Crate tracing_sprout

Tracing Sprout

A tokio-rs/tracing structured JSON formatting layer for the fledgling logger

This subscriber layer is derived from Tracing Bunyan Formatter, with a few tweaks to internals and some of the formatting (and rules surrounding it).

Features

• All traces will receive their parent's attributes as well as their own, child attributes will take precedence if there are collisions
• There is a very minimal timing capability that adds elapsed time to EVENT and EXIT traces
• TRACE, DEBUG and ERROR logs get slighly more metadata (file name, line number, module path & target) attached to them
• Avoids panics - as much as possible it opts to handle failure by eprintlning to stdout. These scenarios should be few and far between, but it's better that a failure in your tracing implementation doesn't poison your main application.

Example

use tracing::{subscriber::set_global_default, Subscriber};
use tracing_sprout::TrunkLayer;
use tracing_subscriber::prelude::*;
use tracing_subscriber::{EnvFilter, Registry};

let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"));
let formatting_layer = TrunkLayer::new("My Application".to_string(), std::io::stdout);
let subscriber = Registry::default()
     .with(env_filter)
     .with(formatting_layer);

set_global_default(subscriber).expect("failed to set up global tracing subscriber")

Developing on an application using this

Generally structured JSON logs are great for machines to read, but not so kind for humans. If you're developing an application that uses this layer it would be advisable to download some kind of CLI tool that outputs these logs in a slightly nicer format, a good example would be the node.js's pino-pretty, from there you can just pipe your logs into it for a nicer development experience

cargo run | pino-pretty

Log output and a more detailed example

See the examples for a basic demonstration of how this can be used. The basic.rs example in there would output logs like the following:

{"app_name":"I'm Groot","pid":2735,"id":"1","time":"Sat, 13 Feb 2021 14:16:15 +0000","timestamp":1613225775,"msg":"[EPIC MONTAGE | START]","level":"info","span.type":"enter"}
{"app_name":"I'm Groot","pid":2735,"id":"1","group":"[\"Peter Quill\", \"Gamora\", \"Drax\", \"Rocket\"]","time":"Sat, 13 Feb 2021 14:16:15 +0000","timestamp":1613225775,"msg":"[EVENT] Trying to plug in the power","level":"trace","file":"examples/basic.rs","line":32,"module":"basic","target":"basic","thread_id":"ThreadId(1)","thread_name":"main","span.type":"event"}
{"app_name":"I'm Groot","pid":2735,"id":"2","info":"I'm overwriting my parents ID","time":"Sat, 13 Feb 2021 14:16:15 +0000","timestamp":1613225775,"msg":"[MUSIC IS PLAYING | START]","level":"debug","file":"examples/basic.rs","line":34,"module":"basic","target":"basic","thread_id":"ThreadId(1)","thread_name":"main","span.type":"enter"}
...

However (excuse the verbosity here), by piping it through a tool like the one mentioned above (pino-pretty) you get the following output

[Sat, 13 Feb 2021 14:14:54 +0000] INFO (1331): [EPIC MONTAGE | START]
    app_name: "I'm Groot"
    id: "1"
    span.type: "enter"
[Sat, 13 Feb 2021 14:14:54 +0000] TRACE (1331): [EVENT] Trying to plug in the power
    app_name: "I'm Groot"
    id: "1"
    group: "[\"Peter Quill\", \"Gamora\", \"Drax\", \"Rocket\"]"
    file: "examples/basic.rs"
    line: 32
    module: "basic"
    target: "basic"
    thread_id: "ThreadId(1)"
    thread_name: "main"
    span.type: "event"
[Sat, 13 Feb 2021 14:14:54 +0000] DEBUG (1331): [MUSIC IS PLAYING | START]
    app_name: "I'm Groot"
    id: "2"
    info: "I'm overwriting my parents ID"
    file: "examples/basic.rs"
    line: 34
    module: "basic"
    target: "basic"
    thread_id: "ThreadId(1)"
    thread_name: "main"
    span.type: "enter"
    ...

Structs

TrunkLayer

The subscriber layer, add this to your application's tracing regisitry to initialize it