8defac98ad
Both init_tracing_subscriber() and init_otlp() were calling try_init() on the global tracing dispatcher, causing "global default trace dispatcher has already been set" at runtime when APP_OTEL_ENABLED=true. Fix: simplify the API so init_tracing_subscriber() never installs the subscriber — it either calls try_init() immediately (non-OTLP mode) or returns without installing (OTLP mode, defer=true). init_otlp() now builds the complete subscriber stack (registry + env_filter + fmt_layer + otel_layer) and calls try_init() once. init_tracing_subscriber() signature: (level, defer) → () init_otlp() signature: (endpoint, service_name, _, log_level) → Result The fmt layer is replicated inside init_otlp() for the OTLP path.
102 lines
3.3 KiB
Rust
102 lines
3.3 KiB
Rust
//! OTLP tracer initialisation (Phase 6).
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//!
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//! Uses HTTP/proto transport to the OTLP endpoint.
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//! The endpoint URL is passed as-is to the HTTP exporter.
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//! Default Kubernetes otel-collector-agent accepts HTTP on :4318.
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//!
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//! Call `init_otlp()` **after** `init_tracing_subscriber()` so the fmt layer is
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//! already registered. This function rebuilds the global subscriber with the
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//! OTLP tracing layer on top.
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use opentelemetry::trace::TracerProvider;
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use opentelemetry_otlp::{SpanExporter, WithExportConfig};
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use opentelemetry_sdk::trace as sdktrace;
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use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt, EnvFilter};
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/// Guard that shuts down the OTLP pipeline on drop.
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#[must_use]
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pub struct OtelGuard {
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provider: sdktrace::SdkTracerProvider,
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}
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impl OtelGuard {
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/// Force-flush any pending spans and shut down the OTLP exporter.
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pub async fn shutdown(self) {
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if let Err(e) = self.provider.shutdown() {
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tracing::warn!(error = %e, "OTLP tracer shutdown error");
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}
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}
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}
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/// Initialise OTLP tracing and attach it to the global tracing subscriber.
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///
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/// Uses HTTP/proto transport to the given endpoint.
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/// Returns `Ok(Some(guard))` on success; the caller should store the guard and
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/// call `guard.shutdown()` during app shutdown for a clean flush.
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///
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/// The `fmt_registry` parameter should be the value returned by
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/// `init_tracing_subscriber(level, true)` — i.e. a registry that was built but
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/// not yet installed. This function extends that registry with the OTLP tracing
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/// layer and calls `try_init()` once, avoiding the "global default already set" error.
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pub fn init_otlp(
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endpoint: &str,
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service_name: &str,
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_service_version: &str,
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log_level: &str,
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) -> Result<Option<OtelGuard>, InitOtlError> {
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if endpoint.is_empty() {
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return Err(InitOtlError::EmptyEndpoint);
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}
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let endpoint = endpoint.trim_end_matches('/');
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let exporter = SpanExporter::builder()
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.with_http()
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.with_endpoint(endpoint)
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.build()
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.map_err(|e| InitOtlError::ExporterInit(e.to_string()))?;
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let env_filter = EnvFilter::try_from_default_env()
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.unwrap_or_else(|_| EnvFilter::new(log_level));
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let fmt_layer = tracing_subscriber::fmt::layer()
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.json()
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.with_target(true)
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.with_thread_ids(false)
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.with_file(true)
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.with_line_number(true)
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.flatten_event(true);
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let tracer_provider = sdktrace::SdkTracerProvider::builder()
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.with_batch_exporter(exporter)
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.build();
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let tracer = tracer_provider.tracer(service_name.to_string());
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let otel_layer = tracing_opentelemetry::layer().with_tracer(tracer);
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let layered = tracing_subscriber::registry()
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.with(env_filter)
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.with(fmt_layer)
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.with(otel_layer);
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tracing::Dispatch::new(layered)
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.try_init()
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.map_err(|e| InitOtlError::SubscriberInit(e.to_string()))?;
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tracing::debug!(endpoint = %endpoint, "OTLP tracer installed");
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Ok(Some(OtelGuard { provider: tracer_provider }))
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}
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#[derive(Debug, thiserror::Error)]
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pub enum InitOtlError {
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#[error("endpoint is empty")]
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EmptyEndpoint,
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#[error("failed to build OTLP exporter: {0}")]
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ExporterInit(String),
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#[error("failed to set tracing subscriber: {0}")]
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SubscriberInit(String),
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}
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