Description:
When I debug envoy with dubbo protocol, found this debug message appear once every minutes, I wonder how it works and who send this message.
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:134] dubbo decoder:17 bytes available
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:144] dubbo decoder:protocol dubbo, state OnTransportBegin, 17 bytes available
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:20] dubbo decoder: this is the dubbo heartbeat message
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/heartbeat_response.cc:20] buffer length 16
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:163] dubbo decoder:data length 1
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:134] dubbo decoder:1 bytes available
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:144] dubbo decoder:protocol dubbo, state OnTransportBegin, 1 bytes available
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:15] dubbo decoder: need more data for dubbo protocol
[2019-08-19 12:19:53.744][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:149] dubbo decoder:wait for data

Question:
I also found this error below, after heartbeat message, when next message comes, this error will happen, why?
[2019-08-19 12:20:53.794][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:134] dubbo decoder:18 bytes available
[2019-08-19 12:20:53.794][29][debug][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/decoder.cc:144] dubbo decoder:protocol dubbo, state OnTransportBegin, 18 bytes available
[2019-08-19 12:20:53.794][29][error][dubbo] [external/envoy/source/extensions/filters/network/dubbo_proxy/conn_manager.cc:132] [C44] dubbo error: invalid dubbo message magic number 20186
default_words: "kubernetes://dubboconsumer-fd56fc7d9-6m4m8.default"