## Changes

[osamahassani05355881581]

Changes

If we have multiple metahook instances, let's not generate multiple temporary directories; instead just create one (and only dump the environment variables once). We also shard the vars file by the plugin configuration (calculating a hash using the standard cksum utility) so that you can have multiple metahook instances each with their own configuration (which is implicitly stored in the vars file).

I'm not sure why the vars file is created at all, as it seems it could be dynamically probed with [[ -v "BUILDKITE_PLUGIN_METAHOOK_${upperd}" ]] instead of using the grep on the vars file (since the variables should be live in the environment when the hook is actually executed), but I kept the current behavior.

Verification

This fixed an issue with multiple metahook instances in a pipeline of mine.

Originally posted by @staticfloat in improbable-eng/metahook-buildkite-plugin#12