Allow to change engine directory

Problem

I’m trying to integrate prisma with Bazel, but the main problem is that prisma downloads engine to /home/xnerhu/.cache/prisma/master/2452cc6313d52b8b9a96999ac0e974d0aedf88db/debian-openssl-1.1.x/libquery-engine directory. Bazel is a sandboxed environment and it throws Error: EROFS: read-only file system, which is expected.

Suggested solution

I’m asking to add an option to prisma generate CLI and the others to change path to engine directory.

Additional context

prisma generate --schema ./schema --engine ./engine

[CooperBills]

Done! I managed to get Prisma working with Bazel, and open sourced the rule here: https://github.com/CooperBills/rules_prisma - It’s currently pretty limited (it’s only a single prisma_js_library rule that generates the typescript/javascript client in a bazel-compatible way, but should work as a good starting point if more functionality is needed).

As for how it works, it turns out #3 from my comment above is also already happening, but in the @prisma/engines package (perhaps the prisma cli should check in @prisma/engines before trying to pull from the internet?). So my bazel rule references the engines from @prisma/engines and points the cli to them via environment variables.

[janpio]

(The engine download logic is a bit of a mess - as you might have noticed - and we are working on cleaning that up. Hopefully afterwards this will make a lot more sense and then also be able to be controlled more directly and cleanly.) Thanks for posting the workaround!