Node Code - hello express on docker
I got my "Hello Express" example working on Docker for Windows. I see the potential benefit of putting a (node) app in docker, but am I meant to actually develop this way? It seems like a lot of steps to create a package each time I change code. There must be something I'm missing: please leave a comment to let me know.
I also took the time to update the version of Node I was using. It was painless: I uninstalled the old version and used choco install nodejs. This installed node 6.2.2 (code named "slim"?) and npm 3.9.5. I ran my hello world and hello express code, and they still worked fine.
To start with, I created a brand new express project:
express hello-express-docker cd hello-express-docker npm install
And then, I opened it with Visual Studio Code.
code .
By the way, you can open up a console window from within Visual Studio Code. View -> Toggle Integrated Terminal (or Ctrl+`).
Next, I pretty much followed the instructions on how to Dockerize a Node.js web app. First, I created a Dockerfile in the hello-express-docker folder. This is just a text file named "Dockerfile". Inside that file, I put:
# I used node:slim which corresponds to 6.2.2 I guess FROM node:slim # Create app directory RUN mkdir -p /usr/src/app WORKDIR /usr/src/app # Install app dependencies COPY package.json /usr/src/app/ RUN npm install # Bundle app source COPY . /usr/src/app # Expose the port EXPOSE 3000 # kick off the express site CMD [ "npm", "start" ]
Note that I used a different port number than the instructions, because that's what express's default seems to be (not 8080 as the instructions indicate).
Next I created a docker package.
docker build . -t ccc/hello-express-docker
The tag isn't strictly necessary; the ccc stands for "Cross Cutting Concerns" :)
Once that's done, you can list all the images you have with:
docker images
I have some other images that I downloaded from the docker hub, including couchbase, nginx, ubuntu. You should see at least the ccc/hello-express-docker package listed.
Now that I have an image, I'll run it just like any other docker image:
docker run --name hello_express_docker -p 49160:3000 -d ccc/hello-express-docker
Port 49160 is just an arbitrary port. Once that's running, I can visit my site in a browser: http://docker:49160 (docker is the host name that Docker for Windows uses. If you are using Mac, Linux, Docker Toolbox, etc that may vary).
And that's it! Now my hello-express site is running in a container. If I were done, I guess I could give this container to devops for deployment. I'm struggling to see why I would do this on a day-to-day basis as a developer. Maybe I can have the docker container "mount" my working folder so I can make changes with Visual Studio Code. Or vice versa?
