ocrd_utils.config

Complexity

Total Complexity

26

Size/Duplication

Total Lines	168
Duplicated Lines	0 %

Importance

Changes

0

10 Methods

Rating	Name	Duplication	Size	Complexity
A	OcrdEnvConfig.has_default()	0	4	2
A	OcrdEnvConfig.describe()	0	4	2
A	OcrdEnvVariable.describe()	0	13	5
A	OcrdEnvConfig.add()	0	3	1
A	OcrdEnvConfig.raw_value()	0	4	2
A	OcrdEnvVariable.__init__()	0	21	2
A	OcrdEnvConfig.is_set()	0	4	2
A	OcrdEnvVariable.__str__()	0	2	1
B	OcrdEnvConfig.__getattr__()	0	14	6
A	OcrdEnvConfig.__init__()	0	2	1

"""
Most behavior of OCR-D is controlled via command-line flags or keyword args.
Some behavior is global or too cumbersome to handle via explicit code and
better solved by using environment variables.

OcrdEnvConfig is a base class to make this more streamlined, to be subclassed
in the `ocrd` package for the actual values
"""

from os import environ
from pathlib import Path
from textwrap import fill, indent

class OcrdEnvVariable():

    def __init__(self, name, description, parser=str, validator=lambda val: True, default=[False, None]):
        """
        An environment variable for use in OCR-D.

        Args:
            name (str): Name of the environment vairable
            description (str): Description of what the variable is used for.

        Keyword Args:
            parser (callable): Function to transform the raw (string) value to whatever is needed.
            validator (callable): Function to validate that the raw (string) value is parseable.
            default (tuple(bool, any)): 2-tuple, first element is a bool whether there is a default
                value defined and second element contains that default value, which can be a callable
                for defered evaluation
        """
        self.name = name
        self.description = description
        self.parser = parser
        self.validator = validator
        self.has_default = default[0]
        self.default = default[1]

    def __str__(self):
        return f'{self.name}: {self.description}'

    def describe(self, wrap_text=True, indent_text=True):
        desc = self.description
        if self.has_default:
            default = self.default() if callable(self.default) else self.default
            desc += f' (Default: "{default}")'
        ret = ''
        ret  = f'{self.name}\n'
        if wrap_text:
            desc = fill(desc, width=50)
        if indent_text:
            ret = f'  {ret}'
            desc = indent(desc, '    ')
        return ret + desc

class OcrdEnvConfig():

    def __init__(self):
        self._variables = {}

    def add(self, name, *args, **kwargs):
        self._variables[name] = OcrdEnvVariable(name, *args, **kwargs)
        return self._variables[name]

    def has_default(self, name):
        if not name in self._variables:
            raise ValueError(f"Unregistered env variable {name}")
        return self._variables[name].has_default

    def describe(self, name, *args, **kwargs):
        if not name in self._variables:
            raise ValueError(f"Unregistered env variable {name}")
        return self._variables[name].describe(*args, **kwargs)

    def __getattr__(self, name):
        if not name in self._variables:
            raise ValueError(f"Unregistered env variable {name}")
        var_obj = self._variables[name]
        try:
            raw_value = self.raw_value(name)
        except KeyError as e:
            if var_obj.has_default:
                raw_value = var_obj.default() if callable(var_obj.default) else var_obj.default
            else:
                raise e
        if not var_obj.validator(raw_value):
            raise ValueError(f"'{name}' set to invalid value '{raw_value}'")
        return var_obj.parser(raw_value)

    def is_set(self, name):
        if not name in self._variables:
            raise ValueError(f"Unregistered env variable {name}")
        return name in environ

    def raw_value(self, name):
        if not name in self._variables:
            raise ValueError(f"Unregistered env variable {name}")
        return environ[name]

config = OcrdEnvConfig()

config.add('OCRD_METS_CACHING',
    description='If set to `true`, access to the METS file is cached, speeding in-memory search and modification.',
    validator=lambda val: val in ('true', 'false', '0', '1'),
    parser=lambda val: val in ('true', '1'))

config.add('OCRD_MAX_PROCESSOR_CACHE',
    description="Maximum number of processor instances (for each set of parameters) to be kept in memory (including loaded models) for processing workers or processor servers.",
    parser=int,
    default=(True, 128))

config.add("OCRD_PROFILE",
    description="""\
Whether to enable gathering runtime statistics
on the `ocrd.profile` logger (comma-separated):
- `CPU`: yields CPU and wall-time,
- `RSS`: also yields peak memory (resident set size)
- `PSS`: also yields peak memory (proportional set size)
""",
  validator=lambda val : all(t in ('', 'CPU', 'RSS', 'PSS') for t in val.split(',')),
  default=(True, ''))

config.add("OCRD_PROFILE_FILE",
    description="If set, then the CPU profile is written to this file for later peruse with a analysis tools like snakeviz")

config.add("OCRD_DOWNLOAD_RETRIES",
    description="Number of times to retry failed attempts for downloads of workspace files.",
    validator=int,
    parser=int)

def _ocrd_download_timeout_parser(val):
    timeout = val.split(',')
    if len(timeout) > 1:
        timeout = tuple(float(x) for x in timeout)
    else:
        timeout = float(timeout[0])
    return timeout

config.add("OCRD_DOWNLOAD_TIMEOUT",
    description="Timeout in seconds for connecting or reading (comma-separated) when downloading.",
    parser=_ocrd_download_timeout_parser)

config.add("OCRD_NETWORK_SERVER_ADDR_PROCESSING",
        description="Default address of Processing Server to connect to (for `ocrd network client processing`).",
        default=(True, ''))

config.add("OCRD_NETWORK_SERVER_ADDR_WORKFLOW",
        description="Default address of Workflow Server to connect to (for `ocrd network client workflow`).",
        default=(True, ''))

config.add("OCRD_NETWORK_SERVER_ADDR_WORKSPACE",
        description="Default address of Workspace Server to connect to (for `ocrd network client workspace`).",
        default=(True, ''))

config.add("HOME",
    description="Directory to look for `ocrd_logging.conf`, fallback for unset XDG variables.",
    # description="HOME directory, cf. https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html",
    validator=lambda val: Path(val).is_dir(),
    parser=lambda val: Path(val),
    default=(True, lambda: Path.home()))

config.add("XDG_DATA_HOME",
    description="Directory to look for `./ocrd/resources.yml` (i.e. `ocrd resmgr` user database)",
    default=(True, lambda: Path(config.HOME, '.local/share')))

config.add("XDG_CONFIG_HOME",
    description="Directory to look for `./ocrd-resources/*` (i.e. `ocrd resmgr` data location)",
    default=(True, lambda: Path(config.HOME, '.config')))