MmStats: Delicious Data

Documentation | Package | Code

About

Mmstats is a way to expose and read diagnostic values and metrics for applications.

Think of mmstats as /proc for your application and the readers as procps utilities.

This project is a Python implementation, but compatible implementations can be made in any language (see Goals).

Discuss at https://groups.google.com/group/python-introspection

Goals

• Separate publishing/writing from consuming/reading tools
• Platform/language independent (a Java writer can be read by a Python tool)
• Predictable performance impact for writers via:
  • No locks (1 writer per thread)
  • No syscalls (after instantiation)
  • All in userspace
  • Reading has no impact on writers
• Optional persistent (writer can sync anytime)
• 1-way (Publish/consume only; mmstats are not management extensions)

Usage

Requirements

CPython 2.6 or 2.7 (Windows is untested)

PyPy (only tested in 1.7, should be faster in 1.8)

Using

1. python setup.py install
2. import mmstats
3. Create a subclass of mmstats.MmStats like:

class WebStats(mmstats.MmStats):
    status2xx = mmstats.CounterField(label='status.2XX')
    status3xx = mmstats.CounterField(label='status.3XX')
    status4xx = mmstats.CounterField(label='status.4XX')
    status5xx = mmstats.CounterField(label='status.5XX')
    last_hit = mmstats.DoubleField(label='timers.last_hit')

4. Instantiate it once per thread/process:

webstats = WebStats(label_prefix='web.stats.')

5. Record some data:

if response.status_code == 200:
    webstats.status2xx.inc()

webstats.last_hit = time.time()

6. Run slurpstats to read it
7. Run mmash to create a web interface for stats
8. Run pollstats -p web.stats.status 2XX,3XX,4XX,5XX /tmp/mmstats-* for a vmstat/dstat like view.
9. Did a process die unexpectedly and leave around a stale mmstat file? cleanstats /path/to/mmstat/files will check to see which files are stale and remove them.

Development

It’s easiest to develop mmstats within a virtualenv:

$ git clone git://github.com/schmichael/mmstats.git
$ cd mmstats
$ virtualenv .
$ source bin/activate
$ python setup.py develop
$ ./run_flask_example # This starts up a sample web app
$ curl http://localhost:5001/
$ curl http://localhost:5001/500
$ curl http://localhost:5001/status
$ # If you have ab installed:
$ ab -n 50 -c 10 http://localhost:5001/

Now to view the stats run the following in a new terminal:

$ # To get a raw view of the data:
$ slurpstats mmstats-*
$ # Or start up the web interface:
$ mmash
$ # Run pollstats while ab is running:
$ pollstats -p flask.example. ok,bad,working mmstats-*

To cleanup stray mmstats files: rm mmstats-flask-*

The web interface will automatically reload when you change source files.

Put static files into static/ and template files into templates/

TODO: Factor mmash out into it’s own project (with a meaningful name?)

Testing

Feel free to use your favorite test runner like nose or pytest or just run:

$ python setup.py test

Further topics

• Development
• History
• Contributors

API Reference

• API
  • Models
  • Model Fields
  • Reader API
  • Internal Defaults
  • mmap Compatibility Wrapper

Indices and tables

• Index
• Module Index
• Search Page