Components and pipelines on Grafana Labs

What is a component

Fri, 14 Aug 2026 09:40:11 -0500

What is a component

You describe Alloy’s collect, transform, and send work with components.

In Alloy, a component is a building block that does one job. Components do the three jobs, collect, transform, and send, plus one more: finding the endpoints to collect from, called targets.

You connect components so that data flows through a pipeline that matches your needs. A pipeline is a chain of connected components that data passes through from source to destination.

Type and label

Each component has a type and a label. Take loki.write "local" as an example. loki.write is the type, and it tells you what kind of work the component does. "local" is the label, and it identifies this specific instance. Labels matter because you can run more than one loki.write component in a configuration, and you need a way to tell them apart.

The type and label combine to form the component’s identifier, loki.write.local. Use this identifier to reference the component’s exports elsewhere in your configuration.

A component label isn’t the same as a label attached to telemetry data, such as a Prometheus metric label. A component label identifies a piece of your configuration. A telemetry label is metadata that travels with the data itself as it moves through the pipeline.

A pipeline in action

Fri, 14 Aug 2026 09:40:11 -0500

A pipeline in action

Here is a small pipeline that collects logs from files and writes them to Loki, a Grafana backend for log storage. This example focuses on the shape of the pipeline, not the syntax details, which come later in this journey.

This configuration comes from the runnable logs-file example in the alloy-scenarios repository.

local.file_match "local_files" {
  path_targets = [{"__path__" = "/temp/logs/*.log", "job" = "python"}]
  sync_period  = "5s"
}

loki.source.file "log_scrape" {
  targets       = local.file_match.local_files.targets
  forward_to    = [loki.write.local.receiver]
  tail_from_end = true
}

loki.write "local" {
  endpoint {
    url = "http://loki:3100/loki/api/v1/push"
  }
}

Read it as discover, collect, send

This short path uses discovery to start collecting, then sends the data on. It skips the transform job. Processing components often sit between collect and send in fuller pipelines.

Follow the data from top to bottom, from discovering log files through to sending entries to Loki.

Discover: local.file_match finds matching log files.
Collect: loki.source.file tails those files and forwards the log entries.
Send: loki.write sends the entries to Loki.

Each component hands its work to the next, so the three components together form one pipeline.

Real pipelines do more

This example keeps the path short. Real production pipelines often add processing components between the collect and send steps to add or change identifying fields, parse log lines, filter unwanted data, or redact secrets.

Resources

Fri, 14 Aug 2026 09:40:11 -0500

Resources

Use these resources to learn more about components and how they form pipelines.

Documentation

Runnable examples

alloy-scenarios: self-contained runnable examples for logs, metrics, traces, and more