python boto3 connection error with no apparent cause

Question

I'm hitting an error with code that connects to AWS using boto3. The error just started yesterday afternoon, and between the last time I didn't get the error and the first time I got the error I don't see anything that changed.

The error is:

botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL:

In .aws/config I have:

$ cat ~/.aws/config
[default]
region=us-east-1

Here's what I know:

• Using the same AWS credentials and config on another machine, I don't see the error.
• Using different AWS credentials and config on the same machine, I do see the error.
• I'm the only one in our group that has this issue for any credentials on any machine.

I don't think I changed anything that would affect this between the last time this worked and the first time it didn't. It seems like I'd have had to change some AWS specific configuration on my side or some low level libraries, and I didn't make any such change. I was talking with a colleague for 30-45 minutes and when I returned and picked up where I left off the issue first appeared.

Any thoughts or ideas on troubleshooting this?

Full exception dump follows.

$ python
Python 2.7.10 (default, Jul 14 2015, 19:46:27) 
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import boto3
>>> boto3.client('ec2').describe_regions()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/botocore/client.py", line 200, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/Library/Python/2.7/site-packages/botocore/client.py", line 244, in _make_api_call
    operation_model, request_dict)
  File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 173, in make_request
    return self._send_request(request_dict, operation_model)
  File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 203, in _send_request
    success_response, exception):
  File "/Library/Python/2.7/site-packages/botocore/endpoint.py", line 267, in _needs_retry
    caught_exception=caught_exception)
  File "/Library/Python/2.7/site-packages/botocore/hooks.py", line 226, in emit
    return self._emit(event_name, kwargs)
  File "/Library/Python/2.7/site-packages/botocore/hooks.py", line 209, in _emit
    response = handler(**kwargs)
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 183, in __call__
    if self._checker(attempts, response, caught_exception):
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 250, in __call__
    caught_exception)
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 273, in _should_retry
    return self._checker(attempt_number, response, caught_exception)
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 313, in __call__
    caught_exception)
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 222, in __call__
    return self._check_caught_exception(attempt_number, caught_exception)
  File "/Library/Python/2.7/site-packages/botocore/retryhandler.py", line 355, in _check_caught_exception
    raise caught_exception
botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL: "https://ec2.us-east-1.amazonaws.com/"

Much

Answer 1

Issue resolved. It turns out that a couple of seemingly unrelated actions independent of anything boto related resulted in HTTP_PROXY and HTTPS_PROXY environment variables being improperly set, which was then breaking the botocore calls under both boto3 and the aws cli. Removing both environment variables resolved the problem.

I'll leave this up as I found it very difficult to find anything pointing to this as a possible cause of this error. Might save someone else some of the hair pulling I went through.

Much

Answer 2

I just had a similar issue. All of a sudden, no connection possible anymore to my s3 through boto3 on django while I had still the possibility to do the actions on my Heroku environment.

Appeared I recently installed the amazon CLI where my configuration was different and the CLI overrules the environment variables... Damn. took me 3 hours to find.

through aws configure I now set

AWS Access Key ID [****************MPIA]: "your true key here without quotes" AWS Secret Access Key [****************7DWm]: "your true secret access key here without quotes" Default region name [eu-west-1]: "your true region here without quotes" Default output format [None]: [here i did just an enter in order not to change this]

Just posting this for the sake of anyone having this issue.

Indefeasible

Answer 3

I came across same error when my connection went down - botocore.exceptions.EndpointConnectionError: Could not connect to the endpoint URL: "https://ec2.us-east-2.amazonaws.com/"

When connection is restored then it worked without any issue. Probable reason for this error could be

1. Connection error
2. Region is not available to cater your request as every request hits endpoint on AWS (more detail can be found on https://docs.aws.amazon.com/general/latest/gr/rande.html#billing-pricing )

It seems like Boto3 has matured enough to throw exception for more proper reason of failure to precisely know what is going.

Also if you have any issue related to your config then most of them are encapsulated with ClientError exception.

Tajuanatak