Taskwarrior hook script that adds a "blocks:" pseudo-attribute for adding/modifying tasks.

on-modify.blocks_attr.py

#!/usr/bin/env python
#
# Adds the ability to add / modify tasks using a "blocks:" attribute,
# the opposite of "depends:".
#
# This script acts as an on-modify, on-add and on-launch hook at the same time.
#
### SETUP
# Save this file as
#   ~/.task/hooks/on-modify.blocks_attr.py
# change to that directory:
#   $ cd ~/.task/hooks
# make the script executable:
#   $ chmod +x on-modify.blocks_attr.py
# then create symlinks to that file with the other hook names:
#   $ ln -s on-modify.blocks_attr.py on-add.blocks_attr.py
#   $ ln -s on-modify.blocks_attr.py on-launch.blocks_attr.py
#
# Now tell Taskwarrior about the "blocks" attribute:
#   $ task config uda.blocks.type string
#   $ task config uda.blocks.label Blocks
#
# And we're ready to go!
#
# bf@id:~$ t add a
# Created task 1.
#
# bf@id:~$ t add b
# Created task 2.
#
# bf@id:~$ t add c blocks:1
# Created task 3.
#
# bf@id:~$ t 2 mod blocks:1
# Modifying task 2 'b'.
# Modified 1 task.
#
# bf@id:~$ t
# [t next]
#
# ID Age Deps Description Urg 
#  2 18s      b              8
#  3 8s       c              8
#  1 29s 2 3  a             -5
#

import json
import os
import subprocess
import sys

# Adjust this if "task" is not regular Taskwarrior.
TASK = 'task'
# Adjust path if needed. It is a temporary file managed by the hook.
SHIMFILE = "%s/.task/hooks/blocks_shim.txt" % os.getenv('HOME')

def on_launch():
    try:
        with open(SHIMFILE, 'r') as f:
            shim = f.readlines()
    except IOError:
        sys.exit(0)
    while shim:
        line = shim.pop(0).rstrip()
        if not line:
            continue
        if subprocess.call(line.split()) != 0:
            # Error handling by escalating to the user :)
            print("%s ERROR: First line in %s is failing to run!" % (sys.argv[0], SHIMFILE))
            print("Feel free to delete the file, or edit its contents to resolve the problem.")
            shim = [line + '\n'] + shim
            break
    if shim:
        with open(SHIMFILE, 'w') as f:
            f.write(''.join(shim))
        sys.exit(1)
    else:
        os.remove(SHIMFILE)

def handle_blocks_attribute(new):
    if 'blocks' in new:
        with open(SHIMFILE, "a") as f:
            # This needs error handling. If a later hook aborts, the UUID is invalid.
            f.write("%s rc.hooks=off rc.confirmation=no rc.bulk=10000 rc.verbose=nothing %s mod dep:%s\n" % (TASK, new['blocks'], new['uuid']))
        del new['blocks']
    print(json.dumps(new))

old = sys.stdin.readline()
new = sys.stdin.readline()

if not old:
    on_launch()
elif not new:
    handle_blocks_attribute(json.loads(old))
else:
    handle_blocks_attribute(json.loads(new))

Great script!

I've made one change in my fork: I changed the declaration of SHIMFILE to use the hook file's own location to determine the directory that the shim file should reside in. Please feel free to look at my fork (https://gist.github.com/rjray/f95d0919447afa956a1753d7ccec87b6)... I've tested the hook in my own taskwarrior repo and it works fine.