Automatic runtime install of tools

[rarkins]

An even more advanced approach here would be that we create our own tools directory in $PATH, e.g. containing node, poetry, gradle, etc. But each is in fact a wrapper/stub and its purpose is to dynamically install the required tool + language and then pass the same parameters to the tool itself after it's installed.

e.g. the application like Renovate will simply call poetry via child process, which then kicks off:

• Our own custom shell script
• Installs python if missing (According to PYTHON_VERSION)
• Installs poetry
• Calls newly installed poetry and passes all args to it

Depends on

• Allow runtime install of tools #16
• Switch from bash scripts to higher language #771
• Support install-tool without associated version or env variable #1384
• Support tool version auto detection #1385

[viceice]

I think for this we need a higher language to make this more easy.

I suggest to use pkg and package some node tools.
Use the executable name to differenciate the mode to run, eg: prepare-tool, install-tool, install-npm, install-buildpack

[viceice]

@rarkins Do we still like to do this?

When such a wrapper is called and a version is passed via env, use that version.
If version is not set use latest version or fail?

[rarkins]

Yes, we need this for other products at Mend. Except we also want it to do it's own auto detection too, for the tools which don't have the smarts like Renovate

[viceice]

ok, detecting tool version from current dir (until repo root) will be tricky. so i'm sure it's nothing we should try to do in bash scripts.

[rarkins]

My plan is to do it first using TS so that we can reuse renovate's datasource lookup logic. It can be compiled to a binary using pkg. After that porting to Go is a nice to have. I don't think this forces the current code to be rewritten in the same time frame and can remain as bash

[viceice]

sounds good.

#771 (comment)

[viceice]

btw: PIPENV_VERSION can't be used¹²

Footnotes

1. https://github.com/pypa/pipenv/issues/3633#issuecomment-478250721 ↩

2. https://github.com/pypa/pipenv/issues/5627 ↩

[rarkins]

Can it be unset before we call to pipenv?

[viceice]

maybe, not working on it now.