cli_utils.py

#!/usr/bin/env python3
 

 
"""
Utility functions for the ConditionsDB command line interface
"""
 
import re
from basf2 import B2ERROR
 
 
class ItemFilter:
    """
    Class to filter a list of tags/payloads/iovs with a common interface, that
    is same set of parameters and easy handling of checking.
 
    This class defines -f,--filter/-e,--exclude/-r/--regex parameters which will
    be added to a :class:`argparse.ArgumentParser` when calling `add_arguments`.
    """
 
    def __init__(self, args):
        """initialization, just remember the arguments or parser"""
        ## arguments, either :class:`argparse.ArgumentParser` on initialization
        # or :class:`argparse.Namespace` after argument parsing
        self._args = args
        ## regular expression for filtering items which don't match
        self._filter = None
        ## regular expression for excluding items which match
        self._exclude = None
 
    def add_arguments(self, name):
        """
        Add arguments to the parser
 
        Parameters:
          name: Name of the objects to be filtered in the help text
        """
        self._args.add_argument("-f", "--filter", metavar="SEARCHTERM",
                                help=f"only {name} matching this pattern will be included. Pattern is case insensitive")
        self._args.add_argument("-e", "--exclude", default=None, type=str,
                                help=f"{name} matching this pattern will be excluded. Pattern is case insensitive")
        self._args.add_argument("-r", "--regex", action="store_true", default=False,
                                help="if given, --filter or --exclude options will be "
                                "interpreted as a python regular expression "
                                "(see https://docs.python.org/3/library/re.html)")
 
    def __str__(self):
        """
        Convert to a text representation of the form ' [regex filter=TERM exclude=TERM]'.
 
        The space in the beginning is intentional to allow easy adding to a
        description without extra spaces
 
        If no filtering is performed an empty string is returned. If the
        patterns are non-regex (without --regex), the regex will be missing in
        the string.  If one of the --filter/--exclude option was not given, that
        part is removed from the string
        """
        text = []
        for attribute in ["filter", "exclude"]:
            term = getattr(self._args, attribute, None)
            if term is not None:
                text.append(f"{attribute}={term}")
        if not text:
            return ""
        if getattr(self._args, "regex", False):
            text.insert(0, "regex")
 
        return f" [{' '.join(text)}]"
 
    def check_arguments(self):
        """
        Check if the arguments are valid (only if --regex is given) and compile into
        regular expressions. If False is returned there was an error with the
        regular expressions.
        """
        for attribute in ["filter", "exclude"]:
            term = getattr(self._args, attribute, None)
            if term is not None:
                try:
                    if not getattr(self._args, "regex", False):
                        term = re.escape(term)
                    setattr(self, "_"+attribute, re.compile(term, re.IGNORECASE))
                except Exception as e:
                    B2ERROR(f"--{attribute}: '{term}' is not a valid regular expression: {e}'")
                    return False
        return True
 
    def check(self, item):
        """
        Check an item. True is returned if it should be kept, False if it is
        filtered out or excluded.
 
        Parameters:
          item: item to be filtered
        """
        if self._filter is not None and not self._filter.search(item):
            return False
        if self._exclude is not None and self._exclude.search(item):
            return False
        return True