Unhelpful message on S3 authentication failure

[reinvantveer]

Hope to contribute to your efforts with the following bug report. The entwine merge command can (obviously) fail on unsuccesfully authenticating to a S3-protocol bucket. So, if you have a config.json being

{
    "output": "s3://your_bucket/ept-subsets/",
    "verbose": true,
    "threads": [2, 5],
    "arbiter": {
        "s3": {
            "endpoint": "storage.googleapis.com",
            "access": "wrong",
            "secret": "wrong again!"
        }
    } 
}

the command entwine merge -c config.json exits with:

Encountered an error: Dimension not found: 1
Exiting.

Expected output, something in the order of:

Encountered an error: Authentication failure
Exiting.

---

Using entwine 2.1.0:

root@62be9ee840f1:/app# entwine --version
Invalid app type
    Version: 2.1.0
    Usage: entwine <app> <options>
    Apps:
        build
            Build an EPT dataset
        scan
            Aggregate information about an unindexed dataset
        merge
            Merge colocated entwine subsets
        convert
            Convert an entwine dataset to a different format

[calvinmetcalf]

When I try something similar on 2.1.0 on linux, installed with conda I get Encountered an error: No driver for s3://your_bucket/* when I try to run a build.