簡介 Fluentd 寫入 InfluxDB 透過 Fluent::Plugin::InfluxDB

 此文件用來說明 使用 fluent client-go API 並且 寫入資料到InfluxDB 透過 Fluentd 的Plugin Fluent::Plugin::InfluxDB (InfluxDB是用2.0)

fluent-logger-golang (fluent client-go API)

參考 URL: A structured event logger for Fluentd (Golang)

目前使用此fluent client-go API，將資料傳入Fluentd, 

會使用其Async模式來避免後續的latency event被block住, 當Fluentd server有問題時:

// Use "Async" to enable asynchronous I/O (connect and write)
// for sending events to Fluentd without blocking
setting.FluentdLogger.Logger, errF = fluent.New(
    fluent.Config{Async: true, FluentHost: fluenthost, FluentPort: intFluentPort})
if errF != nil {
		fmt.Println("[ERROR]:", errF)
		setting.FluentdLogger.Enabled = false
}

P.S: When Fluentd server has a problem, the events which are going to send will be buffered on the memory. The default size is 8192

BufferLimit  

Sets the number of events buffered on the memory.

The example of using fluent-logger-golang to send data:

tag := "apm.latency"
var data = map[string]string{
		"mytimestamp": strconv.FormatInt(time.Now().Unix(), 10),
		"mydata":      "hoge",
		"myjob":       "apm",
		"myvalue":     "55.55",
}
error := logger.Post(tag, data)Fluentd

Fluentd

Fluentd安裝，請參考官網
https://docs.fluentd.org/installation/install-by-deb

Fluentd操作

# 啟動/關閉/查看服務
sudo systemctl start td-agent.service
sudo systemctl stop td-agent.service
sudo systemctl status td-agent.service
sudo systemctl restart td-agent.service

#修改Fluentd設定
vi /etc/td-agent/td-agent.conf
#查看Fluentd logs
cat /var/log/td-agent/td-agent.log

InfluxDB 2.X

2.0 以上的InfluxDB 會需要token，Client端才有權限讀寫，其中一種方式查出Token是用InfluxDB自己的Web http://<your ip address>:8086，登入後點選"Data"

例如:

選擇GO

可以看到 token的值

// You can generate a Token from the "Tokens Tab" in the UI const token = "Iiq0TiIpL9lXn2GATwh3WeZBkLq-SEul6C0yrKLjq4T4WZ9b0BKVAsFeNs8q0Is93SMbhF0l63s4DwJja4MSbw=="

Fluent::Plugin::InfluxDB (This plugin is for using with InfluxDB 2.x 目前使用此Plugin)

This repository contains the reference Fluentd plugin for the InfluxDB 2.0.

Fluentd需要此Plugin來對應寫資料到InfluxDB2

我目前用的: The configuration of /etc/td-agent/td-agent.conf

#<match apm.**>
#  @type stdout
#</match>

<match apm.**>
    @type copy
    <store>
      @type influxdb2

      url             <https://localhost:8086>
      token           Iiq0TiIpL9lXn2GATwh3WeZBkLq-SEul6C0yrKLjq4TXXXX
      use_ssl         false
      bucket          apm
      org             com
      time_precision  s
      tag_keys          ["mytimestamp","mydata"]
      field_keys        ["myvalue"]
    </store>
    <store>
      @type stdout
    </store>
</match>

The result in InfluxDB

安裝此plugin:

sudo td-agent-gem install fluent-plugin-influxdb-v2
sudo td-agent-gem uninstall fluent-plugin-influxdb-v2

influxdb-plugin-fluent (只適用於InfluxDB 1.x instances)

fluent-plugin-influxdb is a buffered output plugin for fluentd and influxDB.

Configuration Example

<match apm.**>
  @type influxdb
  host  localhost
  port  8086
  dbname apm
  user  danny
  password  xxxxxxxxx
  use_ssl false
  time_precision s
  tag_keys ["timestamp", "data"]
  sequence_tag _seq
</match>

安裝 plugin:

sudo td-agent-gem install fluent-plugin-influxdb
sudo td-agent-gem uninstall fluent-plugin-influxdb

Reference

遇過的Error Message

[warn]: #0 failed to flush the buffer. retry_time=7 next_retry_seconds=2021-04-22 14:28:33 14429497340994114529/137438953472000000000 +0800 chunk="5c089be4bdfb9a28fb4b5ac58228a90 7" error_class=InfluxDB2::InfluxError error="failure writing points to database: partial write: points beyond retention policy dropped=1" 2021-04-22 14:27:22 +0800 [warn]: #0 suppressed same stacktrace

https://stackoverflow.com/questions/54359348/unable-to-insert-data-in-influxdb