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# Type of request: This is a ...

[x ] bug report
[ ] feature request

# Detailed description

Not able to use the edge service to write metric data to cloudwatch via the javascript aws-sdk.

However, It **DOES** work when using the deprecated cloudwatch port.

## Expected behavior

Metric data to be visible when calling `awslocal cloudwatch list-metrics`

## Actual behavior

404 from edge service. No metric data is persisted, localstack instance logs the following info:

```
INFO:localstack.services.edge: Unable to determine forwarding port for API "monitoring" - please make sure this API is enabled via the SERVICES configuration
```

# Steps to reproduce

Run JS code in "Client code" section.
See 404 Error

## Command used to start LocalStack

`TMPDIR=/tmp/localstack docker-compose up`

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

```js
const AWS = require('aws-sdk')
const cw = new AWS.CloudWatch({
  endpoint: 'http://localhost:4566',
})

const data = {
  Namespace: 'ns',
  MetricData: [
    {
      MetricName: 'metric-name',
      Timestamp: new Date(),
      Value: 12345,
      Unit: 'Milliseconds',
      Dimensions: [
        { Name: 'Environment', Value: 'local' },
      ]
    }
  ]
}

cw.putMetricData(data, (err, data) => {
  if (err) {
      console.log('Error', err)
  } else {
      console.log('Success', JSON.stringify(data))
  }
})
```

if not is_port_open(port, http_path=http_path, expect_success=expect_success):
            raise Exception()
    return retry(check, sleep=sleep_time, retries=retries)
def get_free_tcp_port(blacklist=None):
    blacklist = blacklist or []
    for i in range(10):
        tcp = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        tcp.bind(('', 0))
        addr, port = tcp.getsockname()
        tcp.close()
        if port not in blacklist:
            return port
    raise Exception('Unable to determine free TCP port with blacklist %s' % blacklist)
def sleep_forever():
    while True:
        time.sleep(1)
def get_service_protocol():
    return 'https' if config.USE_SSL else 'http'
def timestamp(time=None, format=TIMESTAMP_FORMAT):
    if not time:
        time = datetime.utcnow()
    if isinstance(time, six.integer_types + (float, )):
        time = datetime.fromtimestamp(time)
    return time.strftime(format)
def timestamp_millis(time=None):
    microsecond_time = timestamp(time=time, format=TIMESTAMP_FORMAT_MICROS)
    
    return microsecond_time[:-4] + microsecond_time[-1]
def retry(function, retries=3, sleep=1, sleep_before=0, **kwargs):