Tiny node containers
My favorite language at the moment is javascipt. It's fun & functional!
Since I'm also working quite a bit with docker, I've been frustrated with the size of nodejs docker images. A typical node container holds
npm and all your
dependencies. Add a few
apt-get's and your quickly looking at > 500 MB.
I even started hacking some Go solely for the ability to compile to a single binary.
Until I found nexe...
Building with nexe
Nexe will compile your node app into a single executable binary. No joke! Have a look!
Since we are now compiling, we need to think about things like compile target. Containers run linux. My desktop runs Darwin. A binary compiled on/for Darwin won't be able run inside a container. So, I made a container for compiling apps with nexe.
docker run -v $(pwd):/app -w /app asbjornenge/nexe-docker -i index.js -o app
Granted, nexe is a bit flakey atm. I found two main bugs that I had to work around:
A default package.json somehow messes up the executable.
Workaround: I added a build script that will move package.json to pkg.json, build, then move it back.
When passing arguments to a comiled binary, there must exist a first argument.
Workaround: Just pass a random first argument.
When distributing, we can use the simplest container possible, and just add the binary.
FROM debian:jessie ADD app /usr/bin/app ENTRYPOINT ["app"]
I used this approach to build skylink, check out the difference!
| normal | nexe --------------------------- size | 640.3 MB | 133.6 MB