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NATS Output Plugin

plugins/outputs/nats/README.md

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NATS Output Plugin

This plugin writes metrics to subjects of a set of NATS instances in one of the supported data formats.

⭐ Telegraf v1.1.0 🏷️ messaging 💻 all

Global configuration options <!-- @/docs/includes/plugin_config.md -->

Plugins support additional global and plugin configuration settings for tasks such as modifying metrics, tags, and fields, creating aliases, and configuring plugin ordering. See CONFIGURATION.md for more details.

Secret-store support

This plugin supports secrets from secret-stores for the username, password and credential option. See the secret-store documentation for more details on how to use them.

Configuration

toml
# Send telegraf measurements to NATS
[[outputs.nats]]
  ## URLs of NATS servers
  servers = ["nats://localhost:4222"]

  ## Optional client name
  # name = ""

  ## Optional credentials
  # username = ""
  # password = ""

  ## Optional NATS 2.0 and NATS NGS compatible user credentials
  # credentials = ""

  ## Optional authentication with nkey seed file (NATS 2.0)
  # nkey_seed = "/etc/telegraf/seed.txt"

  ## NATS subject for producer messages.
  ## This field can be a static string or a Go template, see README for details.
  ## Incompatible with `use_batch_format
  subject = "telegraf"

  ## Use Transport Layer Security
  # secure = false

  ## 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

  ## Use batch serialization instead of per metric. The batch format allows for the
  ## production of batch output formats and may more efficiently encode and write metrics.
  # use_batch_format = false

  ## Data format to output.
  ## 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_OUTPUT.md
  data_format = "influx"

  ## Jetstream specific configuration. If not nil, it will assume Jetstream context.
  ## Since this is a table, it should be present at the end of the plugin section. Else you can use inline table format.
  # [outputs.nats.jetstream]
    ## Name of the stream, required when using jetstream.
    # name = ""
    ## List of subjects to register on the stream
    # subjects = []

    ## Use asynchronous publishing for higher throughput, but note that it does not guarantee order within batches.
    # async_publish = false

    ## Timeout for wating on acknowledgement on asynchronous publishing
    ## String with valid units "ns", "us" (or "µs"), "ms", "s", "m", "h".
    # async_ack_timeout = "5s"

    ## Full jetstream create stream config, refer: https://docs.nats.io/nats-concepts/jetstream/streams
    # retention = "limits"
    # max_consumers = -1
    # max_msgs_per_subject = -1
    # max_msgs = -1
    # max_bytes = -1
    # max_age = 0
    # max_msg_size = -1
    # storage = "file"
    # discard = "old"
    # num_replicas = 1
    # duplicate_window = 120000000000
    # sealed = false
    # deny_delete = false
    # deny_purge = false
    # allow_rollup_hdrs = false
    # allow_direct = true
    # mirror_direct = false

    ## Disable creating the stream but assume the stream is managed externally
    ## and already exists. This will make the plugin fail if the steam does not exist.
    # disable_stream_creation = false

Subject Configuration

The subject setting determines where producer messages will be published in NATS. This can be a static subject (e.g., "telegraf"), or a dynamic subject template using Go’s text/template syntax.

Dynamic templates allow you to construct subjects based on properties of each metric, such as tags, name and fields. This enables fine-grained routing and filtering across NATS or JetStream subscribers.

This feature is incompatible with use_batch_format

Examples

Routing based on tags and metric name:

toml
subject = '{{ .Tag "region" }}.{{ .Tag "datacenter" }}.{{ .Tag "host" }}.{{ .Name }}'

Routing based on tags, metric name and field name:

toml
subject = 'telegraf.metrics.{{ .Tag "datacenter" }}.{{ .Tag "host" }}.{{ .Name }}.{{ .Field "Value1" }}'

If you’re using JetStream the value of subject determines where messages are published.

[!IMPORTANT] When using a dynamic subject template, Telegraf does not automatically register the generated subjects with the JetStream stream.

For dynamic subjects you must explicitly define matching subjects in outputs.nats.jetstream.subjects to ensure your stream can receive and retain those messages correctly.