Support user defined processes

User defined processes are defined by new cdist beta command 'process'.

Processes can be defined in `process` subdirectory in `$HOME/.cdist` or
in custom directories specified through CDIST_PROCESS_PATH environment
variable.

`<path>/process` processes are defined in subdirectories, where a
directory must contain `__init__.py` file to be recognized as a process,
and it is then imported as a module.

Since scanning and registering processes happens before cdist arguments
are parsed, then standard cdist logging cannot be used in this stage.
This is why CDIST_PROCESS_DEBUG environemnt variable turns on debug
messages.

Dummy example (`~/.cdist/process/homeprocess/__init__.py`):

    #!/usr/bin/env python3
    # -*- coding: utf-8 -*-

    import logging
    import subprocess

    log = logging.getLogger(__name__)

    def register(parent_parser):
        parser = parent_parser.add_parser('cdist-help')
        parser.set_defaults(func=cdist_help)

    def cdist_help(args):
        cmd = [ "cdist", "-h", ]
        log.info("Running my process cdist help")
        subprocess.check_call(cmd)
This commit is contained in:
Darko Poljak 2020-01-11 11:29:32 +01:00
parent 3258fc98e1
commit d17f75a010
2 changed files with 91 additions and 1 deletions

View file

@ -7,10 +7,11 @@ import functools
import cdist.configuration import cdist.configuration
import cdist.preos import cdist.preos
import cdist.info import cdist.info
import cdist.process
# set of beta sub-commands # set of beta sub-commands
BETA_COMMANDS = set(('install', 'inventory', )) BETA_COMMANDS = set(('install', 'inventory', 'process', ))
# set of beta arguments for sub-commands # set of beta arguments for sub-commands
BETA_ARGS = { BETA_ARGS = {
'config': set(('tag', 'all_tagged_hosts', 'use_archiving', )), 'config': set(('tag', 'all_tagged_hosts', 'use_archiving', )),
@ -468,6 +469,14 @@ def get_parsers():
'pattern', nargs='?', help='Glob pattern.') 'pattern', nargs='?', help='Glob pattern.')
parser['info'].set_defaults(func=cdist.info.Info.commandline) parser['info'].set_defaults(func=cdist.info.Info.commandline)
# Process
parser['process'] = parser['sub'].add_parser(
'process', parents=[parser['loglevel'], parser['beta'], ])
parser['process_sub'] = parser['process'].add_subparsers(title="Processes")
parser['process'].set_defaults(func=functools.partial(
cdist.process.commandline, parser=parser['process']))
cdist.process.setup(parser['process_sub'])
for p in parser: for p in parser:
parser[p].epilog = EPILOG parser[p].epilog = EPILOG

81
cdist/process.py Normal file
View file

@ -0,0 +1,81 @@
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# 2020 Darko Poljak (darko.poljak at gmail.com)
#
# This file is part of cdist.
#
# cdist is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cdist is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with cdist. If not, see <http://www.gnu.org/licenses/>.
#
#
import os
import sys
import importlib
import re
import cdist
PROCESS_PARENT = 'process'
_PROCESS_DEBUG = os.environ.get('CDIST_PROCESS_DEBUG', None)
if _PROCESS_DEBUG:
def _debug(msg):
print('[cdist process debug] {}'.format(msg))
else:
def _debug(msg):
pass
_process_path = []
_env_path = os.environ.get('CDIST_PROCESS_PATH', None)
if _env_path:
for x in re.split(r'(?<!\\):', _env_path):
if x:
_debug('Adding CDIST_PROCESS_PATH {}'.format(x))
_process_path.append(x)
_home_dir = cdist.home_dir()
if _home_dir:
_debug('Adding cdist home dir process path {}'.format(_home_dir))
_process_path.append(_home_dir)
def _scan_processes():
for path in _process_path:
process_path = os.path.join(path, PROCESS_PARENT)
for fname in os.listdir(process_path):
entry = os.path.join(process_path, fname)
if not os.path.isdir(entry):
continue
_debug('Scanning {}'.format(entry))
pfile = os.path.join(entry, '__init__.py')
_debug('Scanning {}'.format(pfile))
if os.path.exists(pfile):
_debug('Found process in {}: {}'.format(entry, pfile))
yield entry
def setup(parent_parser):
for entry in _scan_processes():
mod_name = os.path.basename(entry)
mod_dir = os.path.dirname(entry)
sys.path.insert(0, mod_dir)
proc_mod = importlib.import_module(mod_name)
_debug('Registering process module {} from {}'.format(
mod_name, entry))
proc_mod.register(parent_parser)
def commandline(args, parser):
parser.print_help()