# 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}"
```
return re.sub(r'^%s/(.*)$' % config.TMP_FOLDER,
                      r'%s/\1' % config.HOST_TMP_FOLDER, path)
    @classmethod
    def format_windows_path(cls, path):
        temp = path.replace(':', '').replace('\\', '/')
        if len(temp) >= 1 and temp[:1] != '/':
            temp = '/' + temp
        temp = '%s%s' % (config.WINDOWS_DOCKER_MOUNT_PREFIX, temp)
        return temp
    @classmethod
    def docker_image_for_runtime(cls, runtime):
        docker_tag = runtime
        docker_image = config.LAMBDA_CONTAINER_REGISTRY
        
        
        lambdas_to_add_prefix = ['dotnetcore2.0', 'dotnetcore2.1', 'python2.7', 'python3.6', 'python3.7']
        if docker_image == 'lambci/lambda' and any(img in docker_tag for img in lambdas_to_add_prefix):
            docker_tag = '20191117-%s' % docker_tag
        return '"%s:%s"' % (docker_image, docker_tag)
    @classmethod
    def get_docker_remove_flag(cls):
        return '--rm' if config.LAMBDA_REMOVE_CONTAINERS else ''
    @classmethod
    def get_java_classpath(cls, archive):
        """
        Return the Java classpath, using the parent folder of the