Take this Mochitest job:

https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=246999672&repo=autoland&lineNumber=10975

When trying to open the screenshot.png artifact I get an "AccessDenied" error:

https://queue.taskcluster.net/v1/task/FRLKJGB9RdawH8encMnUHw/runs/0/artifacts/public/test_info/mozilla-test-fail-screenshot_7TcYKb.png

AccessDeniedAccess Denied73B5DD0FBBC542E9iKRi1gs3n2KVpzGAaDNvURQcrk34FC2qKaPVf3G9UAYtxaD1pLzMe6YqKMk2E+RFaGLENO+KdzI=

Geoff, not sure if it is related to uploading, or a taskcluster problem. Could you check and move appropriately? Thanks.

I don't know what the issue is. I'm happy to take it back as a Testing : General bug if there is a problem with the artifact creation, but probably best for taskcluster folks to figure this out.

I'm guessing that there was an issue uploading that artifact, as the other artifacts seem fine. "AccessDenied" is S3's way of showing a 404 error. I can see if I can find more logging.

Just for reference here the line from the job's full log:

[taskcluster 2019-05-17T09:48:29.870Z] Uploading artifact public/test_info/mozilla-test-fail-screenshot_7TcYKb.png from file build/blobber_upload_dir/mozilla-test-fail-screenshot_7TcYKb.png with content encoding "", mime type "image/png" and expiry 2020-05-16T09:17:49.689Z

There is no explicit failure visible.

May 17 03:01:43 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: 0#012#011
May 17 03:01:43 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: #012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: 2019/05/17 10:03:07 Request
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: 2019/05/17 10:03:07 PUT /FRLKJGB9RdawH8encMnUHw/0/public/test_info/mozilla-test-fail-screenshot_7TcYKb.png?AWSAccessKeyId=AKIAJTPURLXKI2RSRWOQ&Content-Type=image%2Fpng&Expires=1558089219&Signature=rCnhCu2KIdXubfk8iiSE9YzYOwY%3D HTTP/1.1#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Host: taskcluster-public-artifacts.s3.us-west-2.amazonaws.com#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: User-Agent: Go-http-client/1.1#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Content-Length: 0#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Content-Type: image/png#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Accept-Encoding: gzip#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: #012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: 2019/05/17 10:03:07 Error: (Intermittent) HTTP response code 501
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: HTTP/1.1 501 Not Implemented#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Connection: close#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Transfer-Encoding: chunked#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Content-Type: application/xml#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Date: Fri, 17 May 2019 10:03:07 GMT#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: Server: AmazonS3#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: X-Amz-Id-2: tXG0UQKuHAeL6ycQqGxXQ9MhwgFiFuiECv5o0V8YCrO8GG3Y8K1GTh4/9+D0F7i4h56XJ4+pqOU=#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: X-Amz-Request-Id: B7693A157CC01ADB#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: #012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: 14d#012#011
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: <?xml version="1.0" encoding="UTF-8"?>
May 17 03:03:07 t-yosemite-r7-386.test.releng.mdc1.mozilla.com generic-worker: <Error><Code>NotImplemented</Code><Message>A header you provided implies functionality that is not implemented</Message><Header>Transfer-Encoding</Header><RequestId>B7693A157CC01ADB</RequestId><HostId>tXG0UQKuHAeL6ycQqGxXQ9MhwgFiFuiECv5o0V8YCrO8GG3Y8K1GTh4/9+D0F7i4h56XJ4+pqOU=</HostId></Error>#012#011 

(this is generic-worker 13.0.3)

https://github.com/aws/aws-sdk-js/issues/15#issuecomment-11666354 suggests that maybe this is due to the empty file. I do see Content-Length: 0 in the headers above. Perhaps that header must be omitted in the case of an empty file?