Simple script to watch and build your coffeescript files.

build.py

"""
Grunt.js was too complex for me. after adding a third project, 
we ran into some wierd timer.js errors and gave up.  
This python solution is pretty straightforward 
and works well enough.
"""
import subprocess
import sys
import time
from watchdog.observers import Observer
from watchdog.events import PatternMatchingEventHandler

projects = {
    'project1' : {
        'input' : 'project1/static/coffee',
        'output' : 'project1/static/js'
        },
    'project2' : {
        'input' : 'project2/static/coffee',
        'output' : 'project2/static/js'
        },
    'project3' : {
        'input' : 'project3/static/coffee',
        'output' : 'project3/static/js'
        }
    }

def build(inputdir, outputdir):
    command = "coffee --compile --output %s %s"
    command = command %(outputdir, inputdir)
    print command
    proc = subprocess.Popen(command, shell=True,
                            stdout=subprocess.PIPE,
                            stdin=subprocess.PIPE)
    data = proc.communicate()
    print data[0]
    print data[1]

def build_all():
    for project in projects:
        inputs = projects[project]['input']
        outputs = projects[project]['output']
        build(inputs, outputs)

class MyHandler(PatternMatchingEventHandler):
    def __init__(self, inputs, outputs):
        super(MyHandler, self).__init__(
            patterns=["*.coffee"], case_sensitive=True)
        self.inputs = inputs
        self.outputs = outputs
        
    def on_any_event(self, event):
        print event
        build(self.inputs, self.outputs)

if __name__ == "__main__":
    """
    usage:
    python build.py build -builds all projects once
    python build.py watch - builds all projects once, then watches for changes.
    """
    if len(sys.argv) >= 2 and  sys.argv[1] == "build":
        build_all()
    else:
        build_all()        
        observer = Observer()        
        for project in projects:
            inputs = projects[project]['input']
            outputs = projects[project]['output']
            event_handler = MyHandler(inputs, outputs)
            print inputs
            observer.schedule(event_handler, path=inputs, recursive=True)
        observer.start()            
        try:
            while True:
                time.sleep(1)
        except KeyboardInterrupt:
            observer.stop()
        observer.join()