Chimney is a simple build system primarily intended for web assets. There are many build systems and most asset compilers are capable of watching for changes, but it becomes difficult to manage when more steps are added to the pipeline.
At each step of the process, there is some input, some output and a transformation process. Chimney simply calls these "compilers" for simplicity, but they can be any kind of Python code.
To declare a new type of compiler, define a subclass of
from chimney.compilers import Compiler class coffee(Compiler): def run(self): # perform compile
import chimney chimney.make( coffee('smoke.js', ['wood.coffee', 'fire.coffee']), )
This will compile each of the .coffee dependencies to their .js output
forms using the
coffee compiler defined above, then combine those
Next, there should be a step to minify
smoke.js if needed. That's
easy with chimney, simply add another task to the above definition:
chimney.make( coffee('smoke.js', ['wood.coffee', 'fire.coffee']), uglify('smoke.min.js', 'smoke.js'), )
Chimney already provides compilers for the most popular web assets. Others can easily be added to your script by extending the Compiler class.
Watching for changes
To automatically re-execute tasks when their dependencies change,
chimney.watch will first execute all tasks normally
but then it will watch for any filesystem changes.
To get this functionality, the api is slightly different. Instead of
expecting a list of tasks, the function
a function. This is called when new files are added so the dependencies
can be recalculated. For example:
def create_tasks(): return [ coffee('smoke.js', ['wood.coffee', 'fire.coffee']), uglify('smoke.min.js', 'smoke.js'), ] chimney.watch(create_tasks)
Whenever the coffee files are changed,
smoke.js will be re-created
coffee compiler. Then
smoke.min.js will be created, too.
When new files are added, the function
create_tasks will be re-executed
to build a new set of tasks. This is useful for dynamically building
By default, the reload will start chimney on all new files, which may be too often. You can provide a list of (shell) patterns to match to limit reloading:
def create_tasks(): return [ coffee('smoke.js', ['wood.coffee', 'fire.coffee']), uglify('smoke.min.js', 'smoke.js'), ] chimney.watch(create_tasks, reload_patterns=['*.coffee'])