S3-compliant services (DigitalOcean spaces et al.)

[joonas-fi]

• Add UI for specifying non-AWS endpoints
• Add docs to: https://function61.com/varasto/docs/storage/s3/

Current config UI:

[joonas-fi]

This boilerplate (for github.com/aws/aws-sdk-go) works for DigitalOcean Spaces:

    config := &aws.Config{
        Endpoint: Pointer("fra1.digitaloceanspaces.com"),
        Region:   Pointer("fra1"),
    }

    if accessKeyId != "" {
        config.WithCredentials(credentials.NewStaticCredentials(accessKeyId, accessKeySecret, ""))
    }

    sess, err := session.NewSession(config)
    if err != nil {
        return nil, err
    }

    return s3.New(sess), nil

Looking at above screenshot, we support already configuring Region ID so all thats' missing is the endpoint.

Summary: let's support specifying the endpoint. That should unlock DigitalOcean and other 3rd party services.

[joonas-fi]

The above described implementation works:

Instructions

You get something like from DigitalOcean as bucket endpoint https://mybucket.ams3.digitaloceanspaces.com. This means you configure to Varasto:

• Bucket = mybucket
• Region = ams3
• Endpoint = ams3.digitaloceanspaces.com