Introduce configurable blobstore configuration

[tareqmamari]

Add optional blobstore configuration parameter to the values.yaml to
override the default webdav blobstore configuration.

Example:

bits:
  blobstore_config:
    droplets: &droplets_config
      blobstore_type: AWS
      s3_config:
        bucket: your-fancy-bucket-name
        host: s3-endpoint
        access_key_id: <access-id>
        secret_access_key: <access-key>
        region: us-geo
        s3_debug_log_level:
    buildpacks: *droplets_config
    packages: *droplets_config
    app_stash: *droplets_config

Signed-off-by: Matthias Diester matthias.diester@de.ibm.com

Thanks for contributing to Eirini! In order for your pull request to be accepted, we would like to ask you the following:

1. Please base your PR off the develop branch.
2. Describe the change on a conceptual level. How does it work, and why should it exist? Ideally, you contribute a few words to the README, too.
3. Please provide automated tests (preferred) or instructions for manually testing your change.

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this:

https://www.pivotaltracker.com/story/show/164374197

The labels on this github issue will be updated when the story is started.

[cfdreddbot]

✅ Hey tareqmamari! The commit authors and yourself have already signed the CLA.

[mnitchev]

Hi @tareqmamari

We tried deploying the scf helm chart and got this error:

Error: render error in "cf/charts/eirini/templates/bits.yaml": template: cf/charts/eirini/templates/bits.yaml:32:18: executing "cf/charts/eirini/templates/bits.yaml" at <.Values.bits.blobsto...>: can't evaluate field blobstore_config in type interface {}

Could you make the bits configurations optional?
We tried the hasKey function like this:

{{- if hasKey .Values "bits" }}

This worked but maybe having a boolean option like override_bits_blobstore_config and checking that in the if might work better.

BR,
@mnitchev @gdankov

[tareqmamari]

@mnitchev we fixed that, in the latest commit. Having both the flag override_bits_blobstore_config as well as the needed configuration, it is kinda of duplication, we wanted to keep it as compacted as possible.

/CC @HeavyWombat

[petergtz]

@tareqmamari Looks good from Bits-Service perspective too.