[rush] Should we be able to use the system installed tool?

[davazp]

Please prefix the issue title with the project name i.e. [rush], [api-extractor] etc.

Is this a feature or a bug?

• Feature
• Bug

Please describe the actual behavior.

We are running building our repository inside Docker so we have control about what tool version (yarn in our case) we are using. I would prefer if I could specify something like

yarnVersion: "system"

in rush.json to simplify the build and not need to download yarn again. Is something like this possible? And if it is not, would there be interest on it?

[iclanton]

Can you just preinstall the version of Yarn you're using in your Docker container? Rush looks for cached package managers in $HOME/.rush/node-v<nodeversion>/<toolname>-<version>/. So Yarn 1.17.3 installed for Node 10.15.1 would be installed in $HOME/.rush/node-v10.15.1/yarn-1.17.3/.

If you preinstall Yarn in that folder in your docker container, you should be able to avoid installing Yarn again during your CI. Would that fix your issue?

(Note that Rush also looks for a last-install.flag file with some JSON content in that folder - make sure you include that too)

[davazp]

I was actually just letting rush do it. However, I was building my image with the slim version of the node image and some dependencies to install yarn were missing (like make).

The workaround is to build it with the default docker image, (running rush update) the first time to ensure it's properly cached, and use a multi-stage build to copy the built packages to the slim docker image.

It is more a nice-to-have for me, so feel free to close the ticket if it's not worth the effort 🙂