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# Type of request: This is a ...

[*] bug report
[ ] feature request

# Detailed description

Sending CloudWatch metrics data using `content-encoding: gzip` encoding results in 404. The same metrics sent uncompressed using `content-encoding: identity` returns 200 OK.

The metrics compressed with `content-encoding: gzip` work against AWS CloudWatch.

According to [CloudWatch documentation](https://docs.aws.amazon.com/AmazonCloudWatch/latest/APIReference/API_PutMetricData.html) `PutMetricData` accepts `gzip` compressed payloads but the docs are not clear on content-encoding at that point.

> Each PutMetricData request is limited to 40 KB in size for HTTP POST requests. You can send a payload compressed by gzip. Each request is also limited to no more than 20 different metrics.

## Expected behavior

I expected `localstack` `cloudwatch` to be able to receive `gzip` encoded payloads.

## Actual behavior

`encoding: gzip` results in HTTP error 404.

# Steps to reproduce

The Elixir library `telemetrics_library_cloudwatch` uses `gzip` compression by default. I configured a bunch of metrics and configured the library to periodically send the metrics. This resulted in 404 failures.

The requests against the `localstack` container started working when I commented out the `gzip` content type setting in line 12 of `TelemetryMetricsCloudWatch.Cloudwatch` module [here](https://github.com/bmuller/telemetry_metrics_cloudwatch/blob/2293af20e80c058338c8d4248191518642484986/lib/telemetry_metrics_cloudwatch/cloudwatch.ex#L12)

Apologies for not having simpler steps to reproduce.

## Command used to start LocalStack

Docker Compose with following settings:

```
  localstack:
    image: localstack/localstack:0.12.3
    restart: always
    environment:
      - SERVICES=s3,cloudwatch
      - DEFAULT_REGION=eu-west-2
      - DEBUG=1
      - DATA_DIR=/tmp/localstack/data
      - DOCKER_HOST=unix:///var/run/docker.sock
      - HOST_TMP_FOLDER=/tmp/localstack
    ports:
      - 4566-4599:4566-4599
    volumes:
      - /tmp/localstack:/tmp/localstack
      - /var/run/docker.sock:/var/run/docker.sock
```

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



if port and int(port) < 0:
            return 404
        if not port:
            api, port = get_api_from_custom_rules(method, path, data, headers) or (api, port)
        if not port:
            if method == 'OPTIONS':
                return 200
            if api in ['', None, '_unknown_']:
                truncated = truncate(data)
                LOG.info(('Unable to find forwarding rule for host "%s", path "%s %s", '
                    'target header "%s", auth header "%s", data "%s"') % (
                        host, method, path, target, auth_header, truncated))
            else:
                LOG.info(('Unable to determine forwarding port for API "%s" - please '
                    'make sure this API is enabled via the SERVICES configuration') % api)
            response = Response()
            response.status_code = 404
            response._content = '{"status": "running"}'
            return response
        if api and not headers.get('Authorization'):
            headers['Authorization'] = aws_stack.mock_aws_request_headers(api)['Authorization']
        headers['Host'] = host
        if isinstance(data, dict):
            data = json.dumps(data)
        lock_ctx = BOOTSTRAP_LOCK
        if persistence.API_CALLS_RESTORED or is_internal_call_context(headers):
            lock_ctx = empty_context_manager()
        with lock_ctx:
            return do_forward_request(api, method, path, data, headers, port=port)
    def return_response(self, method, path, data, headers, response, request_handler=None):