the cake. 😊

LET ME ...

const ronin = require("ronin-server");
const mocks = require("ronin-mocks");

const server = ronin.server();

server.use("/", mocks.server(server.Router(), false, true));

// @desc    Home page
// @route   GET  /
// @access  Public
server.get("/", (req, res) => {
  res.send("home page");
});

// @desc    Create post
// @route   POST  /
// @access  Public
server.post("/post", (req, res) => {
  const { data } = req.body;
  res.send(data);
});

server.start(() => {
  console.log("app running on mock server");
});

Result

---

Adding docker

Stop the running process in the terminal with 'ctrl C' and add a docker file with 'touch Dockerfile'.

We add a number of commands to the docker file. For greater instruction, I've commented the code.

# Base image we would like to use for our application.
FROM node:17-alpine

# Environment variable which an application is running
ENV NODE_ENV=production

# Working Directory instructs Docker to use this path as the default location for all subsequent commands.
WORKDIR /app


# Copy package.json and package-lock.jsono into our images
#  The COPY command takes two parameters: src and dest. 
# The first parameter src tells Docker what file(s) you would like to copy into the image. 
# The second parameter dest tells Docker where you want that file(s) to be copied to.
# This allows us to take advantage of cached Docker layers. 
COPY ["package.json", "package-lock.json*", "./"]


# execute the command npm install 
# works exactly the same as if we were running npm install locally on our machine
RUN npm install --production


# Add our source code into the image
COPY . .

#  Command that runs the image
CMD [ "node", "server.js" ]

Without comments

FROM node:17-alpine
ENV NODE_ENV=production
WORKDIR /app
COPY ["package.json", "package-lock.json*", "./"]
RUN npm install --production
COPY . .
CMD [ "node", "server.js" ]

---

Add .dockerignore file

If you're used to developing node apps with .gitignore, this will be a breeze. The .dockerignore and the .gitignore are somehow similar. It simply ignores certain files from being pushed to our remote server.
Add node_modules to the .dockerignore file

Build

Last we build our app
docker build --tag node-docker .
The —tag or -t option is used to give images a name tag for easy identification.
Docker build --tag [your docker registry name]/[docker image name to create]:[the version] [Path to build] is the standard.
The . is the current directory in our scenario.

Result:

Now let's run our app

docker run --name docker_tut_mocker_server -p 6767:8000 -d node-docker.

6767:8080 === Local Port : Container Port

-d means run in detached mode
-p means port mapping (i.e map port 6767 to port 8000)
--name flag means rename this image name to [docker_tut_mocker_server]

So, if I write localhost:6767 into my browser. I will get:

Conclusion

Feel free to work around it by using it for CRUD operations in situations when setting up a server would be excessive for a test or small project and dockerize it.

Resource

Click Here