Support envfrom secret

[futurelm]

pass env variables use secret
https://pyroscope.slack.com/archives/C01FJRYENPQ/p1668486401890059

similar open issue: #41

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[kolesnikovae]

Thank very much for the contribution @futurelm!

There are some conflicts with the main branch, could you solve them please? Also, I might be mistaken but it seems that README was not generated with helm-docs: please give the contribution guide a look.

Also, I left a couple of notes, and would love to hear your thoughts

[kolesnikovae]

I think envFrom might be misleading as there is k8s directive with the same name already that works slightly differently. Please consider changing .Values.envFrom to .Values.envVars.

Also, it might be better to require a user to provide the full structure rather than forcing them to use predefined secret names like pyroscope-env-secret and to not limit them to secretKeyRefenv var source (there are three more of them)

For example (I did't test it):

values.yaml:

      env:
         KEY: value
      envVars:
      - name: SECRET_USERNAME
        valueFrom:
          secretKeyRef:
            name: mysecret
            key: username
            optional: false
      - name: SECRET_PASSWORD
        valueFrom:
          secretKeyRef:
            name: mysecret
            key: password
            optional: true

deployment.yaml:

           {{- if or .Values.env .Values.envVars }}
           env:
           {{- range $k, $v := .Values.env }}
             - name: {{ $k }}
               value: {{ $v }}
           {{- end }}
           {{- with .Values.envVars }}
           {{- toYaml . | indent 12 }} # Not sure about indent
           {{- end }}
           {{- end }}

[futurelm]

sure, it is better to not limit them to secretKeyRefenv var source, i will update to use toYaml

[kolesnikovae]

It would be great to have a comment here explaining users the difference with env and which option is preferable in a particular case (e.g if one wants to protect sensitive variables)