MQTT 消费者 Telegraf 输入插件

MQTT 是一种机器对机器 (M2M)/物联网通信协议，设计为轻量级发布/订阅消息传递工具。MQTT 适用于需要小资源占用空间和/或网络带宽受限的连接。MQTT 由 IBM 的 Andy Stanford-Clark 博士和 Arcom 的 Arlen Nipper 于 1999 年创建。当时，IBM 正在与一家石油和天然气公司合作，该公司需要从偏远地区的石油管道中提取数据，这需要一种新的协议来满足这些要求。结果就是 MQTT。

MQTT 在 IBM 内部使用，直到他们在 2010 年发布了 MQTT 3.1 规范，允许其他人创建自己的 MQTT 实现。开发人员很快意识到 MQTT 对于物联网相关用例的价值，并且采用迅速增长，创建了许多开源代理和客户端库。2013 年，IBM 将 MQTT 提交给 OASIS 进行维护和标准化。

为什么使用 MQTT 消费者 Telegraf 输入插件？

Telegraf 使您可以轻松收集 MQTT 数据，而无需编写自定义脚本来连接到 MQTT 代理。Telegraf 还使处理和转换已传递的 MQTT 消息变得简单，然后再将其发送到数据库进行存储。将 Telegraf 与 MQTT 结合使用的另一个好处是 40 多个输出插件。这意味着您可以将 MQTT 数据发送到几乎任何数据存储，甚至同时发送到多个数据存储。

如何使用 MQTT 消费者 Telegraf 输入插件

MQTT 消费者 Telegraf 输入插件易于设置且可以快速运行。您只需配置 Telegraf YAML 配置文件即可。这是一个包含所有可用配置选项的基本示例

# Read metrics from MQTT topic(s)
[[inputs.mqtt_consumer]]
  ## Broker URLs for the MQTT server or cluster.  To connect to multiple
  ## clusters or standalone servers, use a separate plugin instance.
  ##   example: servers = ["tcp://:1883"]
  ##            servers = ["ssl://:1883"]
  ##            servers = ["ws://:1883"]
  servers = ["tcp://127.0.0.1:1883"]

  ## Topics that will be subscribed to.
  topics = [
    "telegraf/host01/cpu",
    "telegraf/+/mem",
    "sensors/#",
  ]

  ## The message topic will be stored in a tag specified by this value.  If set
  ## to the empty string no topic tag will be created.
  # topic_tag = "topic"

  ## QoS policy for messages
  ##   0 = at most once
  ##   1 = at least once
  ##   2 = exactly once
  ##
  ## When using a QoS of 1 or 2, you should enable persistent_session to allow
  ## resuming unacknowledged messages.
  # qos = 0

  ## Connection timeout for initial connection in seconds
  # connection_timeout = "30s"

  ## Maximum messages to read from the broker that have not been written by an
  ## output.  For best throughput set based on the number of metrics within
  ## each message and the size of the output's metric_batch_size.
  ##
  ## For example, if each message from the queue contains 10 metrics and the
  ## output metric_batch_size is 1000, setting this to 100 will ensure that a
  ## full batch is collected and the write is triggered immediately without
  ## waiting until the next flush_interval.
  # max_undelivered_messages = 1000

  ## Persistent session disables clearing of the client session on connection.
  ## In order for this option to work you must also set client_id to identify
  ## the client.  To receive messages that arrived while the client is offline,
  ## also set the qos option to 1 or 2 and don't forget to also set the QoS when
  ## publishing.
  # persistent_session = false

  ## If unset, a random client ID will be generated.
  # client_id = ""

  ## Username and password to connect MQTT server.
  # username = "telegraf"
  # password = "metricsmetricsmetricsmetrics"

  ## Optional TLS Config
  # tls_ca = "/etc/telegraf/ca.pem"
  # tls_cert = "/etc/telegraf/cert.pem"
  # tls_key = "/etc/telegraf/key.pem"
  ## Use TLS but skip chain & host verification
  # insecure_skip_verify = false

  ## Data format to consume.
  ## Each data format has its own unique set of configuration options, read
  ## more about them here:
  ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
  data_format = "influx"

  ## Enable extracting tag values from MQTT topics
  ## _ denotes an ignored entry in the topic path
  # [[inputs.mqtt_consumer.topic_parsing]]
  #   topic = ""
  #   measurement = ""
  #   tags = ""
  #   fields = ""
  ## Value supported is int, float, unit
  #   [[inputs.mqtt_consumer.topic.types]]
  #      key = type

示例输出

您的 MQTT 消息将被转换为如下所示的行协议

mqtt_consumer,host=pop-os,topic=telegraf/host01/cpu value=45i 1653579140440951943

mqtt_consumer,host=pop-os,topic=telegraf/host01/cpu value=100i 1653579153147395661

主题解析

默认情况下，您的 MQTT 消息将仅以 MQTT 主题作为标签值存储。如果要在其他字段上标记和查询，可以使用 Telegraf 解析 MQTT 消息并创建标签。这是一个例子

[[inputs.mqtt_consumer]]
  ## Broker URLs for the MQTT server or cluster.  To connect to multiple
  ## clusters or standalone servers, use a separate plugin instance.
  ##   example: servers = ["tcp://:1883"]
  ##            servers = ["ssl://:1883"]
  ##            servers = ["ws://:1883"]
  servers = ["tcp://127.0.0.1:1883"]

  ## Topics that will be subscribed to.
  topics = [
    "telegraf/+/cpu/23",
  ]

  ## Data format to consume.
  ## Each data format has its own unique set of configuration options, read
  ## more about them here:
  ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
  data_format = "value"
  data_type = "float"

  [[inputs.mqtt_consumer.topic_parsing]]
    topic = "telegraf/one/cpu/23"
    measurement = "_/_/measurement/_"
    tags = "tag/_/_/_"
    fields = "_/_/_/test"
    [inputs.mqtt_consumer.topic_parsing.types]
      test = "int"

使用 Telegraf 处理器插件

Telegraf 提供了许多处理器插件，可用于在将数据存储在 InfluxDB 中之前进一步转换数据。这是一个使用 Pivot 处理器插件将单个值指标转换为多个指标的示例

示例主题

/sensors/CLE/v1/device5/temp
/sensors/CLE/v1/device5/rpm
/sensors/CLE/v1/device5/ph
/sensors/CLE/v1/device5/spin

默认情况下，这将产生以下指标

sensors,site=CLE,version=v1,device_name=device5,field=temp value=390
sensors,site=CLE,version=v1,device_name=device5,field=rpm value=45.0
sensors,site=CLE,version=v1,device_name=device5,field=ph value=1.45

如果您将以下配置与 Pivot 处理器一起使用

[[inputs.mqtt_consumer]]
    ....
    topics = "/sensors/#"
    [[inputs.mqtt_consumer.topic_parsing]]
        measurement = "/measurement/_/_/_/_"
        tags = "/_/site/version/device_name/field"
[[processors.pivot]]
    tag_key = "field"
    value_key = "value"

输出将如下所示

sensors,site=CLE,version=v1,device_name=device5 temp=390,rpm=45.0,ph=1.45

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