Send logs from HTTP to Loki

A simple guide to send logs from HTTP to Loki in just a few minutes.
type: tutorialdomain: sourcesdomain: sinkssource: httpsink: loki

Logs are an essential part of observing any service; without them you are flying blind. But collecting and analyzing them can be a real challenge -- especially at scale. Not only do you need to solve the basic task of collecting your logs, but you must do it in a reliable, performant, and robust manner. Nothing is more frustrating than having your logs pipeline fall on it's face during an outage, or even worse, disrupt more important services!

Fear not! In this guide we'll show you how to send send logs from HTTP to Loki and build a logs pipeline that will be the backbone of your observability strategy.

Background

What is Loki?

Loki is a horizontally-scalable, highly-available, multi-tenant log aggregation system inspired by Prometheus. It is designed to be very cost effective and easy to operate. It does not index the contents of the logs, but rather a set of labels for each log stream.

Strategy

How This Guide Works

We'll be using Vector to accomplish this task. Vector is a popular open-source utility for building observability pipelines. It's written in Rust, making it lightweight, ultra-fast and highly reliable. And we'll be deploying Vector as a service.

The service deployment strategy treats Vector like a separate service. It is designed to receive data from an upstream source and fan-out to one or more destinations. For this guide, Vector will receive data from HTTP via Vector's http source. The following diagram demonstrates how it works.

Vector Service Deployment StrategyVector service deployment strategy
1. Vector receives data from HTTP
Vector will accept log data over HTTP.
2. Vector processes data
Vector parses, transforms, and enriches data.
3. Vector transmits data to Loki
Vector will send structured logs to the Loki logging service.

What We'll Accomplish

To be clear, here's everything we'll accomplish in this short guide:

  • Accept log data over HTTP.
    • Decode JSON, NDJSON, and text.
    • Enrich your logs with select HTTP headers.
  • Send structured logs to the Loki logging service.
    • Batch data to maximize throughput.
    • Set custom labels to be added to all log data.
    • Automatically retry failed requests, with backoff.
    • Buffer your data in-memory or on-disk for performance and durability.
  • All in just a few minutes!

Tutorial

  1. Install Vector

    curl --proto '=https' --tlsv1.2 -sSf https://sh.vector.dev | sh
    explain this command

    Or choose your preferred method.

  2. Configure Vector

    cat <<-VECTORCFG > vector.toml
    [sources.in]
    address = "0.0.0.0:80" # required
    type = "http" # required
    [sinks.out]
    # General
    endpoint = "http://localhost:3100" # required
    inputs = ["in"] # required
    type = "loki" # required
    # Labels
    labels.key = "value" # example
    labels.key = "{{ event_field }}" # example
    VECTORCFG
    explain this command
  3. Start Vector

    vector --config vector.toml

    That's it! Simple and to the point. Hit ctrl+c to exit.

Next Steps

Vector is powerful utility and we're just scratching the surface in this guide. Here are a few pages we recommend that demonstrate the power and flexibility of Vector:

Vector Github repo 4k
Vector is free and open-source!
Vector getting started series
Go from zero to production in under 10 minutes!
Vector documentation
Thoughtful, detailed docs that respect your time.