Exception Handling

[washcroft]

Hello, What is the intended behaviour of a plugin raising an exception?

e.g.

  "plugins": {
    "ext-plugin-pre-req": {
      "allow_degradation": false,
      "conf": [
        {
          "name": "netsuite-authenticator",
          "value": "this is invalid json config"
        }
       ]
      }
    }

    def config(self, conf: Any) -> Any:
        """
        Parse plugin configuration
        :param conf:
        :return:
        """
        try:
            conf_json = json.loads(conf)
        except ValueError as e:
            raise Exception("Configuration is invalid json")

        return conf_json

2022-10-07 07:11:42,257 - INFO - request type:2, len:1792
2022-10-07 07:11:42,260 - ERROR - execute plugin `netsuite-authenticator` AnyError, ('Configuration is invalid json',)
2022-10-07 07:11:42,260 - INFO - response type:2, len:16

However apisix ignores the plugin and continues with the request to the upstream. This same occurs even if the exception is thrown in the filter() method.

I would prefer the ability to control this behaviour and I was expecting allow_degredation in apisix config to control the behaviour, but it seems this only apply to the plugin runner process itself, not errors from the plugin.

In some cases I also see the following errors immediately after the starting the plugin in dev mode due to the config token caching mechanism.

2022-10-07 07:37:13,104 - INFO - request type:2, len:1792
2022-10-07 07:37:13,106 - ERROR - token `1` cache acquisition failed
2022-10-07 07:37:13,106 - INFO - response type:2, len:16

Again, apisix ignores the plugin and continues with the request to the upstream, but I would rather it didn't.

I believe this is happening because the plugin runner is always returning a successful RPC response, but the "action" in the response isn't set to either stop or rewrite, so apisix just assumes the plugin didn't want to do anything.

[SkyeYoung]

Hi, I checked the logic of the code. Let me try to answer these questions for you.

apisix ignores the plugin and continues with the request to the upstream

In python-plugin-runner.

1. https://github.com/apache/apisix-python-plugin-runner/blob/master/apisix/runner/plugin/core.py#L92-L94

   

2. https://github.com/apache/apisix-python-plugin-runner/blob/master/apisix/runner/server/handle.py#L83-L87

   

In apisix/plugins/ext-plugin.

1. https://github.com/apache/apisix/blob/master/apisix/plugins/ext-plugin/init.lua#L566

   

Since python-plugin-runner does not modify ty's original type RPC_HTTP_REQ_CALL, apisix ignores the error, which seems to be an implementation problem with python-plugin-runner. 🤔

Also, errors throwed by config() are only logged in the execute() of python-plugin-runner, but are not passed to the function that calls execute(), and so are not passed to apisix.

allow_degredation

If the ty type problem described above can be fixed, it should be possible to get some errors here so that the allow_degradation should behave appropriately. 🤔

I'm not familiar enough with the code. 😅 @bzp2010 Pls help me check this.