kong.request.get_header - header length issue

[mpromny]

Summary

• Env: K8s
  • Deployment via Helm
• Kong version (2.4) - customized
• Kong-python-pdk - 0.25
  • each plugin as a microservice approach
• Issue:
  • Python server is unable to get headers larger than 1024 characters

Additional Details & Logs

• Error:

  [info] 30#0: *17 [py:32] DEBG - [16:51:56] rpc: #32 return: {'Data': {'Method': 'kong.request.get_header', 'Args': ('x-test-header',)}, 'EventId': 5}, context: ngx.timer
  [error] 30#0: *124 recv() failed (104: Connection reset by peer), client: 100.97.23.0, server: kong, request: "GET /foo HTTP/1.1", host: "kong-test.example.com"

• Error description:

  • It seems that python plugin server restarts/fails while it has to read headers longer than 1024 characters.
  • If an error occurs, Kong processes the request without involving Kong python server

• Assumptions: I could be wrong but maybe it's somehow connected with listener definition: https://github.com/Kong/kong-python-pdk/blob/master/kong_pdk/listener.py

Steps To Reproduce

1. Load plugin as configmap via helm or add directly to the docker image

Plugin:

#!/usr/bin/python3
import os
import time
import kong_pdk.pdk.kong as kong

Schema = (
    {"message": {"type": "string"}}
)

version = '0.1.0'
priority = 0

class Plugin(object):

    def __init__(self, config):
        self.config = config

    def access(self, kong: kong):

        message = "hello"
        if 'message' in self.config:
            message = self.config['message']

        # Get Authorization Header from the request
        try:
            header_auth, err_auth = kong.request.get_header("x-test-header")
            if err_auth:
                kong.log.err(err_auth)
        except Exception as e:
            kong.log.err(e)
            kong.response.exit(403,"Too long header")

        # Authorization header is empty
       try:
           kong.service.request.set_header("x-new-header", str(header_auth))
       except Exception as e:
           kong.log.err(e)
           kong.response.exit(403,str(e))

# add below section to allow this plugin optionally be running in a dedicated process
if __name__ == "__main__":
    from kong_pdk.cli import start_dedicated_server
    start_dedicated_server("py-hello", Plugin, version, priority)

2.Modify Kong configuration:

  log_level: debug
  plugins: bundled, py-hello 
  pluginserver_names: py 

  pluginserver_py_socket: /usr/local/kong/py_hello.sock
  pluginserver_py_start_cmd: /opt/test/py-hello.py -vvv
  pluginserver_py_query_cmd: /opt/test/py-hello.py -dump

3. Load plugin

   apiVersion: configuration.konghq.com/v1
   kind: KongClusterPlugin
   metadata:
   name: py-hello
   annotations:
   kubernetes.io/ingress.class: kong
   labels:
   global: "true"
   plugin: py-hello

4. Execute: curl -L -X GET https://kong-test.example.com/foo \ -H 'x-test-header: 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'

[fffonion]

Thanks for reporting @mpromny , this has been fixed and will be included in next release of kong-python-pdk.

[mpromny]

@fffonion Thanks for fixing so swiftly.