Custom Options

Custom options (and command line options) can be created with the help of the property() function. It's usable on both services and tasks.

Here's an example

> cat option_example.py 
from sparts.tasks.periodic import PeriodicTask
from sparts.vservice import VService
from sparts.sparts import option
import socket

class HostCheckTask(PeriodicTask):
    INTERVAL = 5
    check_name = option('check-name', default=socket.getfqdn(), type=str,
                        help='Name to check [%(default)s]')

    def execute(self, *args, **kwargs):
        self.logger.info("LOOKUP %s => %s", self.check_name,
                         socket.gethostbyname(self.check_name))

class DNSChecker(VService):
    TASKS=[HostCheckTask]

DNSChecker.initFromCLI()

Running with -h shows:

> python option_example.py -h  
usage: option_example.py [-h] [--tasks [TASK [TASK ...]]] [--level LEVEL]
                         [--dryrun]
                         [--HostCheckTask-check-name HOSTCHECKTASK_CHECK_NAME]
                         [--HostCheckTask-interval SECONDS]

optional arguments:
  -h, --help            show this help message and exit
  --tasks [TASK [TASK ...]]
                        Tasks to run. Pass without args to see the list. If
                        not passed, all tasks will be started
  --level LEVEL         Log Level [DEBUG]
  --dryrun              Run in "dryrun" mode
  --HostCheckTask-check-name HOSTCHECKTASK_CHECK_NAME
                        Name to check [pete-P35C-DS3R]
  --HostCheckTask-interval SECONDS
                        How often this task should run [5] (s)

And running the program:

> python option_example.py  --HostCheckTask-check-name sphotos-a.xx.fbcdn.net
DEBUG:DNSChecker:All tasks started
INFO:DNSChecker.HostCheckTask:LOOKUP sphotos-a.xx.fbcdn.net => 31.13.69.58

Setting overridable defaults

In some cases (like with PeriodicTask) it's convenient to provide options with overridable defaults.

The trick to doing this is currently a kind of a hack; you need to set a callable that explicitly takes the class as the first parameter. This allows something like this to work:

class MyTask(PeriodicTask):
    DEFAULT_PORT = 80
    port = option('port', default=lambda cls: cls.DEFAULT_PORT)

class MyOtherTask(MyTask):
    DEFAULT_PORT = 8080