mozilla_schema_generator/matcher.py

# -*- coding: utf-8 -*-

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

from typing import Any

from .probes import Probe


class Matcher(object):
    table_group_key = "table_group"
    type_key = "type"
    contains_key = "contains"
    not_key = "not"
    any_key = "any"

    keywords = {contains_key, not_key, type_key, table_group_key, any_key}

    def __init__(self, match_obj: dict, *, _type=None, table_group=None):
        """
        table_group: required, which table that group belongs in
        type: optional, the type of the metrics

        All other fields are matched as exact matches,
        except for `contains` which checks that that value
        is in the associated array.
        """
        self.table_group = table_group or match_obj.get(self.table_group_key)
        self.type = _type or match_obj.get(self.type_key)

        self.matcher = {
            k: v
            for k, v in match_obj.items()
            if k not in {self.table_group_key, self.type_key}
        }

    def get_table_group(self):
        return self.table_group

    def matches(self, probe: Probe) -> bool:
        # Not a match if the types don't match
        if self.type and self.type != probe.get_type():
            return False

        for k, v in self.matcher.items():
            probe_value = probe.get(k)

            if not self._matches(v, probe_value):
                return False

            # Definitions are nested, check sub-fields (e.g. details)
            if isinstance(v, dict):
                for sub_k, sub_v in v.items():
                    if sub_k not in self.keywords and not self._matches(
                        sub_v, probe_value[sub_k]
                    ):
                        return False

        return True

    def clone(self, new_type=None, new_table_group=None):
        if new_table_group is None:
            new_table_group = self.table_group
        if new_type is None:
            new_type = self.type

        return Matcher(self.matcher, _type=new_type, table_group=new_table_group)

    @staticmethod
    def _matches(match_v: Any, probe_v: Any) -> bool:
        if isinstance(probe_v, set):
            probe_v = list(probe_v)

        # Not a match if this key isn't in the probe definition
        if probe_v is None:
            return False

        # Not a match if not an exact match of values (e.g. type=scalar vs. histogram)
        if not isinstance(match_v, dict):
            if match_v != probe_v:
                return False

        elif isinstance(match_v, dict):
            # Not a match if probe_v doesn't contain expected value
            if Matcher.contains_key in match_v:
                if match_v[Matcher.contains_key] not in probe_v:
                    return False

            # Not a match if matches the "not" value
            if Matcher.not_key in match_v:
                if match_v[Matcher.not_key] == probe_v:
                    return False

            # Match if any of the listed values match
            if Matcher.any_key in match_v:
                return probe_v in match_v[Matcher.any_key]
        return True