Echo-ing StatsD metrics locally

It's useful to know what StatsD metrics you're sending locally before it hits your production metrics sink. Getting a metric name, namespace, or data type incorrect in production is annoying, and it can mess up metrics for a certain time window after it's fixed.

Assuming this example that sends a metric:

1from time import sleep
2import statsd
3
4c = statsd.StatsClient("localhost", 8125)
5
6while True:
7    sleep(2)
8    c.timing("stats.timed", 1)
9    c.incr("foo")

You can follow what it's sending locally by using netcat to listen for the UDP packets:

1$ nc -ulv -p 8125
2Received packet from 127.0.0.1:58916 -> 127.0.0.1:8125 (local)
3stats.timed:1.000000|msfoo:1|c

$ nc -ulv starts nc in UDP listening mode:

• -u = UDP
• -l = Listen
• -v = Verbose Logs
• -p = Port of your StatsD emitter