limit-conn report error attribute does not exist

https://github.com/apache/apisix/pull/9663/files

install depends

redis

install redis and start the redis service

$ sudo apt install redis                                                                                                  100 [09:23:03]
[sudo] password for guohao:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
redis is already the newest version (5:6.0.16-1ubuntu1).
The following package was automatically installed and is no longer required:
  openjdk-11-jre
Use 'sudo apt autoremove' to remove it.
0 upgraded, 0 newly installed, 0 to remove and 17 not upgraded.

test the redis

$ redis-cli -h localhost
localhost:6379> set a test
OK
localhost:6379> get a
"test"

enable APISIX stream proxy

update the conf/config-default.yaml

diff --git a/conf/config-default.yaml b/conf/config-default.yaml
index e40dc174..3d8dd4c4 100755
--- a/conf/config-default.yaml
+++ b/conf/config-default.yaml
@@ -73,15 +73,15 @@ apisix:
                                 # radixtree_uri_with_parameter: similar to radixtree_uri but match URI with parameters. See https://github.com/api7/lua-resty-radixtree/#parameters-in-path for more details.
     ssl: radixtree_sni          # radixtree_sni: match route by SNI

-  # stream_proxy:                 # TCP/UDP L4 proxy
-  #   only: true                  # Enable L4 proxy only without L7 proxy.
-  #   tcp:
-  #     - addr: 9100              # Set the TCP proxy listening ports.
-  #       tls: true
-  #     - addr: "127.0.0.1:9101"
-  #   udp:                        # Set the UDP proxy listening ports.
-  #     - 9200
-  #     - "127.0.0.1:9201"
+  stream_proxy:                 # TCP/UDP L4 proxy
+     only: true                  # Enable L4 proxy only without L7 proxy.
+     tcp:
+       - addr: 9100              # Set the TCP proxy listening ports.
+         tls: true
+       - addr: "127.0.0.1:9101"
+     udp:                        # Set the UDP proxy listening ports.
+       - 9200
+       - "127.0.0.1:9201"

   # dns_resolver:                 # If not set, read from `/etc/resolv.conf`
   #   - 1.1.1.1
@@ -141,7 +141,7 @@ nginx_config:                     # Config for render the template to generate n
   # user: root                    # Set the execution user of the worker process. This is only
                                   # effective if the master process runs with super-user privileges.
   error_log: logs/error.log       # Location of the error log.
-  error_log_level:  warn          # Logging level: info, debug, notice, warn, error, crit, alert, or emerg.
+  error_log_level:  debug         # Logging level: info, debug, notice, warn, error, crit, alert, or emerg.
   worker_processes: auto          # Automatically determine the optimal number of worker processes based

create proxy

create a proxy and enable the limit-conn plugin with conn 1.

curl http://127.0.0.1:9180/apisix/admin/stream_routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "plugins": {
    "limit-conn": {
      "conn": 5,
      "burst": 0,
      "default_conn_delay": 0.1,
      "rejected_code": 503,
      "key_type": "var",
      "key": "remote_addr"
    }
  },
  "upstream": {
    "type": "none",
    "nodes": {
      "127.0.0.1:6379": 1
    }
  }
}
'

reload the APISIX instance

$ make reload                                                                                                                 [09:24:37]
[ info ] reload -> [ Start ]
/home/guohao/apisix/bin/apisix reload
/usr/local/openresty//luajit/bin/luajit ./apisix/cli/apisix.lua reload
Warning! Current maximum number of open file descriptors [1024] is not greater than 1024, please increase user limits by execute 'ulimit -n <new user limits>' , otherwise the performance is low.
[ info ] reload -> [ Done ]

test the proxy

test the stream proxy

$ 2023/07/10 18:35:08 [info] 40958#1379024: *542041 [lua] timers.lua:39: run timer[plugin#server-info], context: ngx.timer
2023/07/10 18:35:08 [info] 40956#1379020: *541986 client disconnected, bytes from/to client:47/171634, bytes from/to upstream:171634/47
2023/07/10 18:35:08 [info] 40956#1379020: *541986 stream [lua] init.lua:1114: stream_log_phase(): enter stream_log_phase while proxying connection, client: 127.0.0.1, server: 127.0.0.1:9101, upstream: "127.0.0.1:6379", bytes from/to client:47/171634, bytes from/to upstream:171634/0
2023/07/10 18:35:08 [debug] 40956#1379020: *541986 stream [lua] init.lua:125: phase_func(): request latency is nil
2023/07/10 18:35:09 [info] 40958#1379024: *542073 [lua] timers.lua:39: run timer[plugin#server-info], context: ngx.timer                                                                                           [09:24:53]
localhost:9101> set key test
OK
localhost:9101> get key
"test"

can’t reproduce the error log.

...
2023/07/10 09:26:19 [info] 6971#6971: *242376 stream [lua] init.lua:1114: stream_log_phase(): enter stream_log_phase while proxying connection, client: 127.0.0.1, server: 127.0.0.1:9101, upstream: "127.0.0.1:6379", bytes from/to client:117/18626, bytes from/to upstream:18626/0
2023/07/10 09:26:19 [debug] 6971#6971: *242376 stream [lua] init.lua:125: phase_func(): request latency is nil
...

update the config-default.yaml again.

-# xrpc:
-#   protocols:
-#     - name: pingpong
+xrpc:
+   protocols:
+     - name: redis
+

and create a router again

$ curl http://127.0.0.1:9180/apisix/admin/stream_routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "plugins": {
    "limit-conn": {
      "conn": 5,
      "burst": 0,
      "default_conn_delay": 0.1,
      "rejected_code": 503,
      "key_type": "var",
      "key": "remote_addr"
    }
  },
  "upstream": {
    "type": "none",
    "nodes": {
      "127.0.0.1:6379": 1
    }
  },
  "protocol": {
    "name": "redis"
  }
}
'

and the log error

...
2023/07/10 18:30:34 [error] 40018#1373140: *526473 failed to run log_by_lua*: ...ohao/workspace/apisix/apisix/plugins/limit-conn/init.lua:122: attempt to perform arithmetic on field 'request_time' (a nil value)
stack traceback:
	...ohao/workspace/apisix/apisix/plugins/limit-conn/init.lua:122: in function 'phase_func'
	/Users/guohao/workspace/apisix/apisix/plugin.lua:1134: in function 'run_plugin'
	/Users/guohao/workspace/apisix/apisix/init.lua:1116: in function 'stream_log_phase'
	log_by_lua(nginx.conf:113):2: in main chunk while prereading client data, client: 127.0.0.1, server: 127.0.0.1:9101
2023/07/10 18:30:35 [info] 40020#1373151: *526570 [lua] timers.lua:39: run timer[plugin#server-info], context: ngx.timer

At present, the reason for the two differences is unknown, and it takes time to look at the code.

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