[v0.4.0] Unrecognized storage client dynamodb

[Tzrlk]

Describe the bug
When following the configuration reference, the comment above schema_config.configs[*].store says:

# Which store to use for the index. Either cassandra, bigtable, dynamodb, or
# boltdb
store: <string>

However, when running loki with dynamodb as the client, the following message is sent to the logs:

level=error ts=2019-11-19T00:52:11.372697769Z caller=main.go:65 msg="error initialising loki" err="error initialising module: table-manager: Unrecognized storage client dynamodb, choose one of: aws, cassandra, inmemory, gcp, bigtable, bigtable-hashed"

To Reproduce
Steps to reproduce the behavior:

1. In an aws dynamodb-backed deployment, set the schema config store type to dynamodb as per the documentation.

Expected behavior
Starting up and using the dynamodb config was expected.

Environment:

• Infrastructure: Kubernetes, EKS, AWS
• Deployment tool: Helm

Screenshots, Promtail config, or terminal output

[slim-bean]

Hey @Tzrlk, it looks like that comment is wrong :(

https://github.com/cortexproject/cortex/blob/ed7c302fd96892b1c4c822a6ccd60317fde51c00/pkg/chunk/storage/factory.go#L182

Looks like you would need to use aws

This is confusing, will leave this issue open to see if we can tidy this up some.