Clean up unused blocks in your nio projects

unused_blocks.py

# Usage:
# From your nio project directory:
# >>> python unused_blocks.py
#
# Or, to delete the unused blocks:
# >>> python unused_blocks.py --delete
import json
import os
from os.path import join
import sys

blocks = {}

for _, _, filenames in os.walk('etc/blocks'):
    for filename in filenames:
        if not filename.endswith('.cfg'):
            continue
        filename = join('etc', 'blocks', filename)
        with open(filename) as block:
            block_cfg = json.load(block)
            block_cfg['__filename'] = filename
            blocks[block_cfg['id']] = block_cfg

for _, _, filenames in os.walk('etc/services'):
    for filename in filenames:
        if not filename.endswith('.cfg'):
            continue
        with open(join('etc', 'services', filename)) as service:
            service_cfg = json.load(service)

        for execution in service_cfg['execution']:
            block_id = execution.get('id', None)
            if block_id in blocks:
                del blocks[block_id]
            for receivers in execution.get('receivers', {}).values():
                for receiver in receivers:
                    if receiver['id'] in blocks:
                        del blocks[receiver['id']]

        for mapping in service_cfg['mappings']:
            block_id = mapping.get('mapping', None)
            if block_id in blocks:
                del blocks[block_id]

if '--delete' in sys.argv:
    for block_cfg in blocks.values():
        print("Deleting {}".format(block_cfg['name']))
        os.remove(block_cfg['__filename'])
else:
    if len(blocks) == 0:
        print("Nice job! No unused blocks! How tidy of you")
        sys.exit(0)
    print("There are {} unused blocks, "
          "pass --delete to remove them:".format(len(blocks)))
    for block_id, block_cfg in blocks.items():
        print(" - {} ({}) ({})".format(
            block_cfg['name'], block_cfg['type'], block_id[:6]))