elasticapm/instrumentation/packages/flask.py

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import logging

from elasticapm.instrumentation.packages.base import AbstractInstrumentedModule


class FlaskInstrumentation(AbstractInstrumentedModule):
    name = "flask"

    instrument_list = [("flask", "Flask.__init__")]

    creates_transactions = True

    def call(self, module, method, wrapped, instance, args, kwargs) -> None:
        from elasticapm.contrib.flask import ElasticAPM

        wrapped(*args, **kwargs)
        client = ElasticAPM(instance)
        instance.elasticapm_client = client
        self.instance = instance

    def uninstrument(self) -> None:
        """
        This is mostly here for testing. If we want to support live
        instrumenting and uninstrumenting, we'll need to also extend the
        `instrument()` method to add the signals removed here.
        """
        super().uninstrument()

        # Only remove signals during uninstrument if we auto-instrumented
        flask_app = getattr(self, "instance", None)
        if flask_app:
            client = flask_app.elasticapm_client
            from flask import signals

            signals.request_started.disconnect(client.request_started)
            signals.request_finished.disconnect(client.request_finished)
            # remove logging handler if it was added
            logger = logging.getLogger()
            for handler in list(logger.handlers):
                if getattr(handler, "client", None) is client.client:
                    logger.removeHandler(handler)
            self.instance = None