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config.py

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  • config.py 14.08 KiB
    #!/usr/bin/env python 
    #-*- coding: utf-8 -*-
    
    import os, getpass, sys
    import toml
    from pathlib import Path
    from logging.config import dictConfig
    from typing import List
    import collections.abc
    
    
    # Affects config directories etc
    APPLICATION_NAME = "stechuhr-server"
    
    # Do not change here, just use an override instead
    DEFAULT_CONFIG = """
    [application]
    # Warning: setting this to true can will display all visitor movments when the
    # server adress is visited. Only use for debugging!
    expose_visitor_data = false
    expose_current_visitor_number = false
    
    [database]
    # sqlite db path, use ":memory:" for RAM db
    path = "visitors.db"
    
    # A list of possible regex patterns for the id (logical OR!)
    id_patterns = [
        "^806[A-Z0-9]{9}04$",
        "^FB6A1E60$",
        "^FB6D6950$",
        "^FB6A9DE0$",
        "^FB67D500$",
    ]
    
    # minimum and maximum lengths for the received strings
    min_entrance_length = 1
    max_entrance_length = 128
    min_location_length = 1
    max_location_length = 128
    
    [retention]
    # how old is data allowed to be (in days)
    duration = 365
    """
    
    # Config for the logger, there should be no need to make
    # manual changes here
    dictConfig({
        'version': 1,
        'formatters': {'default': {
            'format': '[%(asctime)s] %(levelname)s in %(module)s: %(message)s',
        }},
        'handlers': {'wsgi': {
            'class': 'logging.StreamHandler',
            'stream': 'ext://flask.logging.wsgi_errors_stream',
            'formatter': 'default'
        }},
        'root': {
            'level': 'INFO',
            'handlers': ['wsgi']
        }
    })
    
    
    def this_or_else(this: str, other: str) -> str:
        """
        Return this appended with the application name
        if this is a non-empty string otherwise return other
        """
        if this is None or this.strip() == "":
            return other
        else:
            return "{}/{}".format(this, APPLICATION_NAME)
    
    
    def get_home() -> str:
        """
        Get the home directory from the environment variable
        """
        return os.environ.get("HOME")
    
    
    def get_config_directories() -> List[dict]:
        """
        Returns a list of potential directories where the config could be stored.
        Existence of the directories is _not_ checked
        """
    
        # Generate a etc directory (usually /etc/stechuhr-server)
        etc_directory = "/etc/{}".format(APPLICATION_NAME)
    
        # Get the default config dir (usually /home/user/.config/stechuhr-server)
        default_config_home = "{}/.config/{}".format(get_home(), APPLICATION_NAME)
    
        # Unless the XDG_CONFIG_HOME environment variable has been set, then use this instead
        default_config_home = this_or_else(os.environ.get("XDG_CONFIG_HOME"), default_config_home)
    
        # Create the list of directories
        config_directories = [
            { "path": Path(etc_directory), "kind": "default", "source": None },
            { "path": Path(default_config_home), "kind": "default", "source": None }
        ]
    
        # If the STECHUHR_SERVER_CONFIG_PATH environment variable exists append to list
        key = "{}_CONFIG_DIR".format(APPLICATION_NAME.upper()).replace("-", "_").replace(" ", "_")
        if os.getenv(key) is not None:
            env_dir = { "path": Path(os.getenv(key)), "kind": "env", "source": key }
            config_directories.append(env_dir)
    
        return config_directories
    
    def get_potential_config_file_paths() -> List[dict]:
        """
        Returns a list of config file paths in reverse order of importance
        (last overrides first, non-existing paths may be contained)
        """
    
        config_paths = []
    
        for directory in get_config_directories():
            for path in sorted(directory["path"].glob('*.toml')):
                path = { "path": path, "kind": "default", "source": None }
                config_paths.append(path)
    
        # If the STECHUHR_SERVER_CONFIG_PATH environment variable exists append to list
        key = "{}_CONFIG_PATH".format(APPLICATION_NAME.upper()).replace("-", "_").replace(" ", "_")
        if os.getenv(key) is not None:
            env_path = { "path": Path(os.getenv(key)), "kind": "env", "source": key }
            config_paths.append(env_path)
    
        # Add information about a paths existence
        for p in config_paths:
            p["exists"] = p["path"].is_file()
    
        return config_paths
    
    def get_existing_config_file_paths() -> List[Path]:
        """
        Returns a list of existing config file paths in reverse order of importance
        (last overrides first)
        """
    
        return [p["path"] for p in get_potential_config_file_paths() if p["path"].is_file()]
    
    def has_no_existing_config() -> bool:
        """
        Returns true if there is no existing config
        """
        return len(get_existing_config_file_paths()) == 0
    
    def merge(this: dict, that: dict) -> dict:
        """
        Merge dict this in to dict that
        """
        for key, value in that.items():
            if isinstance(value, collections.abc.Mapping):
                this[key] = merge(this.get(key, {}), value)
            else:
                this[key] = value
        return this
    
    def initialize_config(logger=None) -> dict:
        """
        Initialize a configuration. If none exists, create a default one
        """
        config = toml.loads(DEFAULT_CONFIG)
    
        # Return if there is no other config
        if has_no_existing_config():
            if logger is not None:
                logger.warning("Using default configuration, create an override by running config create")
            else:
                print("Using default configuration, create an override by running config create")
            return config
    
        if logger is not None:
            logger.info("Reading Configs in this order:")
            logger.info("Config [1]: DEFAULT_CONFIG (hardcoded)")
        else:
            print("Reading Configs in this order:")
            print("Config [1]: DEFAULT_CONFIG (hardcoded)")
    
        # Read all existing configs in order and merge/override the default one
        for i, p in enumerate(get_existing_config_file_paths()):
            next_config = read_config(p)
            config = merge(config, next_config)
            if logger is not None:
                logger.info("Config [{}]: {} (overrides previous configs)".format(i+2, p))
            else:
                print("Config [{}]: {} (overrides previous configs)".format(i+2, p))
    
        return config
    
    
    def read_config(config_path: str) -> dict:
        """
        Read a config.toml from the given path,
        return a dict containing the config
        """
        with open(str(config_path), "r", encoding="utf-8") as f:
            config = toml.load(f)
        return config
    
    
    def main():
        """
        Gets run only if config.py is called directly or via `poetry run config`
        Entry point for the CLI application
        """
        import sys
    
        commands = {
            "default" : print_default,
            "paths": print_paths,
            "directories": print_directories,
            "create": create_config,
            "test": test
        }
    
    
    
        if len(sys.argv) == 1:
            print_help()
            exit()
    
        command_args = [c for c in sys.argv[1:] if not c.strip().startswith("-")]
        short_options = [c.lstrip("-") for c in sys.argv[1:] if c.strip().startswith("-") and not c.strip().startswith("--")]
        long_options = [c.lstrip("--") for c in sys.argv[1:] if c.strip().startswith("--")]
    
    
        if len(command_args) == 1:
            command = sys.argv[1]
            if not any([c.startswith(command.strip().lower()) for c in commands.keys()]):
                print_help()
                exit()
            elif len([c for c in commands.keys() if c.startswith(command.strip().lower())]) > 1:
                print("Ambiguous Input: There are {} commands starting with \"{}\": {}".format(
                    len([c for c in commands.keys() if c.startswith(command.strip().lower())]),
                    command,
                    ", ".join([c for c in commands.keys() if c.startswith(command.strip().lower())])
                ))
            else:
                choice = [c for c in commands.keys() if c.startswith(command.strip().lower())][0]
                if "h" in short_options or "help" in long_options:
                    print("Help: config {}".format(commands[choice].__name__))
                    print(commands[choice].__doc__)
                else:
                    commands[choice]()
    
        else:
            print_help()
    
    
    def test():
        """
        Runs the config initialization as it would in production, prints out the 
        order in which the config files are read and spits out the final resulting
        toml config
        """
        import pprint
        config = initialize_config()
        print("\nvvvvvvvvvvvvv Below is the resulting config vvvvvvvvvvvvv\n")
        print(toml.dumps(config))
    
    def print_default():
        """
        Print default config
        """
        print(DEFAULT_CONFIG)
    
    def print_paths():
        paths = get_potential_config_file_paths()
        if paths is not None:
            for p in paths:
                if p["kind"] == "env":
                    if p["exists"]:
                        print("{} (set by environment variable {})".format(p["path"], p["source"]))
                    else:
                        print("{} (set by environment variable {}, but doesn't exist)".format(p["path"], p["source"]))
                else:
                    if p["exists"]:
                        print("{}".format(p["path"]))
                    else:
                        print("{} (doesn't exist yet)".format(p["path"]))
        else:
            print("There are no paths..")
    
    def print_directories():
        """
        Prints a list of directories where configs are searched for.
        Lower directories override higher directories.
        """
        directories = get_config_directories()
        if directories is not None:
            for d in directories:
                if d["kind"] == "env":
                    print("{} (set by environment variable {})".format(d["path"], d["source"]))
                else:
                    print("{}".format(d["path"]))
        else:
            print("There are no directories..")
    
    def create_config():
        """
        Interactivally create a config directory with a default config in it.
        """
        helptext = """Configs are read from the following directories (later overrides earlier):
    1. DEFAULT_CONFIG (use config default to inspect)
    2. /etc/stechuhr-server/*.toml (in alphabetical order)
    3. $XDG_CONFIG_HOME/stechuhr-server/*.toml (in alphabetical order)
    4. $STECHUHR_SERVER_CONFIG_DIR/*.toml (in alphabetical order)
    5. $STECHUHR_SERVER_CONFIG_PATH (final override)
    """
        print(helptext)
        print()
        print("Select one of the following options to create a new config:")
        config_directories = get_config_directories()
        for i, p in enumerate(config_directories):
            # Create a source string describing the origin of the directory
            if p["kind"] == "env":
                source = "set via environment variable {}, ".format(p["source"])
            else:
                source = ""
            # Display some options
            if p["path"].is_dir():
                config_path = Path("{}/{}".format(p, "00-config.toml"))
                if not config_path.is_file():
                    print("  [{}] {} ({}create 00-config.toml there)".format(i, p["path"], source))
                else:
                    print("  [{}] {} ({}override existing 00-config.toml!)".format(i, p["path"], source))
            elif p["path"].is_file():
                pass
            else:
                print("  [{}] {} ({}dir doesn't exist: create, then write 00-config.toml there)".format(i, p["path"], source))
        print("  [x] Do nothing")
        print()
    
        # Collect the selection input
        selection = None
        while selection is None or not selection in [str(i) for i, p in enumerate(config_directories)]:
            selection = input("Select one of the above: ")
            if selection.lower() in ["x"]:
                break
    
        # If nothing has been selected, exit
        if selection.lower() == "x":
            exit()
    
        # Store the selected directory here
        selection = config_directories[int(selection)]
    
        # Create the directory if it doesn't exist yet
        selection.mkdir(mode=0o755, parents=True, exist_ok=True)
        config_path = Path("{}/{}".format(selection, "00-config.toml"))
    
        # If the 00-config.toml already exists, ask whether it shall be moved to 00-config.toml.old
        if config_path.is_file():
            # Create an alternate config path, incrementing up if .old already exists
            alt_config_path = None
            i = 1
            while alt_config_path is None or alt_config_path.exists():
                if i == 1:
                    alt_config_path = Path("{}.old".format(config_path))
                else:
                    alt_config_path = Path("{}.old{}".format(config_path, i))
                i += 1
    
            # Ask for confirmation
            confirmation = None
            while confirmation is None or not confirmation.lower().strip() in ["y", "n"]:
                confirmation = input("Move existing file at \"{}\" to \"{}\"? [Y/n]:\t".format(config_path, alt_config_path))
            if confirmation.lower().strip() != "y":
                exit()
            else:
                config_path.rename(alt_config_path)
                print("Moved existing file \"{}\" to \"{}\"".format(config_path, alt_config_path))
    
        # Create the config.toml or display a hint if the permissions don't suffice
        try:
            config_path.write_text(DEFAULT_CONFIG)
        except PermissionError as e:
            print()
            print("Error: Didn't have the permissions to write the file to {}".format(config_path), file=sys.stderr)
            print("       Directory \"{}\" belongs to user {} (was running as user {})".format(selection, selection.owner(), getpass.getuser()), file=sys.stderr)
            print()
            print("Hint:  Change the owner of the directory temporarily to {} or run {} config create with more permissions".format(getpass.getuser(), APPLICATION_NAME))
            exit()
        print("Default Config has been written to {}".format(config_path))
    
    
    
    def print_help():
        helptext = """========= {} CONFIG =========
    
    Helper tool for managing and installing a stechuhr-server config.
    
    Configs are read from the following directories (later overrides earlier):
    1. DEFAULT_CONFIG (see below)
    2. /etc/stechuhr-server/*.toml (in alphabetical order)
    3. $XDG_CONFIG_HOME/stechuhr-server/*.toml (in alphabetical order)
    4. $STECHUHR_SERVER_CONFIG_DIR/*.toml (in alphabetical order)
    5. $STECHUHR_SERVER_CONFIG_PATH (final override)
    
    Commands:
        create  . . . . . Interactivly create a default config file
        default . . . . . Prints default config.toml to stdout
        directories . . . Prints which config directories are read
        paths . . . . . . Prints which config files are read
        test  . . . . . . Read in the configs and print the resulting combined toml
        """.format(APPLICATION_NAME.upper())
    
        print(helptext)
    
    if __name__ == "__main__":
        main()