pyconfd is like confd but written in python. Instead of plaintext configuration files, use python to write a tiny bit of code to query anything, which is then used to render a jinja2 template.

installation

pip install pyconfd

setup

# store python plugins here
mkdir -p /etc/pyconfd/conf.d/

# store jinja templates here
mkdir -p /etc/pyconfd/templates/

Also, make sure that pyconfd is launched.

usage

Launch pyconfd directly:

pyconfd

At the moment, there is no daemon mode. Users of supervisord can write a supervisor config file like:

[program:pyconfd]
command=pyconfd
numprocs=1
numprocs_start=0
priority=30
autostart=true
autorestart=unexpected
startsecs=30
startretries=10
exitcodes=0,2
stopsignal=TERM
stopwaitsecs=10
directory=/
user=root
redirect_stderr=false
stdout_logfile=/data/log/supervisor/pyconfd.out
stdout_logfile_maxbytes=1MB
stdout_logfile_backups=10
stderr_logfile=/data/log/supervisor/pyconfd.err
stderr_logfile_maxbytes=1MB
stderr_logfile_backups=10

plugin example

Check out the examples. Basically put this in in a .py file in /etc/pyconfd/conf.d/ and write something like:

import pyconfd
import random

class BashPlugin(pyconfd.Plugin):
    # filename of template from /etc/pyconf.d/templates/
    src = "bash.cfg.tmpl"

    # where to dump the generated config file
    dest = "/tmp/bash.cfg"

    # force reload of daemon, consider using supervisordctl
    reload_cmd = "bash -c 'exit'"

    def get(self):
        return {"number": random.randrange(1, 101)}

And the jinja template bash.cfg.tmpl can look like:

echo "The number is: {{ number }}"

real-world plugins

The plugin's "get" method can be written to do whatever. I often use it with consul like with consulate or pyconsul. Others may prefer to query etcd.

consulate

Extract a list of servers running a certain service, and their IP addresses.

import pyconfd
import consulate

class HAProxy(pyconfd.Plugin):
    def get(self):
        """
        Get relevant variables from consul.

        :rtype: dict
        """
        data = {"servers": {}}
        session = consulate.Consulate()
        services = session.catalog.services().keys()
        for service in services:
            data["servers"][service] = []
            servers = session.catalog.service(service)
            for server in servers:
                ip_address = server["Address"]
                data["servers"][service].append(ip_address)
        return data

future work

• daemon mode
• tests
• Switch away from gevent.sleep and use consul hooks to trigger config updates. This will deprecate most of this library.

license

BSD