# Type of request: This is a ...

[*] bug report
[ ] feature request

# Detailed description

Perhaps not a bug report per se, but this affected me at least. A new version of `lambci/docker-lambda` was pushed recently. [This commit](https://github.com/lambci/docker-lambda/commit/7ece2742a5b0e84eb09d6ed659f123474e619b27) removed hardcoded defaults for `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`.

I have a lambda that reads a value from secret in `secretsmanager`. If I don't set dummy values for `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` when creating the lambda invoking it will time out reading the secret.

## Expected behavior

A lambda function can read a secret from `secretsmanager`.

## Actual behavior

Lambda times out trying to read secret.

# Steps to reproduce

Create a lambda which tries to read a secret from `secretsmanager` without adding the environments variables mentioned above.

## Command used to start LocalStack

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)

This will work:
```bash
awslocal lambda create-function \
  --function-name foo \
  --runtime go1.x \
  --handler main \
  --role arn:aws:iam::123456790:role/ignore \
  --zip-file fileb://foo.zip \
  --environment "Variables={FOO=bar,AWS_ACCOUNT_ID=123456790,AWS_ACCESS_KEY_ID=0,AWS_SECRET_ACCESS_KEY=0}"
```

This will time out while reading:
```bash
awslocal lambda create-function \
  --function-name foo \
  --runtime go1.x \
  --handler main \
  --role arn:aws:iam::123456790:role/ignore \
  --zip-file fileb://foo.zip \
  --environment "Variables={FOO=bar}"
```
pass
    def cleanup(self, arn=None):
        pass
    def run_lambda_executor(self, cmd, event=None, func_details=None, env_vars={}):
        process = run(cmd, asynchronous=True, stderr=subprocess.PIPE, outfile=subprocess.PIPE,
                      env_vars=env_vars, stdin=True)
        result, log_output = process.communicate(input=event)
        try:
            result = to_str(result).strip()
        except Exception:
            pass
        log_output = to_str(log_output).strip()
        return_code = process.returncode
        
        
        
        if isinstance(result, six.string_types) and '\n' in result:
            additional_logs, _, result = result.rpartition('\n')
            log_output += '\n%s' % additional_logs
        log_formatted = log_output.strip().replace('\n', '\n> ')
        func_arn = func_details and func_details.arn()
        LOG.debug('Lambda %s result / log output:\n%s\n> %s' % (func_arn, result.strip(), log_formatted))
        
        _store_logs(func_details, log_output)
        if return_code != 0:
            raise Exception('Lambda process returned error status code: %s. Result: %s. Output:\n%s' %
                (return_code, result, log_output))
        return result
class ContainerInfo: