Docker Cookbook

9.3 Listening to Docker Events on Your Docker Hosts
Problem
You want to monitor Docker events on your host. You are interested in image untag‐
ging and deletion and container life-cycle events (e.g., create, destroy, kill).
9.3 Listening to Docker Events on Your Docker Hosts | 277

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Solution
Use the 
docker events
command. It will return a stream of events as they happen on
your Docker host. The command takes a few optional arguments if you want to select
events for a specific time range:
$ docker events --help
Usage: docker events [OPTIONS]
Get real time events from the server
-f, --filter=[] Provide filter values (i.e., 'event=stop')
--help=false Print usage
--since="" Show all events created since timestamp
--until="" Stream events until this timestamp
Although 
docker events
will work and block until you Ctrl-C the stream, you can
use the 
--since
or 
--until
options like so:
$ docker events --since 1427890602
2015-04-01T12:17:04....9393146cb55e5bc9f04e20eb5a0622b3e26aae7: untag
2015-04-01T12:17:09....d5266f8777bfba4974ac56e3270e7760f6f0a81: untag
2015-04-01T12:17:22....d5266f8777bfba4974ac56e3270e7760f6f0a85: untag
2015-04-01T12:17:23....66f8777bfba4974ac56e3270e7760f6f0a81253: delete
2015-04-01T12:17:23....e9b5a793523481a0a18645fc77ad53c4eadsfa2: delete
2015-04-01T12:17:23....878585defcc1bc6f79d2728a13957871b345345: delete
Just as a reminder, you can get the current timestamp in Epoch
with 
date +"%s"
.
Discussion
This 
events
command is also available as an API call, and you can use 
curl
to access
it (see 
Recipe 9.2
). Let’s leave this as an exercise and give an example of using 
docker-
py
to get the list of events.
Recipe 9.2
reconfigured the Docker daemon to access the remote API over TCP. You
can also use 
docker-py
to access the Unix Docker socket. A sample Python script that
would do this and save you some time to reconfigure the Docker daemon looks like
this:
#!/usr/bin/env python