#!/usr/bin/env python3
-# © Copyright 2021-2022, Scott Gasch
+# © Copyright 2021-2023, Scott Gasch
"""Global program configuration driven by commandline arguments and,
optionally, from saved (local or Zookeeper) configuration files... with
optional support for dynamic arguments (i.e. that can change during runtime).
Let's start with an example of how to use :py:mod:`pyutils.config`. It's
-pretty easy for normal commandline arguments because it uses :py:mod:`argparse`:
+pretty easy for normal commandline arguments because it wraps :py:mod:`argparse`
+(see https://docs.python.org/3/library/argparse.html):
In your file.py::
class OptionalRawFormatter(argparse.HelpFormatter):
- """This formatter has the same bahavior as the normal argparse text
- formatter except when the help text of an argument begins with
- "RAW|". In that case, the line breaks are preserved and the text
- is not wrapped.
+ """This formatter has the same bahavior as the normal argparse
+ text formatter except when the help text of an argument begins
+ with "RAW|". In that case, the line breaks are preserved and the
+ text is not wrapped. It is enabled automatically if you use
+ :py:mod:`pyutils.config`.
- Use this, for example, when you need the helptext of an argument
- to have its spacing preserved exactly, e.g.::
+ Use this by prepending "RAW|" in your help message to disable
+ word wrapping and indicate that the help message is already
+ formatted and should be preserved. Here's an example usage::
args.add_argument(
'--mode',
PRECOMPUTE = populate hash table with optimal guesses.
''',
)
+
"""
def _split_lines(self, text, width):
- if text.startswith('RAW|'):
+ if text.startswith("RAW|"):
return text[4:].splitlines()
return argparse.HelpFormatter._split_lines(self, text, width)
description=None,
formatter_class=OptionalRawFormatter,
fromfile_prefix_chars="@",
- epilog=f'{PROGRAM_NAME} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.',
+ epilog=f"{PROGRAM_NAME} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.",
# I don't fully understand why but when loaded by sphinx sometimes
# the same module is loaded many times causing any arguments it
# registers via module-level code to be redefined. Work around
# this iff the program is 'sphinx-build'
- conflict_handler='resolve' if PROGRAM_NAME == 'sphinx-build' else 'error',
+ conflict_handler="resolve" if PROGRAM_NAME == "sphinx-build" else "error",
)
# Arguments specific to config.py. Other users should get their own group by
# invoking config.add_commandline_args.
GROUP = ARGS.add_argument_group(
- f'Global Config ({__file__})',
- 'Args that control the global config itself; how meta!',
+ f"Global Config ({__file__})",
+ "Args that control the global config itself; how meta!",
)
GROUP.add_argument(
- '--config_loadfile',
- metavar='FILENAME',
+ "--config_loadfile",
+ metavar="FILENAME",
default=None,
help='Config file (populated via --config_savefile) from which to read args in lieu or in addition to those passed via the commandline. Note that if the given path begins with "zk:" then it is interpreted as a zookeeper path instead of as a filesystem path. When loading config from zookeeper, any argument with the string "dynamic" in the name (e.g. --module_dynamic_url) may be modified at runtime by changes made to zookeeper (using --config_savefile=zk:path). You should therefore either write your code to handle dynamic argument changes or avoid naming arguments "dynamic" if you use zookeeper configuration paths.',
)
GROUP.add_argument(
- '--config_dump',
+ "--config_dump",
default=False,
- action='store_true',
- help='Display the global configuration (possibly derived from multiple sources) on STDERR at program startup time.',
+ action="store_true",
+ help="Display the global configuration (possibly derived from multiple sources) on STDERR at program startup time.",
)
GROUP.add_argument(
- '--config_savefile',
+ "--config_savefile",
type=str,
- metavar='FILENAME',
+ metavar="FILENAME",
default=None,
help='Populate a config file (compatible with --config_loadfile) and write it at the given path for later [re]use. If the given path begins with "zk:" it is interpreted as a zookeeper path instead of a local filesystem path. When updating zookeeper-based configs, all running programs that read their configuration from zookeeper (via --config_loadfile=zk:<path>) will see the update. Those that also enabled --config_allow_dynamic_updates will change the value of any flags with the string "dynamic" in their names (e.g. --my_dynamic_flag or --dynamic_database_connect_string).',
)
GROUP.add_argument(
- '--config_allow_dynamic_updates',
+ "--config_allow_dynamic_updates",
default=False,
+ action="store_true",
help='If enabled, allow config flags with the string "dynamic" in their names to change at runtime when a new Zookeeper based configuration is created. See the --config_savefile help message for more information about this option.',
)
GROUP.add_argument(
- '--config_rejects_unrecognized_arguments',
+ "--config_rejects_unrecognized_arguments",
default=False,
- action='store_true',
- help='If present, config will raise an exception if it doesn\'t recognize an argument. The default behavior is to ignore unknown arguments so as to allow interoperability with programs that want to use their own argparse calls to parse their own, separate commandline args.',
+ action="store_true",
+ help="If present, config will raise an exception if it doesn't recognize an argument. The default behavior is to ignore unknown arguments so as to allow interoperability with programs that want to use their own argparse calls to parse their own, separate commandline args.",
)
GROUP.add_argument(
- '--config_exit_after_parse',
+ "--config_exit_after_parse",
default=False,
- action='store_true',
- help='If present, halt the program after parsing config. Useful, for example, to write a --config_savefile and then terminate.',
+ action="store_true",
+ help="If present, halt the program after parsing config. Useful, for example, to write a --config_savefile and then terminate.",
)
# Per known zk file, what is the max version we have seen?
self.max_version: Dict[str, int] = {}
+ # The argv after parsing known args.
+ self.parsed_argv: Optional[List[str]] = None
+
def __getitem__(self, key: str) -> Optional[Any]:
"""If someone uses []'s on us, pass it onto self.config."""
return self.config.get(key, None)
return False
@staticmethod
- def print_usage() -> None:
- """Prints the normal help usage message out."""
- ARGS.print_help()
+ def usage() -> str:
+ """
+ Returns:
+ full program usage help text as a string.
+ """
+ return ARGS.format_help()
@staticmethod
- def usage() -> str:
+ def short_usage() -> str:
"""
Returns:
- program usage help text as a string.
+ program short usage text as a string.
"""
return ARGS.format_usage()
+ @staticmethod
+ def print_usage() -> None:
+ """Prints the full help usage message out."""
+ print(config.usage())
+
+ @staticmethod
+ def print_short_usage() -> None:
+ """Prints a short usage/help message."""
+ print(config.short_usage())
+
@staticmethod
def _reorder_arg_action_groups_before_help(entry_module: Optional[str]):
"""Internal. Used to reorder the arguments before dumping out a
Otherwise False is returned.
+ Raises:
+ Exception: On error reading from zookeeper
+
>>> to_bool('True')
True
>>> to_bool('on')
True
"""
- return in_str.lower() in ("true", "1", "yes", "y", "t", "on")
+ return in_str.lower() in {"true", "1", "yes", "y", "t", "on"}
- def _process_dynamic_args(self, event):
+ def _process_dynamic_args(self, event) -> None:
"""Invoked as a callback when a zk-based config changed."""
if not self.zk:
logger = logging.getLogger(__name__)
try:
contents, meta = self.zk.get(event.path, watch=self._process_dynamic_args)
- logger.debug('Update for %s at version=%d.', event.path, meta.version)
+ logger.debug("Update for %s at version=%d.", event.path, meta.version)
logger.debug(
- 'Max known version for %s is %d.',
+ "Max known version for %s is %d.",
event.path,
self.max_version.get(event.path, 0),
)
except Exception as e:
- raise Exception('Error reading data from zookeeper') from e
+ raise Exception("Error reading data from zookeeper") from e
# Make sure we process changes in order.
if meta.version > self.max_version.get(event.path, 0):
# 'dynamic' if we are going to allow them to change at
# runtime as a signal that the programmer is expecting
# this.
- if 'dynamic' in arg and config.config['config_allow_dynamic_updates']:
+ if "dynamic" in arg and config.config["config_allow_dynamic_updates"]:
temp_argv.append(arg)
logger.info("Updating %s from zookeeper async config change.", arg)
- if len(temp_argv) > 0:
+ if temp_argv:
old_argv = sys.argv
sys.argv = temp_argv
known, _ = ARGS.parse_known_args()
def _read_config_from_zookeeper(self, zkpath: str) -> Optional[str]:
from pyutils import zookeeper
- if not zkpath.startswith('/config/'):
- zkpath = '/config/' + zkpath
- zkpath = re.sub(r'//+', '/', zkpath)
+ if not zkpath.startswith("/config/"):
+ zkpath = "/config/" + zkpath
+ zkpath = re.sub(r"//+", "/", zkpath)
try:
if self.zk is None:
contents, meta = self.zk.get(zkpath, watch=self._process_dynamic_args)
contents = contents.decode()
self.saved_messages.append(
- f'Setting {zkpath}\'s max_version to {meta.version}'
+ f"Setting {zkpath}'s max_version to {meta.version}"
)
self.max_version[zkpath] = meta.version
- self.saved_messages.append(f'Read config from zookeeper {zkpath}.')
+ self.saved_messages.append(f"Read config from zookeeper {zkpath}.")
return contents
except Exception as e:
self.saved_messages.append(
- f'Failed to read {zkpath} from zookeeper: exception {e}'
+ f"Failed to read {zkpath} from zookeeper: exception {e}"
)
return None
def _read_config_from_disk(self, filepath: str) -> Optional[str]:
if not os.path.exists(filepath):
return None
- with open(filepath, 'r') as rf:
- self.saved_messages.append(f'Read config from disk file {filepath}')
+ with open(filepath, "r") as rf:
+ self.saved_messages.append(f"Read config from disk file {filepath}")
return rf.read()
def _augment_sys_argv_from_loadfile(self):
saw_other_args = False
grab_next_arg = False
for arg in sys.argv[1:]:
- if 'config_loadfile' in arg:
- pieces = arg.split('=')
+ if "config_loadfile" in arg:
+ pieces = arg.split("=")
if len(pieces) > 1:
loadfile = pieces[1]
else:
else:
saw_other_args = True
- if not loadfile or len(loadfile) == 0:
+ if not loadfile:
return
# Get contents from wherever.
contents = None
- if loadfile[:3] == 'zk:':
+ if loadfile[:3] == "zk:":
contents = self._read_config_from_zookeeper(loadfile[3:])
else:
contents = self._read_config_from_disk(loadfile)
if contents:
if saw_other_args:
- msg = f'Augmenting commandline arguments with those from {loadfile}.'
+ msg = f"Augmenting commandline arguments with those from {loadfile}."
else:
- msg = f'Reading commandline arguments from {loadfile}.'
+ msg = f"Reading commandline arguments from {loadfile}."
print(msg, file=sys.stderr)
self.saved_messages.append(msg)
else:
- msg = f'Failed to read/parse contents from {loadfile}'
+ msg = f"Failed to read/parse contents from {loadfile}"
print(msg, file=sys.stderr)
self.saved_messages.append(msg)
return
# Augment args with new ones.
newargs = [
- arg.strip('\n')
- for arg in contents.split('\n')
- if 'config_savefile' not in arg
+ arg.strip("\n")
+ for arg in contents.split("\n")
+ if "config_savefile" not in arg
]
sys.argv += newargs
print()
def _write_config_to_disk(self, data: str, filepath: str) -> None:
- with open(filepath, 'w') as wf:
+ with open(filepath, "w") as wf:
wf.write(data)
def _write_config_to_zookeeper(self, data: str, zkpath: str) -> None:
- if not zkpath.startswith('/config/'):
- zkpath = '/config/' + zkpath
- zkpath = re.sub(r'//+', '/', zkpath)
+ if not zkpath.startswith("/config/"):
+ zkpath = "/config/" + zkpath
+ zkpath = re.sub(r"//+", "/", zkpath)
try:
if not self.zk:
from pyutils import zookeeper
encoded_data = data.encode()
if len(encoded_data) > 1024 * 1024:
raise Exception(
- f'Saved args are too large ({len(encoded_data)} bytes exceeds zk limit)'
+ f"Saved args are too large ({len(encoded_data)} bytes exceeds zk limit)"
)
if not self.zk.exists(zkpath):
self.zk.create(zkpath, encoded_data)
self.saved_messages.append(
- f'Just created {zkpath}; setting its max_version to 0'
+ f"Just created {zkpath}; setting its max_version to 0"
)
self.max_version[zkpath] = 0
else:
meta = self.zk.set(zkpath, encoded_data)
self.saved_messages.append(
- f'Setting {zkpath}\'s max_version to {meta.version}'
+ f"Setting {zkpath}'s max_version to {meta.version}"
)
self.max_version[zkpath] = meta.version
except Exception as e:
- raise Exception(f'Failed to create zookeeper path {zkpath}') from e
- self.saved_messages.append(f'Saved config to zookeeper in {zkpath}')
+ raise Exception(f"Failed to create zookeeper path {zkpath}") from e
+ self.saved_messages.append(f"Saved config to zookeeper in {zkpath}")
def parse(self, entry_module: Optional[str]) -> Dict[str, Any]:
"""Main program should invoke this early in main(). Note that the
A dict containing the parsed program configuration. Note that this can
be safely ignored since it is also saved in `config.config` and may
be used directly using that identifier.
+
+ Raises:
+ Exception: if unrecognized config argument(s) are detected and the
+ --config_rejects_unrecognized_arguments argument is enabled.
"""
if self.config_parse_called:
return self.config
# when the user passes -h or --help, it will be visible on the
# screen w/o scrolling. This just makes for a nicer --help screen.
for arg in sys.argv:
- if arg in ('--help', '-h'):
+ if arg in {"--help", "-h"}:
if entry_module is not None:
entry_module = os.path.basename(entry_module)
ARGS._action_groups = Config._reorder_arg_action_groups_before_help(
# didn't recognize it, maybe someone else will. Or, if
# --config_rejects_unrecognized_arguments was passed, die
# if we have unknown arguments.
- if len(unknown) > 0:
- if config['config_rejects_unrecognized_arguments']:
+ if unknown:
+ if config["config_rejects_unrecognized_arguments"]:
raise Exception(
- f'Encountered unrecognized config argument(s) {unknown} with --config_rejects_unrecognized_arguments enabled; halting.'
+ f"Encountered unrecognized config argument(s) {unknown} with --config_rejects_unrecognized_arguments enabled; halting."
)
self.saved_messages.append(
- f'Config encountered unrecognized commandline arguments: {unknown}'
+ f"Config encountered unrecognized commandline arguments: {unknown}"
)
sys.argv = sys.argv[:1] + unknown
+ self.parsed_argv = sys.argv[:1] + unknown
# Check for savefile and populate it if requested.
- savefile = config['config_savefile']
- if savefile and len(savefile) > 0:
- data = '\n'.join(ORIG_ARGV[1:])
- if savefile[:3] == 'zk:':
+ savefile = config["config_savefile"]
+ if savefile:
+ data = "\n".join(ORIG_ARGV[1:])
+ if savefile[:3] == "zk:":
self._write_config_to_zookeeper(savefile[3:], data)
else:
self._write_config_to_disk(savefile, data)
# Also dump the config on stderr if requested.
- if config['config_dump']:
+ if config["config_dump"]:
self.dump_config()
# Finally, maybe exit now if the user passed
# --config_exit_after_parse indicating they want to just
# update a config file and halt.
self.config_parse_called = True
- if config['config_exit_after_parse']:
+ if config["config_exit_after_parse"]:
print("Exiting because of --config_exit_after_parse.")
if self.zk:
self.zk.stop()
def late_logging(self):
"""Log messages saved earlier now that logging has been initialized."""
logger = logging.getLogger(__name__)
- logger.debug('Original commandline was: %s', ORIG_ARGV)
+ logger.debug("Invocation commandline: %s", ORIG_ARGV)
for _ in self.saved_messages:
logger.debug(_)
return CONFIG.parse(entry_module)
+def error(message: str, exit_code: int = 1) -> None:
+ """
+ Convenience method for indicating a configuration error.
+ """
+ logging.error(message)
+ print(message, file=sys.stderr)
+ sys.exit(exit_code)
+
+
def has_been_parsed() -> bool:
"""Returns True iff the global config has already been parsed"""
return CONFIG.has_been_parsed()
CONFIG.dump_config()
+def argv_after_parse() -> Optional[List[str]]:
+ """Return the argv with all known arguments removed."""
+ if CONFIG.has_been_parsed():
+ return CONFIG.parsed_argv
+ return None
+
+
def overwrite_argparse_epilog(msg: str) -> None:
"""Allows your code to override the default epilog created by
argparse.
Config.print_usage()
+def print_short_usage() -> None:
+ Config.print_short_usage()
+
+
def usage() -> str:
"""
Returns:
program usage help text as a string.
"""
return Config.usage()
+
+
+def short_usage() -> str:
+ """
+ Returns:
+ program short usage help text as a string.
+ """
+ return Config.short_usage()
projects / pyutils.git / blobdiff