Running invoke from other folders

While working on big projects, sometimes, you have invoke tasks lying around in different places. It wouldn’t make sense to merge them together but rather help each other out as and when needed.

One such way for this would be to search for invoke tasks from other folders and run them directly when they can be used.

I had to go for this approach for a monolithic repo where multiple projects were being built in mostly similar style with minor modifications. All of them would have the same set of commands along with same style of running those commands. I didn’t want to set up the same invoke task for all individual projects but rather a common set of tasks that could be re-used by each one of them.

Hence, here’s what I did:

1. I knew for a fact that most sub-projects needed the same command to build themselves. I didn’t want to use the same command over and over again in each of the projects. I would rather use the command in the general space and override it only when a sub-project requires a special version of the build command.
2. When the general invoke was called to do any task, it would first check whether, the sub-project for which the command was to run, the command was already available for the given sub-project itself.
   • If yes, this would mean that sub-project intends to override the default command in it’s own style
   • If no, then the default version is to run

Here’s the simplilfied version of the code.

import subproces
import os

@contextmanager
def cd(path):
    old = os.getcwd()
    os.chdir(path)
    try:
        yield
    finally:
        os.chdir(old)


@task
def build():
    folder_to_run_the_command_on = '/home/folder'
    with cd(folder_to_run_the_command_on):
        print('Finding tasks...')
        # List all the possible commands that you can run on that folder
        res = subprocess.check_output(['invoke', '-l'])
        # does it contain this command that we need to run?
        if 'build'  in res:
            print('Found the build command in "{}" folder'.format(folder_to_run_the_command_on)
            run('invoke build')
        else:
            # we need to run the generic version of build command
            build_internal()