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.
70 lines
2.2 KiB
Rust
70 lines
2.2 KiB
Rust
//! Tracing subscriber initialisation with JSON output.
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//!
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//! Uses `tracing_subscriber::fmt` with a custom `Make` impl that injects
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//! `instance_id` into every log line.
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use once_cell::sync::Lazy;
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use std::str::FromStr;
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use tracing_subscriber::{
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fmt::{self, format::FmtSpan},
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layer::SubscriberExt,
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util::SubscriberInitExt,
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EnvFilter,
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};
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/// Global instance identifier, resolved once at startup.
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/// Priority: `INSTANCE_ID` env var → system hostname → `"unknown"`.
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pub static INSTANCE_ID: Lazy<String> = Lazy::new(|| {
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std::env::var("INSTANCE_ID")
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.ok()
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.filter(|s| !s.is_empty())
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.or_else(|| {
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hostname::get()
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.ok()
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.and_then(|h| h.into_string().ok())
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.filter(|s| !s.is_empty())
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})
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.unwrap_or_else(|| "unknown".to_string())
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});
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/// Returns the platform-wide instance identifier for this process.
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pub fn instance_id() -> String {
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INSTANCE_ID.clone()
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}
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/// Initialises the global tracing subscriber with JSON-formatted output to stderr.
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///
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/// Each JSON line includes `ts`, `level`, `target` (module), `fields` (structured kv),
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/// `line`, `file`, and `instance_id`.
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/// `RUST_LOG` env var controls the log level filter.
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///
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/// Pass `defer = true` when OTLP will be initialized afterwards via `init_otlp()`;
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/// in that case this function only builds the subscriber without calling `try_init()`,
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/// and the combined (fmt + OTLP) subscriber is installed by `init_otlp()` instead.
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pub fn init_tracing_subscriber(level: &str, defer: bool) {
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let env_filter = EnvFilter::try_from_default_env()
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.or_else(|_| EnvFilter::from_str(level))
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.expect("invalid log level");
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let fmt_layer = 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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.with_span_events(FmtSpan::CLOSE)
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.flatten_event(true);
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let registry = tracing_subscriber::registry()
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.with(env_filter)
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.with(fmt_layer);
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if defer {
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// Caller will invoke init_otlp() which builds the full subscriber
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// including the OTLP layer, then calls try_init() once.
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return;
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}
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let _ = registry.try_init();
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}
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