More meaningful debug for "No valid credential sources found for AWS Provider" intermittent issues

[lifeofguenter]

There have been quite some issues in the past with intermittent errors "No valid credential sources found for AWS Provider":

• intermittent "No valid credential sources found for AWS Provider" error #590
• provider-aws: Intermittent Race Condition with Ec2 Metadata service/credentials terraform#6222
• Regression between 0.12.24 and 0.12.29 on ec2metadata calls terraform#25835

Unfortunately the error message, even with TF_LOG=TRACE, is not very helpful:

It would be great for debugging, if the TRACE logs could show actual payload (request + response with headers) that directly involved the decision for throwing that error.

That would greatly help us determine if there was a intermittent connectivity issue, or if we were indeed being rate limited, or any other issue we have not even thought of.

[lifeofguenter]

Closing this ticket:

1. in 0.13 the error message has been improved drastically, now showing an actual error (instead of just saying "credentials did not work out"):

[2020-08-29T09:06:42.569Z] Error: RequestError: send request failed
[2020-08-29T09:06:42.569Z] caused by: Post "https://sts.amazonaws.com/ ": net/http: TLS handshake timeout
[2020-08-29T09:06:42.569Z] 2020/08/29 09:06:42 [ERROR] eval: *terraform.EvalSequence, err: error configuring Terraform AWS Provider: no valid credential sources for Terraform AWS Provider found.
[2020-08-29T09:06:42.569Z] 
[2020-08-29T09:06:42.569Z] Please see https://registry.terraform.io/providers/hashicorp/aws 
[2020-08-29T09:06:42.569Z] for more information about providing credentials.

2. This was highly likely a similar issue to Intermittent network issues (read: connection reset Errors) #14163 - which since seems to have been resolved by AWS as we are not seeing these type of issues anymore lately.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!