My current primary tech stack is Node.js/Javascript and, like many teams, I moved our development and production environments in to Docker containe...
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I'd suggest replacing
npm installwithnpm cifor faster builds in your node Dockerfile 🤔Tried npm ci and got the bug which has not fixed yet github.com/npm/npm/issues/21007. So can't use it. Tested it on simple configuration - works well, but because of the bug can't use it with unified dev/prod configs. Will wait once they fix it and then test it properly. Especially weird that PR is already submitted with the fix, but nobody is even replied about the plans of merging it.
Huh, that's an annoying bug.
Why would you want to have
node_modulesas a volume though? 🤔When you mount app to the container it overrides completely destination folder, so your installed during build modules will be vanished. I want to keep them so use that hack to exclude node modules folder. Did not find any better solution for the time being.
I get that (we usually even add
node_modulesto.dockerignoreto evade cross-platform compat issues). I'm just not entirely sure why you'd want to havenode_modulesas a volume since you runnpm installduring image build anyway. Am I missing something? 🤔.dockerignore only works on copy/add command during build time. But when you mount a folder it will override everything which were copied/installed to the container during the build.
it gives you 3 options:
But you are using
COPYin the example Dockerfiles in the article - that's what confuses me 😅Or are you talking about using pre-built docker image for development using local code? Then it makes sense, but the whole approach is indeed quite cumbersome 🤔
Goal: get a Dockerfile which fit for development on local machine.
Requirements: App should not rely on anything at your local machine despite of Docker installation and the app code.
For node.js app you need to have installed node_modules. So we need install it somewhere and it comes to the 3 points in the previous comment.
So, we happy to do npm install in Dockerfile because that good for both development and production environments. By default node_modules installs at the same as your app directory folder in our case /usr/src/app/node_modules. Modules installed during the build. Then because development on local machine requires that your changes in the code reflect on the app inside docker we mount our local folder with the app(where we don't have node_modules) to the container. It overrides the /usr/src/app in the container and app will not start without node_modules. To use node_modules which were installed during the build-time, there is a hack of using volume as described in stack overflow.
Ah, I finally get it! 😅
Thanks for the detailed explanation!
Thanks a lot, that's why I'm writing articles :) because it's possible to get a feedback. Never heard about npm ci, reading about it now and going to check it over the weekend.
Any idea why my
node-modulesin empty? 🤔 It annoys my IDE a lot 😅Edit: fixed it with this approach => stackoverflow.com/a/61137716/8966651
Same problem here
Thanks. This is what I was looking for. Having node_modules also available on the host is essential for development.
Thanks for the article. On my own, I'm already using Docker that way but I still didn't figure out the best way to have the node_modules folder available on the host and having my IDE working with for the autocomplete and more. (For TypeScript, for example, it's better to get the type from packages)
So I found a way during the install process, I have to install on my own the package locally but both node_modules could be different if my node version is different from my machine and the container, so it's already an issue here... And I know it's not how Docker is designed for but in this case, it could really be nice to have the files available.
Any idea? :)
The only way I've found to solve that => stackoverflow.com/questions/510976...
Hi, great article! Thanks for sharing your knowledge with us.
I have a doubt about best practices for handling environment variables.
Reading your Dockerfile, i felt a little strange seeing
NODE_ENV=developmentin builder andstart:prodlater on. I would expect one environment to be the 'default' and the other one would have to override what is needed. But I didn't see it in here, is the default one 'development' or 'production'?I understand
npm installworks based on NODE_ENV variable, so whether development or production, it will work as expected.Is there a similar solution for
npm start? To run the correct command based on NODE_ENV variable?you can have your npm scripts like :
start:developmentandstart:productionIn the Dockerfile, you can use
CMD [ "npm", “run”, "start:${NODE_ENV}" ].Hi, I have the same doub, if you have found a solution, please shared it, I would appreciate.
If someone gets the following error on a SELinux-enabled machine (such as Fedora GNU/Linux):
change this:
to this:
This took some time to figure out, be sure to thank Stack Overflow ;)
Oh. My. God.
Thank you. I was close to literally pulling my hair out.
Hi Alex, thanks for the excellent article.
I am developing something similar at work and I have a question regarding docker compose and shared volumes that I hope you could help me with.
Basically I designed the Docker Environment so the web application was split up between code and a proxy server (nginx).
The container holding the code creates a shared volume, and then the container running Nginx serves its contents.
I made it this way so it would be easier in the future to replace Nginx with other servers (e.g. Apache).
Now my question is: do you think it is appropriate to initialize the container holding the code as a
servicein thedocker-composefile? Its purpose is only to create the shared volume (it stops immediately after that).I am sorry if this comes across as a very noob question but I didn't find anything against or in favor of this approach.
Thank you,
Gabriel
Hi Gabriel,
I'm not quite sure that I understood what's exactly in your service. For example if it's something like webpack/gulp website you build and then use that built data as a part of a nginx container I don't see any problem with that.
I also have in my microservices docker compose file for one project, one service which I execute with empty command, because I have to built and then use some commands through it via docker-compose run
That's exactly it. It is a container that only compiles the code via webpack/grunt.
Thanks!
Although I agree Docker-Compose is the best local orchestration, Kubernetes reigns supreme for container orchestration. You should give that a shot next if you haven't already. Will make your deployments so much easier.
We already use Kubernetes at productoin, docker-compose for development envs. Kubernetes now is another trend which hard to avoid.
Could you follow up with an article on Kubernetes? That would be awe because you explained things really well. Docker looks so easy, but it’s not and i learned lots from you tonight. Super appreciate all your effort!
Hi Alex, great stuff, I've been working on something similar in my company for a quite while. Wanted to ask you one more thing on subject of your article. Could you get all Win, Linux & Mac based developers to use your docker based dev environment?
Nice article Alex. Good to see other people care about environmental parity / Docker is not just for production. A couple points to share:
"...Replace CMD with the command for running your app without nodemon..." Checkout this article concerning ENTRYPOINT vs CMD. I found it super helpful, especially when writing my own images and need to change the execution command.
I look forward to your next article, keep up the good work!
Link doesn’t work and I dug for the article on my iPad and couldn’t find it either. Any suggestions or alternatives?
Hi Alex,
I went through your tutorial, and all the steps went well. However, I got into a problem. When I build my production docker-compose file before the development docker-compose file, the app image could not find nodemon in it. If I build the development before the production, all the development modules are available in app image, and nodemon is available as well. Is it supposed to be so? Or did I miss something?
And another question, how to you install new dependencies in your images?
Hey Alex, thank you for the article, it's helped me get up and running with node/docker better than any other article so far. I'm brand new to Docker so a lot of this is still kind of confusing to me. Was hoping to get a few questions answered.
1) If using yarn, does it need to be installed into the Docker container first? I switched out npm with yarn in the examples you gave and it worked fine, but I don't know if it's just because I have yarn installed globally on my pc.
2) I don't really get the concept of having a Dockerfile (which you said we're supposed to set up best for both prod and dev environments) and a docker-compose file. If the docker-compose is used for dev, why does the dockerfile have to be configured for dev? I don't really understand when and how each of them are used relative to eachother.
3) While developing, do you have to continually rebuild the image as you add dependencies?
Thank you for your time and for the article, much appreciated!
Hey @ohryan
1) yarn is the part of node docker image, that why it works for you
2) Actually I'm proposing try to unify Dev and prod dockerfiles if that's possible. In most of projects I worked in, they could be easily be the same
3) That's only one downside, after changing you dependencies you have to rebuild the image. Fortunately it mostly actively happens at the beginning of the project. But it always depends on your docker compose configuration, for example in my example goal was to make sure we only rely on docker on local machine, but with small changes you could change that approach to installation of node modules on local machine and then use them with docker.
dev.to/alex_barashkov/comment/8a92
"install node modules in a custom directory that also described by the link above"
And why not to use this solution?
IMHO, it sounds better for me. As it aligns with:
1) Docker best practices, for me it is more a volume data rather than app dependencies.
2) Your node modules are explicitly available and you could check source code for them without a problem.
3) All node modules are going to be installed similar way as without docker. Personally, it is more a plus, as without docker we've used the same way and docker is more for the managing system dependencies. As I say, IMHO.
Hi, thanks for to post, in windows nodemon no working, you have propagation file change with nodemon --legacy-watch src/index.js
stackoverflow.com/questions/392396...
My experience with this on larger projects is that the file share between OSX and the docker VM is too slow for development. You'll probably have to change of file share at some point. To solve this I ended up installing docker in a vagrant VM and using nfs (nfs server running from the Linux VM) to share the files.
Thx for the tips - very useful to setup effective dev configuration :)
I find out that using nodemon inside the container works but slow on every change.
I can use it anyway but it's slow, how do you work with that?
Locally nodemon shines.