Configurable cache directory

[calvinbui]

Thanks for creating an issue! Please fill out this form so we can be
sure to have all the information we need, and to minimize back and forth.

• What are you trying to do?
  Set a unique cache directory

• What feature or behavior is this required for?
  Caching results between runs

• How could we solve this issue? (Not knowing is okay!)
  I believe this will need some changes: https://github.com/sonatype-nexus-community/go-sona-types/blob/a618cf1b0a4b00832ff05cd83f16114d5bc43c48/ossindex/internal/cache/cache.go#L67

• Anything else?

cc @bhamail / @DarthHater

[bhamail]

Thanks for creating this issue. Could you elaborate on your use case for this? I'm just trying to understand the details.

[calvinbui]

Speeding up CI builds

[ihavespoons]

Putting a plus 1 on this issue. I am trying to run this out of a Lambda function and the dependent library https://github.com/sonatype-nexus-community/go-sona-types/ causes a critical error because its using usr.HomeDir to determine home directory. Unfortunately this relies on /etc/passwd and ignores the $HOME variable. This means this software is essentially impossible to run in a Serverless environment.

[DarthHater]

@calvinbui @ihavespoons I'll see if I can jet this through today!