Example of alerting system promise type

Files

• alerting_system/test.cf - the policy which uses the alerting system promise type.
• alerting_system/alerting_system.py the module, written in python, uses the cfengine.py python library
• alerting_system/enable.cf policy snippet needed to enable the promise type. This is where you can point it to a different python binary.
• alerting_system/server.py a small python server to test that the module sent HTTP requests.
• cfbs.json CFEngine Build project file, used by cfbs CLI, defines how we build a policy set from multiple modules. Might be interesting to read through even if you are not using it.

The library for creating promise types in Python, cfengine.py, can be found here:

https://build.cfengine.com/modules/library-for-promise-types-in-python/

Build and deploy with tooling

If you are using cfbs and cf-remote, do:

$ cfbs build && cf-remote deploy

(Requires cfbs 2.2.0 or newer).

Adding to a policy set manually

Assuming you are using the Masterfiles Policy Framework(MPF) in /var/cfengine/masterfiles:

$ mkdir -p /var/cfengine/masterfiles/modules/promises/
$ curl https://raw.githubusercontent.com/cfengine/modules/master/libraries/python/cfengine.py > /var/cfengine/masterfiles/modules/promises/cfengine.py
$ cp alerting_system/alerting_system.py /var/cfengine/masterfiles/modules/promises/
$ cat alerting_system/enable.cf >> /var/cfengine/masterfiles/services/init.cf
$ cp test.cf /var/cfengine/masterfiles/services/autorun/

If you are not using autorun, you need to add test.cf to inputs and the bundle test_alerting_system to your bundle sequnce, or enable autorun in /var/cfengine/masterfiles/def.json:

{
  "classes": {
    "services_autorun": ["any"]
  }
}

Links

• Custom promise type specification / documentation - Includes details on how the protocol works and how you could implement it in another language
• CFEngine Build - The website where we have all kinds of modules, including promise types, inventory data and reports, security hardening, etc.
• Custom promise types available on CFEngine Build
• New getting started tutorial series - Part 5 is about developing modules