Skip to content

Latest commit

 

History

History
138 lines (94 loc) · 3.43 KB

README.rst

File metadata and controls

138 lines (94 loc) · 3.43 KB
Raw

There is a lot of boilerplate and copypasta associated with building services (or any other software that runs continuously and does things)

sparts is a python library developed at Facebook that aims to eliminate as much of the skeleton code as possible, making it as dead simple to write new services with little to no excess code.

Design Goals

  • Be able to implement services with as little code as possible
  • Support as many RPC transports as possible (thrift, http, dbus, etc)
  • Make it painless to integrate services that require custom IO loops (twisted, tornado, glib, etc)

HOWTO

A sparts service typically consists of two parts, the core "service", and its "tasks". Background and offline processing is generally done by tasks, while common or shared functionality belongs to the service.

Service

sparts.vtask.VService - This is the core of any sparts service.

Simply subclass VService for any custom service instance logic, and run its initFromCLI() and you are done.

For example, myservice.py:

from sparts.vservice import VService
class MyService(VService):
    pass

MyService.initFromCLI()

Now, you can run this file with the -h option (to see the available options), or run with: python myservice.py

This should emit something like the following output:

DEBUG:VService:All tasks started``

And pressing ^C will emit:

^CINFO:VService:KeyboardInterrupt Received!  Stopping Tasks...
INFO:VService:Instance shut down gracefully

This simple service, by itself, is pretty damn useless. That's where Tasks come into play

Tasks

sparts.vtask.VTask - This is the base class for all tasks

Tasks are what trigger your program to take action. This action can be processing periodic events, handling HTTP requests, handling thrift requests, working on items from a queue, waking up on an event, operating some ioloop, or whatever.

Here's a simple example of a service with tasks (requires tornado installed):

from sparts.vservice import VService
from sparts.tasks.tornado import TornadoHTTPTask
TornadoHTTPTask.register()
VService.initFromCLI()

Now running it emits:

> python myservice.py --http-port 8000
INFO:VService.TornadoHTTPTask:TornadoHTTPTask Server Started on 0.0.0.0 (port 8000)
INFO:VService.TornadoHTTPTask:TornadoHTTPTask Server Started on :: (port 8000)
DEBUG:MyService:All tasks started

And as you can see, you can curl the webserver:

> curl localhost:8000
Hello, world

Tasks can be subclassed to do all kinds of things. This one prints the current unix timestamp every second:

from sparts.tasks.periodic import PeriodicTask

class PrintClock(PeriodicTask):
    INTERVAL = 1.0
    def execute(self):
        print time.time()
PrintClock.register()

from sparts.vservice import VService
VService.initFromCLI()

And the result:

DEBUG:VService:All tasks started
DEBUG:VService:VService Active.  Awaiting graceful shutdown.
1376081805.08
1376081806.08
1376081807.08
1376081808.08
1376081809.08
1376081810.08
1376081811.08

HALP

If you have any questions, comments, feedback, suggestions, etc, please feel free to contact me at any time.

License

sparts is BSD-licensed. We also provide an additional patent grant.