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#![warn(missing_docs)]
//! # Structured Contextual Logging (or tracing)
//! ## Why
//! [Watch](https://www.youtube.com/watch?v=JjItsfqFIdo) or [Read](https://tokio.rs/blog/2019-08-tracing/)
//!
//! ## Intention of this crate
//! This crate is designed ot be a place to experiment with ideas around
//! tracing and structured logging. This crate will probably never stabilize.
//! Instead it is my hope to feed any good ideas back into the underlying
//! dependencies.
//!
//! ## Usage
//! There are a couple of ways to use structured logging.
//! ### Console and filter
//! If you want to try and filter in on an issue it might be easiest to simply log to the console and filter on what you want.
//! Here's an example command:
//! ```bash
//! RUST_LOG='core[a{something="foo"}]=debug' my_bin
//! ```
//! Or a more simple version using the default `Log`:
//! ```bash
//! RUST_LOG=trace my_bin
//! ```
//! #### Types of tracing
//! There are many types of tracing exposed by this crate.
//! The [Output] type is designed to be used with something like [structopt](https://docs.rs/structopt/0.3.20/structopt/)
//! so you can easily set which type you want with a command line arg.
//! You could also use an environment variable.
//! The [Output] variant is passing into the [init_fmt] function on start up.
//! #### Filtering
//! ```bash
//! RUST_LOG='core[a{something="foo"}]=debug'
//! ```
//! Here we are saying show me all the events that are:
//! - In the `core` module
//! - Inside a span called `a`
//! - The span `a` has to have a field called `something` that is equal to `foo`
//! - They are at least debug level.
//!
//! Most of these options are optional.
//! They can be combined like:
//! ```bash
//! RUST_LOG='[{}]=error,[{something}]=debug'
//! ```
//! > The above means show me errors from anywhere but also any event or span with the field something that's at least debug.
//!
//! [See here](https://docs.rs/tracing-subscriber/0.2.2/tracing_subscriber/filter/struct.EnvFilter.html) for more info.
//!
//! #### Json
//! Sometimes there's too much data and it's better to capture it to interact with using another tool later.
//! For this we can output everything as Json using the flag `--structured Json`.
//! Then you can pipe the output from stdout to you're file of choice.
//! Here's some sample output:
//! ```json
//! {"time":"2020-03-03T08:07:05.910Z","name":"event crates/sim2h/src/sim2h_im_state.rs:695","level":"INFO","target":"sim2h::sim2h_im_state","module_path":"sim2h::sim2h_im_state","file":"crates/sim2h/src/sim2h_im_stat
//! e.rs","line":695,"fields":{"space_hashes":"[]"},"spans":[{"id":[1099511627778],"name":"check_gossip","level":"INFO","target":"sim2h::sim2h_im_state","module_path":"sim2h::sim2h_im_state","file":"crates/sim2h/src/s
//! im2h_im_state.rs","line":690}]}
//! ```
//! Every log will include the above information expect for the spans which will only show up if there are parent spans in the context of the event.
//!
//! You can combine filter with Json as well.
//!
//! ##### Tools
//! Some useful tools for formatting and using the json data.
//! - [json2csv](https://www.npmjs.com/package/json2csv)
//! - [jq](https://stedolan.github.io/jq/)
//! - [tad](https://www.tadviewer.com/)
//!
//! A sample workflow:
//! ```bash
//! RUST_LOG='core[{}]=debug' my_bin --structured Json > log.json
//! cat out.json | jq '. | {time: .time, name: .name, message: .fields.message, file: .file, line: .line, fields: .fields, spans: .spans}' | json2csv -o log.csv
//! tad log.csv
//! ```
use tracing::Subscriber;
use tracing_subscriber::{
filter::EnvFilter,
fmt::{
format::{DefaultFields, FmtSpan, Format},
time::UtcTime,
},
layer::SubscriberExt,
registry::LookupSpan,
util::SubscriberInitExt,
Layer, Registry,
};
use derive_more::Display;
use std::str::FromStr;
use std::sync::{Arc, Mutex};
use flames::FlameTimed;
use fmt::*;
mod flames;
mod fmt;
pub mod metrics;
mod writer;
mod open;
#[cfg(all(feature = "opentelemetry-on", feature = "channels"))]
pub use open::channel;
#[cfg(feature = "opentelemetry-on")]
pub use open::should_run;
pub use open::{Config, Context, MsgWrap, OpenSpanExt};
use crate::flames::{toml_path, FlameTimedConsole};
use crate::writer::InMemoryWriter;
pub use tracing;
use tracing_subscriber::fmt::MakeWriter;
#[derive(Debug, Clone, Display)]
/// Sets the kind of structured logging output you want
pub enum Output {
/// More compact version of above
Compact,
/// Outputs everything as json
Json,
/// Json with timed spans
JsonTimed,
/// Regular logging (default)
Log,
/// Regular logging plus timed spans
LogTimed,
/// Creates a flamegraph from timed spans
FlameTimed,
/// Creates a flamegraph from timed spans using idle time
IceTimed,
/// Opentelemetry tracing
OpenTel,
/// No logging to console
None,
}
/// ParseError is a String
pub type ParseError = String;
impl FromStr for Output {
type Err = ParseError;
fn from_str(day: &str) -> Result<Self, Self::Err> {
match day {
"Json" => Ok(Output::Json),
"JsonTimed" => Ok(Output::JsonTimed),
"IceTimed" => Ok(Output::IceTimed),
"Log" => Ok(Output::Log),
"LogTimed" => Ok(Output::LogTimed),
"FlameTimed" => Ok(Output::FlameTimed),
"Compact" => Ok(Output::Compact),
// "OpenTel" => Ok(Output::OpenTel),
"None" => Ok(Output::None),
_ => Err("Could not parse log output type".into()),
}
}
}
/// Run logging in a unit test.
///
/// RUST_LOG must be set or this is a no-op.
pub fn test_run() {
if std::env::var_os("RUST_LOG").is_none() {
return;
}
static INIT_ONCE: std::sync::Once = std::sync::Once::new();
INIT_ONCE.call_once(|| {
init_fmt(Output::Log).unwrap();
});
}
/// Run tracing in a test that uses open telemetry to
/// send span contexts across process and thread boundaries.
pub fn test_run_open() -> Result<(), errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(());
}
init_fmt(Output::OpenTel)
}
/// Same as test_run but with timed spans
pub fn test_run_timed() -> Result<(), errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(());
}
init_fmt(Output::LogTimed)
}
/// Same as test_run_timed but saves as json
pub fn test_run_timed_json() -> Result<(), errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(());
}
init_fmt(Output::JsonTimed)
}
/// Generate a flamegraph from timed spans of "busy time".
pub fn test_run_timed_flame() -> Result<Option<Box<impl Drop>>, errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(None);
}
let buffer = Arc::new(Mutex::new(Vec::new()));
let writer_handle = InMemoryWriter::new(buffer.clone());
init_fmt_with_opts(Output::FlameTimed, move || {
InMemoryWriter::new(buffer.clone())
})?;
Ok(Some(Box::new(FlameTimed::new(writer_handle))))
}
/// Generate a flamegraph from timed spans "busy time".
/// Takes a path where you are piping the output into.
/// If the path is provided a flamegraph will automatically be generated.
/// TODO: Get auto inferno to work
/// for now use (fish, or the bash equiv):
/// `2>| inferno-flamegraph > flamegraph_test_ice_(date +'%d-%m-%y-%X').svg`
/// And run with `cargo test --quiet`
#[deprecated]
pub fn test_run_timed_flame_console(
path: Option<&str>,
) -> Result<Option<impl Drop>, errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(None);
}
init_fmt(Output::FlameTimed)?;
Ok(path.and_then(|p| {
toml_path().map(|mut t| {
t.push(p);
FlameTimedConsole::new(t)
})
}))
}
/// Generate a flamegraph from timed spans of "idle time".
pub fn test_run_timed_ice() -> Result<Option<Box<impl Drop>>, errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(None);
}
let buffer = Arc::new(Mutex::new(Vec::new()));
let writer_handle = InMemoryWriter::new(buffer.clone());
init_fmt_with_opts(Output::IceTimed, move || {
InMemoryWriter::new(buffer.clone())
})?;
Ok(Some(Box::new(FlameTimed::new(writer_handle))))
}
/// Generate a flamegraph from timed spans "idle time".
/// Takes a path where you are piping the output into.
/// If the path is provided a flamegraph will automatically be generated.
/// TODO: Get auto inferno to work
/// for now use (fish, or the bash equiv):
/// `2>| inferno-flamegraph -c blue > flamegraph_test_ice_(date +'%d-%m-%y-%X').svg`
/// And run with `cargo test --quiet`
#[deprecated]
pub fn test_run_timed_ice_console(
path: Option<&str>,
) -> Result<Option<impl Drop>, errors::TracingError> {
if std::env::var_os("RUST_LOG").is_none() {
return Ok(None);
}
init_fmt(Output::IceTimed)?;
Ok(path.and_then(|p| {
toml_path().map(|mut t| {
t.push(p);
FlameTimedConsole::new(t)
})
}))
}
/// Build the canonical filter based on env
pub fn standard_filter() -> Result<EnvFilter, errors::TracingError> {
let mut filter = match std::env::var("RUST_LOG") {
Ok(_) => EnvFilter::from_default_env().add_directive("[{aitia}]=debug".parse()?),
Err(_) => EnvFilter::from_default_env()
.add_directive("[wasm_debug]=debug".parse()?)
.add_directive("[{aitia}]=off".parse()?),
};
if std::env::var("CUSTOM_FILTER").is_ok() {
EnvFilter::try_from_env("CUSTOM_FILTER")
.map_err(|e| eprintln!("Failed to parse CUSTOM_FILTER {:?}", e))
.map(|f| {
filter = f;
})
.ok();
}
Ok(filter)
}
/// Return a subscriber builder directly, for times when you need more control over the
/// produced subscriber
pub fn standard_layer_unfiltered<W, S>(
writer: W,
) -> Result<tracing_subscriber::fmt::Layer<S, DefaultFields, Format, W>, errors::TracingError>
where
W: for<'w> MakeWriter<'w> + Send + Sync + 'static,
S: Subscriber + Send + Sync + for<'span> LookupSpan<'span>,
{
Ok(tracing_subscriber::fmt::Layer::default()
.with_test_writer()
.with_writer(writer)
.with_file(true)
.with_line_number(true)
.with_target(true))
}
/// Return a subscriber builder directly, for times when you need more control over the
/// produced subscriber
pub fn standard_layer<W, S>(writer: W) -> Result<impl Layer<S>, errors::TracingError>
where
W: for<'w> MakeWriter<'w> + Send + Sync + 'static,
S: Subscriber + Send + Sync + for<'span> LookupSpan<'span>,
{
let filter = standard_filter()?;
Ok(standard_layer_unfiltered(writer)?.with_filter(filter))
}
/// This checks RUST_LOG for a filter but doesn't complain if there is none or it doesn't parse.
/// It then checks for CUSTOM_FILTER which if set will output an error if it doesn't parse.
pub fn init_fmt(output: Output) -> Result<(), errors::TracingError> {
init_fmt_with_opts(output, std::io::stderr)
}
fn init_fmt_with_opts<W>(output: Output, writer: W) -> Result<(), errors::TracingError>
where
W: for<'writer> MakeWriter<'writer> + Send + Sync + 'static,
{
let filter = standard_filter()?;
println!("Initialising formatting with args {:?}", output);
match output {
Output::Json => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.with_timer(UtcTime::rfc_3339())
.json()
.event_format(FormatEvent)
.with_filter(filter),
)
.init(),
Output::JsonTimed => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.with_span_events(FmtSpan::CLOSE)
.with_timer(UtcTime::rfc_3339())
.json()
.event_format(FormatEvent)
.with_filter(filter),
)
.init(),
Output::Log => Registry::default().with(standard_layer(writer)?).init(),
Output::LogTimed => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.with_span_events(FmtSpan::FULL)
.with_filter(filter),
)
.init(),
Output::FlameTimed => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.with_span_events(FmtSpan::CLOSE)
.with_timer(UtcTime::rfc_3339())
.event_format(FormatEventFlame)
.with_filter(filter),
)
.init(),
Output::IceTimed => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.with_span_events(FmtSpan::CLOSE)
.with_timer(UtcTime::rfc_3339())
.event_format(FormatEventIce)
.with_filter(filter),
)
.init(),
Output::Compact => Registry::default()
.with(
standard_layer_unfiltered(writer)?
.compact()
.with_filter(filter),
)
.init(),
Output::OpenTel => {
#[cfg(feature = "opentelemetry-on")]
{
use open::OPEN_ON;
use opentelemetry::api::Provider;
OPEN_ON.store(true, std::sync::atomic::Ordering::SeqCst);
use tracing_subscriber::prelude::*;
open::init();
let tracer = opentelemetry::sdk::Provider::default().get_tracer("component_name");
let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
finish(
Registry::default()
.with(standard_layer(writer)?)
.with(telemetry)
.with(open::OpenLayer)
.init(),
)
}
#[cfg(not(feature = "opentelemetry-on"))]
{
init_fmt_with_opts(Output::Log, writer)?
}
}
Output::None => (),
};
Ok(())
}
pub mod errors {
//! Error in the tracing/logging framework
use thiserror::Error;
/// Error in the tracing/logging framework
#[allow(missing_docs)] // should be self-explanatory
#[derive(Error, Debug)]
pub enum TracingError {
#[error(transparent)]
SetGlobal(#[from] tracing::subscriber::SetGlobalDefaultError),
#[error("Failed to setup tracing flame")]
TracingFlame,
#[error(transparent)]
BadDirective(#[from] tracing_subscriber::filter::ParseError),
}
}