X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;f=config.py;h=1ac5cff30add3fcbd0eb0a03d7361f06515cbbfe;hb=e8fbbb7306430478dec55d2c963eed116d8330cc;hp=dccfc27d5e9e64fa1bc83bfc3b4e825f89949fe4;hpb=97fbe845e5dfdbda22521117c1783e1fd8515952;p=python_utils.git diff --git a/config.py b/config.py index dccfc27..1ac5cff 100644 --- a/config.py +++ b/config.py @@ -1,7 +1,9 @@ #!/usr/bin/env python3 -"""Global configuration driven by commandline arguments (even across -different modules). Usage: +"""Global configuration driven by commandline arguments, environment variables +and saved configuration files. This works across several modules. + +Usage: module.py: ---------- @@ -36,7 +38,8 @@ different modules). Usage: config.parse() # Very important, this must be invoked! If you set this up and remember to invoke config.parse(), all commandline - arguments will play nicely together: + arguments will play nicely together. This is done automatically for you + if you're using the bootstrap module's initialize wrapper. % main.py -h usage: main.py [-h] @@ -67,54 +70,53 @@ import argparse import logging import os import pprint -import re import sys -from typing import Any, Dict, List +from typing import Any, Dict, List, Optional # This module is commonly used by others in here and should avoid # taking any unnecessary dependencies back on them. -# Note: at this point in time, logging hasn't been configured and -# anything we log will come out the root logger. - - -class LoadFromFile(argparse.Action): - """Helper to load a config file into argparse.""" - def __call__ (self, parser, namespace, values, option_string = None): - with values as f: - buf = f.read() - argv = [] - for line in buf.split(','): - line = line.strip() - line = line.strip('{') - line = line.strip('}') - m = re.match(r"^'([a-zA-Z_\-]+)'\s*:\s*(.*)$", line) - if m: - key = m.group(1) - value = m.group(2) - value = value.strip("'") - if value not in ('None', 'True', 'False'): - argv.append(f'--{key}') - argv.append(value) - parser.parse_args(argv, namespace) +# Defer logging messages until later when logging has been initialized. +saved_messages: List[str] = [] + +# Make a copy of the original program arguments. +program_name: str = os.path.basename(sys.argv[0]) +original_argv: List[str] = [arg for arg in sys.argv] + + +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. + + """ + + def _split_lines(self, text, width): + if text.startswith('RAW|'): + return text[4:].splitlines() + return argparse.HelpFormatter._split_lines(self, text, width) # A global parser that we will collect arguments into. -prog = os.path.basename(sys.argv[0]) args = argparse.ArgumentParser( description=None, - formatter_class=argparse.ArgumentDefaultsHelpFormatter, + formatter_class=OptionalRawFormatter, fromfile_prefix_chars="@", - epilog=f'-----------------------------------------------------------------------------\n{prog} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.\n-----------------------------------------------------------------------------' + epilog=f'{program_name} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.', ) + +# Keep track of if we've been called and prevent being called more +# than once. config_parse_called = False -# A global configuration dictionary that will contain parsed arguments -# It is also this variable that modules use to access parsed arguments -config: Dict[str, Any] = {} -# Defer logging messages until later when logging has been initialized. -saved_messages: List[str] = [] +# A global configuration dictionary that will contain parsed arguments. +# It is also this variable that modules use to access parsed arguments. +# This is the data that is most interesting to our callers; it will hold +# the configuration result. +config: Dict[str, Any] = {} +# It would be really nice if this shit worked from interactive python def add_commandline_args(title: str, description: str = ""): @@ -128,27 +130,39 @@ group = add_commandline_args( ) group.add_argument( '--config_loadfile', - type=open, - action=LoadFromFile, metavar='FILENAME', default=None, - help='Config file from which to read args in lieu or in addition to commandline.', + help='Config file (populated via --config_savefile) from which to read args in lieu or in addition to commandline.', ) group.add_argument( '--config_dump', default=False, action='store_true', - help='Display the global configuration on STDERR at program startup.', + help='Display the global configuration (possibly derived from multiple sources) on STDERR at program startup.', ) group.add_argument( '--config_savefile', type=str, metavar='FILENAME', default=None, - help='Populate config file compatible --config_loadfile to save config for later use.', + help='Populate config file compatible with --config_loadfile to save global config for later use.', +) +group.add_argument( + '--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 this so as to allow interoperability with programs that ' + + 'want to use their own argparse calls to parse their own, separate commandline args.' + ), ) +def overwrite_argparse_epilog(msg: str) -> None: + args.epilog = msg + + def is_flag_already_in_argv(var: str): """Is a particular flag passed on the commandline?""" for _ in sys.argv: @@ -157,31 +171,21 @@ def is_flag_already_in_argv(var: str): return False -def parse(entry_module: str) -> Dict[str, Any]: - """Main program should call this early in main()""" - global config_parse_called - if config_parse_called: - return config - config_parse_called = True - global saved_messages - - # If we're about to do the usage message dump, put the main module's - # argument group first in the list, please. +def reorder_arg_action_groups(entry_module: Optional[str]): + global program_name, args reordered_action_groups = [] - prog = sys.argv[0] - for arg in sys.argv: - if arg == '--help' or arg == '-h': - print(entry_module) - for group in args._action_groups: - if entry_module in group.title or prog in group.title: - reordered_action_groups.insert(0, group) - else: - reordered_action_groups.append(group) - args._action_groups = reordered_action_groups - - # Examine the environment variables to settings that match - # known flags. For a flag called --example_flag the corresponding - # environment variable would be called EXAMPLE_FLAG. + for group in args._action_groups: + if entry_module is not None and entry_module in group.title: # type: ignore + reordered_action_groups.append(group) + elif program_name in group.title: # type: ignore + reordered_action_groups.append(group) + else: + reordered_action_groups.insert(0, group) + return reordered_action_groups + + +def augment_sys_argv_from_environment_variables(): + global saved_messages usage_message = args.format_usage() optional = False var = '' @@ -205,10 +209,9 @@ def parse(entry_module: str) -> Dict[str, Any]: if env in os.environ: if not is_flag_already_in_argv(var): value = os.environ[env] - saved_messages.append( - f'Initialized from environment: {var} = {value}' - ) + saved_messages.append(f'Initialized from environment: {var} = {value}') from string_utils import to_bool + if len(chunks) == 1 and to_bool(value): sys.argv.append(var) elif len(chunks) > 1: @@ -216,10 +219,73 @@ def parse(entry_module: str) -> Dict[str, Any]: sys.argv.append(value) var = '' env = '' + + +def augment_sys_argv_from_loadfile(): + global saved_messages + loadfile = None + saw_other_args = False + grab_next_arg = False + for arg in sys.argv[1:]: + if 'config_loadfile' in arg: + pieces = arg.split('=') + if len(pieces) > 1: + loadfile = pieces[1] + else: + grab_next_arg = True + elif grab_next_arg: + loadfile = arg + else: + saw_other_args = True + + if loadfile is not None: + if not os.path.exists(loadfile): + raise Exception( + f'ERROR: --config_loadfile argument must be a file, {loadfile} not found.' + ) + if saw_other_args: + msg = f'Augmenting commandline arguments with those from {loadfile}.' else: - next + msg = f'Reading commandline arguments from {loadfile}.' + print(msg, file=sys.stderr) + saved_messages.append(msg) + + with open(loadfile, 'r') as rf: + newargs = rf.readlines() + newargs = [arg.strip('\n') for arg in newargs if 'config_savefile' not in arg] + sys.argv += newargs + + +def parse(entry_module: Optional[str]) -> Dict[str, Any]: + """Main program should call this early in main(). Note that the + bootstrap.initialize wrapper takes care of this automatically. - # Parse (possibly augmented) commandline args with argparse normally. + """ + global config_parse_called + if config_parse_called: + return config + global saved_messages + + # If we're about to do the usage message dump, put the main + # module's argument group last in the list (if possible) so that + # when the user passes -h or --help, it will be visible on the + # screen w/o scrolling. + for arg in sys.argv: + if arg == '--help' or arg == '-h': + args._action_groups = reorder_arg_action_groups(entry_module) + + # Examine the environment for variables that match known flags. + # For a flag called --example_flag the corresponding environment + # variable would be called EXAMPLE_FLAG. If found, hackily add + # these into sys.argv to be parsed. + augment_sys_argv_from_environment_variables() + + # Look for loadfile and read/parse it if present. This also + # works by jamming these values onto sys.argv. + augment_sys_argv_from_loadfile() + + # Parse (possibly augmented, possibly completely overwritten) + # commandline args with argparse normally and populate config. known, unknown = args.parse_known_args() config.update(vars(known)) @@ -227,14 +293,25 @@ def parse(entry_module: str) -> Dict[str, Any]: # future argument parsers. For example, unittest_main in python # has some of its own flags. If we didn't recognize it, maybe # someone else will. + if len(unknown) > 0: + if config['config_rejects_unrecognized_arguments']: + raise Exception( + f'Encountered unrecognized config argument(s) {unknown} with --config_rejects_unrecognized_arguments enabled; halting.' + ) + saved_messages.append(f'Config encountered unrecognized commandline arguments: {unknown}') sys.argv = sys.argv[:1] + unknown - if config['config_savefile']: - with open(config['config_savefile'], 'w') as wf: - wf.write("\n".join(sys.argv[1:])) + # Check for savefile and populate it if requested. + savefile = config['config_savefile'] + if savefile and len(savefile) > 0: + with open(savefile, 'w') as wf: + wf.write("\n".join(original_argv[1:])) + # Also dump the config on stderr if requested. if config['config_dump']: dump_config() + + config_parse_called = True return config @@ -248,6 +325,7 @@ def dump_config(): """Print the current config to stdout.""" print("Global Configuration:", file=sys.stderr) pprint.pprint(config, stream=sys.stderr) + print() def late_logging():