24 releases
0.3.9 | Aug 15, 2023 |
---|---|
0.3.8 | Jul 16, 2023 |
0.3.7 | Mar 31, 2023 |
0.3.4 | Oct 10, 2022 |
0.1.6 | May 12, 2020 |
#25 in Debugging
226,292 downloads per month
Used in 57 crates
(48 directly)
225KB
403 lines
tracing-bunyan-formatter
tracing-bunyan-formatter
provides two Layer
s implementation to be used on top of
a tracing
Subscriber
:
JsonStorageLayer
, to attach contextual information to spans for ease of consumption by downstreamLayer
s, viaJsonStorage
andSpan
'sextensions
;BunyanFormattingLayer
, which emits a bunyan-compatible formatted record upon entering a span, exiting a span and event creation.
Important: each span will inherit all fields and properties attached to its parent - this is
currently not the behaviour provided by tracing_subscriber::fmt::Layer
.
Example
use tracing_bunyan_formatter::{BunyanFormattingLayer, JsonStorageLayer};
use tracing::instrument;
use tracing::info;
use tracing_subscriber::Registry;
use tracing_subscriber::layer::SubscriberExt;
#[instrument]
pub fn a_unit_of_work(first_parameter: u64) {
for i in 0..2 {
a_sub_unit_of_work(i);
}
info!(excited = "true", "Tracing is quite cool!");
}
#[instrument]
pub fn a_sub_unit_of_work(sub_parameter: u64) {
info!("Events have the full context of their parent span!");
}
fn main() {
let formatting_layer = BunyanFormattingLayer::new("tracing_demo".into(), std::io::stdout);
let subscriber = Registry::default()
.with(JsonStorageLayer)
.with(formatting_layer);
tracing::subscriber::set_global_default(subscriber).unwrap();
info!("Orphan event without a parent span");
a_unit_of_work(2);
}
Console output
If you pipe the output in the bunyan
CLI:
As a pure-Rust alternative check out the bunyan
crate.
It includes a CLI binary with similar functionality to the original bunyan
CLI written in
JavaScript.
Implementation strategy
The layered approach we have pursued is not necessarily the most efficient,
but it makes it easier to separate different concerns and re-use common logic across multiple Layer
s.
While the current crate has no ambition to provide any sort of general purpose framework on top of
tracing-subscriber
's Layer
trait, the information collected by JsonStorageLayer
can be leveraged via
its public API by other downstream layers outside of this crate whose main concern is formatting.
It significantly lowers the amount of complexity you have to deal with if you are interested
in implementing your own formatter, for whatever reason or purpose.
You can also add another enrichment layer following the JsonStorageLayer
to collect
additional information about each span and store it in JsonStorage
.
We could have pursued this compositional approach to add elapsed_milliseconds
to each span
instead of baking it in JsonStorage
itself.
Optional features
You can enable the arbitrary_precision
feature to handle numbers of arbitrary size losslessly. Be aware of a known issue with untagged deserialization.
valuable
The tracing
crate has an unstable feature valuable
to enable
recording custom composite types like struct
s and enum
s. Custom
types must implement the valuable
crate's Valuable
trait, which
can be derived with a macro.
To use tracing
and tracing-bunyan-formatter
with valuable
, you must set the following configuration in your binary (as of the current crate versions on 2023-03-29):
-
Enable the feature flag
valuable
for thetracing
dependency. -
Add the
--cfg tracing_unstable
arguments to your rustc flags (seetracing
's documentation on this). This can be done in a few ways:-
Adding the arguments to your binary package's
.cargo/config.toml
underbuild.rustflags
. See thecargo
config reference documentation).Example:
[build] rustflags = "--cfg tracing_unstable"
-
Adding the arguments to the
RUSTFLAGS
environment variable when you runcargo
. See thecargo
environment variable docs).Example:
RUSTFLAGS="--cfg tracing_unstable" cargo build
-
-
Enable the feature flag
valuable
for thetracing-bunyan-formatter
dependency. -
Add dependency
valuable
. -
Optional: if you want to derive the
Valuable
trait for your custom types, enable the feature flagderive
for thevaluable
dependency.
See more details in the example in examples/valuable.rs
.
Testing
Just run cargo test
.
To run extra tests with the valuable
feature enabled, run:
RUSTFLAGS='--cfg tracing_unstable' \
cargo test --target-dir target/debug_valuable --features "valuable valuable/derive"
RUSTFLAGS='--cfg tracing_unstable' \
cargo run --example valuable --target-dir target/debug_valuable --features "valuable valuable/derive"
Dependencies
~3–4.5MB
~71K SLoC