use std::collections::BTreeMap;
use std::sync::atomic::{AtomicU64, Ordering};
use crate::context::{set_trace_context_internal, trace_snapshot, ContextGuard};
pub struct NoopSpan {
trace_id: String,
span_id: String,
guard: Option<ContextGuard>,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct Tracer {
name: String,
}
pub static tracer: std::sync::LazyLock<Tracer> = std::sync::LazyLock::new(|| Tracer::new(None));
impl Tracer {
pub fn new(name: Option<&str>) -> Self {
Self {
name: name.unwrap_or("provide.telemetry").to_string(),
}
}
pub fn name(&self) -> &str {
&self.name
}
pub fn start_span(&self, _name: &str) -> NoopSpan {
let trace_id = next_hex(32);
let span_id = next_hex(16);
let guard = set_trace_context(Some(trace_id.clone()), Some(span_id.clone()));
NoopSpan {
trace_id,
span_id,
guard: Some(guard),
}
}
}
static TRACE_COUNTER: AtomicU64 = AtomicU64::new(1);
fn next_hex(len: usize) -> String {
let seed = TRACE_COUNTER.fetch_add(1, Ordering::Relaxed);
let mut value = format!("{seed:016x}");
while value.len() < len {
let snapshot = TRACE_COUNTER.fetch_add(1, Ordering::Relaxed);
value.push_str(&format!("{snapshot:016x}"));
}
value[..len].to_string()
}
pub fn get_tracer(name: Option<&str>) -> Tracer {
Tracer::new(name)
}
pub fn set_trace_context(trace_id: Option<String>, span_id: Option<String>) -> ContextGuard {
set_trace_context_internal(trace_id, span_id)
}
pub fn get_trace_context() -> BTreeMap<String, Option<String>> {
let snapshot = trace_snapshot();
BTreeMap::from([
("trace_id".to_string(), snapshot.trace_id),
("span_id".to_string(), snapshot.span_id),
])
}
pub fn trace<T, F>(name: &str, callback: F) -> T
where
F: FnOnce() -> T,
{
let _span = tracer.start_span(name);
callback()
}
impl NoopSpan {
pub fn trace_id(&self) -> &str {
&self.trace_id
}
pub fn span_id(&self) -> &str {
&self.span_id
}
pub fn set_attribute(&self, _key: &str, _value: &str) {}
pub fn record_error(&self, _error: &str) {}
}
impl Drop for NoopSpan {
fn drop(&mut self) {
drop(self.guard.take());
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn tracer_test_tracer_names_match_contract() {
assert_eq!(tracer.name(), "provide.telemetry");
assert_eq!(get_tracer(Some("custom.tracer")).name(), "custom.tracer");
}
#[test]
fn tracer_test_next_hex_respects_requested_length_and_advances() {
let first = next_hex(16);
let second = next_hex(16);
let long = next_hex(32);
assert_eq!(first.len(), 16);
assert_eq!(second.len(), 16);
assert_eq!(long.len(), 32);
assert_ne!(first, second);
assert!(first.chars().all(|ch| ch.is_ascii_hexdigit()));
assert!(long.chars().all(|ch| ch.is_ascii_hexdigit()));
}
}