pre-cache node_modules in Docker container

Question

It frustrates me that CI builds for projects which use Node tool chains such as Grunt and Gulp take quite a long time, the bulk of which is consumed by npm install .

I've tried to set up a Docker image, pre-baked with all of the node_module dependencies in the npm cache (each at the same fixed release as declared in my package.json file), but even then the build still takes a few minutes when all it really should need to do is to copy a few directories from the npm cache into my project's node_modules.

I've set cache-min to 9999999, but it still seems to take much longer than it shoul need to.

I've looked local-npm and npm_lazy but they seem over the top, and the former takes ages to install - I suspect that it's trying to download every single npm module in existence - I only need a limited number and don't need to be running a web server to serve them from within the Docker container.

...am I missing something? There must be a faster way to run a CI build...

Answer 1

I was able to get it to work by using .npmrc to point to the npm cache within the docker container. I would suggest you to docker exec into your container and run npm config list | grep cache npm config list | grep cache to ensure that the cache is used.