Elasticsearch: Support for azure credential settings within repository settings

[damianpfister]

Describe the feature:
Allow the Azure Cloud Repo to have configuration settings such as credentials added via an API call rather than in elasticsearch.yml. This will standardise on what is already in place for Amazon S3.

[damianpfister]

Example would be something like:

PUT _snapshot/my_backup2
{
    "type": "azure",
    "settings": {
        "credentials.account": "AZUREACCOUNT",
        "credentials.key": "AZUREKEY"
    }
}

[siddharthlatest]

@damianpfister Second adding this. Does this have any ETA?

[dadoonet]

It does not. Wanna contribute some code?

[liketic]

@dadoonet Seems like the latest s3 plugin has removed those apis?

[dadoonet]

@liketic Yes. I don't think we will support that in the short term but I think that @rjernst has some ideas for the future for "hot reload" or addition of credentials like this.

[darinhoward]

I'd like to add this feature - but seems like Secure Settings pattern may not allow for it 6.x - https://www.elastic.co/guide/en/elasticsearch/reference/6.2/secure-settings.html.

Thoughts ?

[tlrx]

@darinhoward Right, starting from 6.0 we don't allow credentials or sensitive information to be specified in the elasticsearch configuration files or at the repository settings level. All secret information like credentials must be store in the Elasticsearch keystore as a secure setting.

If you look at the documentation (https://www.elastic.co/guide/en/elasticsearch/plugins/current/repository-azure-usage.html), the right way to go is to configure client settings in the keystore and then define the client name in the repository settings.