How Telegraf works

Telegraf is a plugin-driven agent. A single Telegraf binary contains hundreds of plugins, and the plugins you enable in your configuration file determine what Telegraf collects, how it transforms that data, and where it writes it.

Plugin types

Four plugin types form the Telegraf data pipeline:

• Input plugins collect metrics from systems, services, databases, and sensors.
• Processor plugins transform, decorate, and filter metrics as they pass through the pipeline.
• Aggregator plugins produce new aggregate metrics, such as running means, minimums, and maximums, over configurable time windows.
• Output plugins write metrics to destinations such as InfluxDB, files, and message queues.

Two more plugin types extend how Telegraf runs:

• Secret store plugins keep credentials out of plain-text configuration files and resolve them at runtime. See secret store plugins.
• External plugins run outside the Telegraf binary, in any language, through the execd family of plugins. See external plugins.

Every plugin is configured in the same TOML configuration file, and you can enable multiple instances of the same plugin. For the complete list of available plugins, see the Plugin directory.

Polling and service inputs

Most input plugins poll: on each collection interval, Telegraf calls the plugin to gather current values, such as CPU usage or a database query result.

Service input plugins listen instead of polling. They run continuously, receiving data pushed to them from sources such as message queues (Kafka, MQTT, AMQP), socket listeners, and webhooks, and they emit metrics into the pipeline as data arrives.

Parsers and serializers

Many plugins move data in formats other than Telegraf metrics:

• Parsers convert raw input data, such as JSON, CSV, or Prometheus exposition format, into Telegraf metrics. Input plugins that support parsing accept a data_format option that selects one of the input data formats.
• Serializers convert Telegraf metrics into an output representation, such as InfluxDB line protocol, JSON, or Graphite. Output plugins that support serialization accept a data_format option that selects one of the output data formats.

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