Datadog Formatting Layer

A crate providing a tracing-subscriber layer for formatting events so Datadog can parse them.

Features

• Provides a layer for tracing-subscriber
• Generates parsable "logs" for datadog and prints them to stdout
• Enables log correlation between spans and "logs" (see datadog docs)

Why not just tracing_subscriber::fmt().json() ?

The problem is, that datadog expects the "logs" to be in a specific (mostly undocumented) json format.

This crates tries to mimic this format.

Usage

Simple

```rust use datadogformattinglayer::DatadogFormattingLayer; use tracing::info; use tracing_subscriber::prelude::*;

tracing_subscriber::registry() .with(DatadogFormattingLayer) .init();

info!(user = "Jack", "Hello World!"); ```

Running this code will result in the following output on stdout:

json { "timestamp": "2023-06-21T10:36:50.364874878+00:00", "level": "INFO", "message": "Hello World user=Jack", "target": "simple" }

With Opentelemetry

```rust use datadogformattinglayer::DatadogFormattingLayer; use opentelemetry::{ global, sdk::{ propagation::TraceContextPropagator, trace::{RandomIdGenerator, Sampler}, }, }; use opentelemetrydatadog::ApiVersion; use tracing::{debug, error, info, instrument, warn}; use tracingsubscriber::{prelude::*, util::SubscriberInitExt};

// Just some otel boilerplate global::settextmap_propagator(TraceContextPropagator::new());

let tracer = opentelemetrydatadog::newpipeline() .withservicename("my-service") .withtraceconfig( opentelemetry::sdk::trace::config() .withsampler(Sampler::AlwaysOn) .withidgenerator(RandomIdGenerator::default()), ) .withapiversion(ApiVersion::Version05) .withenv("rls") .withversion("420") .installsimple() .unwrap();

// Use both the tracer and the formatting layer tracingsubscriber::registry() .with(DatadogFormattingLayer) .with(tracingopentelemetry::layer().with_tracer(tracer)) .init();

// Here no span exists info!(user = "Jack", "Hello World!"); some_test("fasel");

// This will create a span and a trace id which is attached to the "logs"

[instrument(fields(hello = "world"))]

fn some_test(value: &str) { // Here some span exists info!(ola = "salve", value, "Bla {value}"); } ```

When running this code with an datadog agent installed the logs will be sent to datadog and parsed there.

Otherwise the following output will be printed to stdout

json {"timestamp":"2023-06-21T10:36:50.363224217+00:00","level":"INFO","message":"Hello World! user=Jack","target":"otel"} {"timestamp":"2023-06-21T10:36:50.363384118+00:00","level":"INFO","message":"Bla fasel user=Jack ola=salve value=Fasel hello=world","target":"otel","dd.trace_id":0,"dd.span_id":10201226522570980512}