Crate tracing_ndjson

source ·
Expand description

tracing-ndjson

Rust

A simple library for tracing in new-line delimited JSON format. This library is meant to be used with tracing as an alternative to the tracing_subscriber::fmt::json formatter.

The goal of this crate is to provide a flattend JSON event, comprising of fields from the span attributes and event fields, with customizeable field names and timestamp formats.

Features

  • Configurable field names for target, message, level, and timestamp.
  • Configurable timestamp formats
    • RFC3339 (2023-10-08T03:30:52Z),
    • RFC339Nanos (2023-10-08T03:30:52.123456789Z)
    • Unix timestamp (1672535452)
    • UnixMills (1672535452123)
  • Captures all span attributes and event fields in the root of the JSON object. Collisions will result in overwriting the existing field.

Limitations

  • When flattening span attributes and event fields, the library will overwrite any existing fields with the same name, including the built-in fields such as target, message, level, timestamp, file, and line.
  • Non-determistic ordering of fields in the JSON object. (JSON objects are unordered)
  • Currently only logs to stdout. (PRs welcome!)

Usage

Add this to your Cargo.toml:

[dependencies]
tracing = "0.1"
tracing-ndjson = "0.2"

use tracing_subscriber::prelude::*;

let subscriber = tracing_subscriber::registry().with(tracing_ndjson::layer());

tracing::subscriber::set_global_default(subscriber).unwrap();

tracing::info!(life = 42, "Hello, world!");
// {"level":"info","target":"default","life":42,"timestamp":"2023-10-20T21:17:49Z","message":"Hello, world!"}

let span = tracing::info_span!("hello", "request.uri" = "https://example.com");
span.in_scope(|| {
    tracing::info!("Hello, world!");
    // {"message":"Hello, world!","request.uri":"https://example.com","level":"info","target":"default","timestamp":"2023-10-20T21:17:49Z"}
});

Examples

See the examples directory for more examples.

License

Licensed under MIT license

Structs

  • Builder
    A builder for the JSON formatter. This is used to configure the JSON formatter. The default configuration is:
  • JsonFormattingLayer

Enums

  • Casing
  • TimestampFormat
    A timestamp format for the JSON formatter. This is used to format the timestamp field in the JSON output. The default is RFC3339.

Functions

  • builder
    Alias for Builder::default(). This is used to configure the JSON formatter.
  • layer
    Returns a Layer that subscribes to all spans and events using a JSON formatter. This is used to configure the JSON formatter.