out_websocket: doc change with PR #3010 (#455)

Signed-off-by: Fenggang <[email protected]>

Author: ginobiliwang

pipeline/outputs/websocket.md

@@ -12,7 +12,6 @@ The **websocket** output plugin allows to flush your records into a WebSocket en
 | Format | Specify the data format to be used in the HTTP request body, by default it uses _msgpack_. Other supported formats are _json_, _json\_stream_ and _json\_lines_ and _gelf_. | msgpack |
 | json\_date\_key | Specify the name of the date field in output | date |
 | json\_date\_format | Specify the format of the date. Supported formats are _double_ and _iso8601_ \(eg: _2018-05-30T09:39:52.000681Z_\) | double |
-| idle\_interval | The interval that websocket output plugin would keep to decide if it is OK to reconnet to Websocket Server | 20 |
 
 ## Getting Started
 
@@ -48,12 +47,10 @@ In your main configuration file, append the following _Input_ & _Output_ section
     Port  80
     URI   /something
     Format json
-    Idle_interval 21
 ```
 
-Suggested configuration for Idle Interval is 20. Websocket plugin is working with tcp keepalive mode, please refer to [networking](https://docs.fluentbit.io/manual/v/master/administration/networking#configuration-options) section for details.
+Websocket plugin is working with tcp keepalive mode, please refer to [networking](https://docs.fluentbit.io/manual/v/master/administration/networking#configuration-options) section for details. Since websocket is a stateful plugin, it will decide when to send out handshake to server side, for example when plugin just begins to work or after connection with server has been dropped. In general, the interval to init a new websocket handshake would be less than the keepalive interval. With that stratgy, it could detect and resume websocket connetions. 
 
-By default, if there is no traffic for about 30 seconds, fluent-bit would abort the tcp connection. As a result, if websocket would like to send data to the same server again, it has to reconnect. This parameter is to help to determine if websocket need to reconnect or not.
 
 ## Testing
 
@@ -69,10 +66,12 @@ By default, if there is no traffic for about 30 seconds, fluent-bit would abort
     Name           websocket
     Match          *
     Host           127.0.0.1
-    Port           9000
+    Port           8080
     URI            /
     Format         json
-    Idle_interval  21
+    workers	   4
+    net.keepalive               on
+    net.keepalive_idle_timeout  30
 ```
 
 Once Fluent Bit is running, you can send some messages using the _netcat_:
@@ -84,27 +83,42 @@ $ echo '{"key 1": 123456789, "key 2": "abcdefg"}' | nc 127.0.0.1 5170; sleep 35;
 In [Fluent Bit](http://fluentbit.io) we should see the following output:
 
 ```bash
-bin/fluent-bit -c ../conf/out_ws.conf
-Fluent Bit v1.5.0
+bin/fluent-bit   -c ../conf/out_ws.conf
+Fluent Bit v1.7.0
 * Copyright (C) 2019-2020 The Fluent Bit Authors
 * Copyright (C) 2015-2018 Treasure Data
 * Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
 * https://fluentbit.io
 
-[2020/07/07 03:39:31] [ info] [storage] version=1.0.4, initializing...
-[2020/07/07 03:39:31] [ info] [storage] in-memory
-[2020/07/07 03:39:31] [ info] [storage] normal synchronization mode, checksum disabled, max_chunks_up=128
-[2020/07/07 03:39:31] [ info] [engine] started (pid=12734)
-[2020/07/07 03:39:31] [ info] [input:tcp:tcp.0] listening on 0.0.0.0:5170
-[2020/07/07 03:39:31] [ info] [out_ws] we have following parameter /, 127.0.0.1, 9000, 22
-[2020/07/07 03:39:31] [ info] [sp] stream processor started
-[2020/07/07 03:39:36] [ info] [out_ws] handshake for ws
-[2020/07/07 03:40:11] [ warn] [engine] failed to flush chunk '12734-1594107609.72852130.flb', retry in 6 seconds: task_id=0, input=tcp.0 > output=websocket.0
-[2020/07/07 03:40:17] [ info] [out_ws] handshake for ws
-[2020/07/07 03:40:17] [ info] [engine] flush chunk '12734-1594107609.72852130.flb' succeeded at retry 1: task_id=1, input=tcp.0 > output=websocket.0
+[2021/02/05 22:17:09] [ info] [engine] started (pid=6056)
+[2021/02/05 22:17:09] [ info] [storage] version=1.1.0, initializing...
+[2021/02/05 22:17:09] [ info] [storage] in-memory
+[2021/02/05 22:17:09] [ info] [storage] normal synchronization mode, checksum disabled, max_chunks_up=128
+[2021/02/05 22:17:09] [ info] [input:tcp:tcp.0] listening on 0.0.0.0:5170
+[2021/02/05 22:17:09] [ info] [out_ws] we have following parameter /, 127.0.0.1, 8080, 25
+[2021/02/05 22:17:09] [ info] [output:websocket:websocket.0] worker #1 started
+[2021/02/05 22:17:09] [ info] [output:websocket:websocket.0] worker #0 started
+[2021/02/05 22:17:09] [ info] [sp] stream processor started
+[2021/02/05 22:17:09] [ info] [output:websocket:websocket.0] worker #3 started
+[2021/02/05 22:17:09] [ info] [output:websocket:websocket.0] worker #2 started
+[2021/02/05 22:17:33] [ info] [out_ws] handshake for ws
+[2021/02/05 22:18:08] [ warn] [engine] failed to flush chunk '6056-1612534687.673438119.flb', retry in 7 seconds: task_id=0, input=tcp.0 > output=websocket.0 (out_id=0)
+[2021/02/05 22:18:15] [ info] [out_ws] handshake for ws
+^C[2021/02/05 22:18:23] [engine] caught signal (SIGINT)
+[2021/02/05 22:18:23] [ warn] [engine] service will stop in 5 seconds
+[2021/02/05 22:18:27] [ info] [engine] service stopped
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #0 stopping...
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #0 stopped
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #1 stopping...
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #1 stopped
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #2 stopping...
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #2 stopped
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #3 stopping...
+[2021/02/05 22:18:27] [ info] [output:websocket:websocket.0] thread worker #3 stopped
+[2021/02/05 22:18:27] [ info] [out_ws] flb_ws_conf_destroy
 ```
 
 ### Scenario Description
 
-From the output of fluent-bit log, we see that once data has been ingested into fluent bit, plugin would perform handshake. After a while, no data or traffic is undergoing, tcp connection has been abort. And then another piece of data arrived, a try fro websocket plugin has been triggered, following with another handshake and data flush.
+From the output of fluent-bit log, we see that once data has been ingested into fluent bit, plugin would perform handshake. After a while, no data or traffic is undergoing, tcp connection would been abort. And then another piece of data arrived, a retry for websocket plugin has been triggered, with another handshake and data flush.