JSON schema v4 for Python's logging.config.dictConfig: https://docs.python.org/3/library/logging.config.html#logging-config-dictschema

schema.json

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "title": "JSON schema for Python logging.config.dictConfig",
  "type": "object",
  "required": ["version"],
  "properties": {
    "version": {"type": "integer", "enum": [1]},
    "formatters": {
      "type": "object",
      "patternProperties": {
        "^[a-zA-Z0-9._-]+$": {
          "type": "object",
          "properties": {
            "format": {"type": "string"},
            "datefmt": {"type": "string"}
          },
          "additionalProperties": false
        }
      }
    },

    "filters": {
      "type": "object",
      "patternProperties": {
        "^[a-zA-Z0-9._-]+$": {
          "type": "object",
          "properties": {
            "name": {"type": "string"}
          },
          "additionalProperties": false
        }
      }
    },

    "handlers": {
      "type": "object",
      "patternProperties": {
        "^[a-zA-Z0-9._-]+$": {
          "type": "object",
          "required": ["class"],
          "properties": {
            "class": {"type": "string"},
            "level": {"type": "string"},
            "formatter": {"type": "string"},
            "filters": {
              "type": "array",
              "items": {"type": "string"},
              "uniqueItems": true
            }
          }
        }
      }
    },

    "loggers": {
      "type": "object",
      "patternProperties": {
        "^[a-zA-Z0-9._-]+$": {
          "type": "object",
          "properties": {
            "level": {"type": "string"},
            "propagate": {"type": "boolean"},
            "filters": {
              "type": "array",
              "items": {"type": "string"},
              "uniqueItems": true
            },
            "handlers": {
              "type": "array",
              "items": {"type": "string"},
              "uniqueItems": true
            }
          }
        }
      }
    },

    "root": {
      "type": "object",
      "properties": {
        "level": {
          "type": "string",
          "enum": [ "CRITICAL", "ERROR", "WARNING", "INFO", "DEBUG" ]
        },
        "filters": {
          "type": "array",
          "items": {"type": "string"},
          "uniqueItems": true
        },
        "handlers": {
          "type": "array",
          "items": {"type": "string"},
          "uniqueItems": true
        }
      }
    },

    "incremental": {"type": "boolean"},
    "disable_existing_loggers": {"type": "boolean"}
  }
}

suggest adding to formaters to support formatting other than %:

     ...
     "formatters": {
     ...
         "properties": {
            "format": {"type": "string"},
            "datefmt": {"type": "string"},
            "style": {"type": "string", "enum": ["%", "{", "$"]}
          }
     ...