borgmatic/borgmatic/hooks/command.py

96 lines
3.2 KiB
Python

import logging
import os
import re
from borgmatic import execute
logger = logging.getLogger(__name__)
SOFT_FAIL_EXIT_CODE = 75
def interpolate_context(config_filename, hook_description, command, context):
'''
Given a config filename, a hook description, a single hook command, and a dict of context
names/values, interpolate the values by "{name}" into the command and return the result.
'''
for name, value in context.items():
command = command.replace(f'{{{name}}}', str(value))
for unsupported_variable in re.findall(r'{\w+}', command):
logger.warning(
f"{config_filename}: Variable '{unsupported_variable}' is not supported in {hook_description} hook"
)
return command
def execute_hook(commands, umask, config_filename, description, dry_run, **context):
'''
Given a list of hook commands to execute, a umask to execute with (or None), a config filename,
a hook description, and whether this is a dry run, run the given commands. Or, don't run them
if this is a dry run.
The context contains optional values interpolated by name into the hook commands.
Raise ValueError if the umask cannot be parsed.
Raise subprocesses.CalledProcessError if an error occurs in a hook.
'''
if not commands:
logger.debug(f'{config_filename}: No commands to run for {description} hook')
return
dry_run_label = ' (dry run; not actually running hooks)' if dry_run else ''
context['configuration_filename'] = config_filename
commands = [
interpolate_context(config_filename, description, command, context) for command in commands
]
if len(commands) == 1:
logger.info(f'{config_filename}: Running command for {description} hook{dry_run_label}')
else:
logger.info(
f'{config_filename}: Running {len(commands)} commands for {description} hook{dry_run_label}',
)
if umask:
parsed_umask = int(str(umask), 8)
logger.debug(f'{config_filename}: Set hook umask to {oct(parsed_umask)}')
original_umask = os.umask(parsed_umask)
else:
original_umask = None
try:
for command in commands:
if not dry_run:
execute.execute_command(
[command],
output_log_level=logging.ERROR
if description == 'on-error'
else logging.WARNING,
shell=True,
)
finally:
if original_umask:
os.umask(original_umask)
def considered_soft_failure(config_filename, error):
'''
Given a configuration filename and an exception object, return whether the exception object
represents a subprocess.CalledProcessError with a return code of SOFT_FAIL_EXIT_CODE. If so,
that indicates that the error is a "soft failure", and should not result in an error.
'''
exit_code = getattr(error, 'returncode', None)
if exit_code is None:
return False
if exit_code == SOFT_FAIL_EXIT_CODE:
logger.info(
f'{config_filename}: Command hook exited with soft failure exit code ({SOFT_FAIL_EXIT_CODE}); skipping remaining actions',
)
return True
return False