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| 1 | +// Copyright (c) Zefchain Labs, Inc. |
| 2 | +// SPDX-License-Identifier: Apache-2.0 |
| 3 | + |
| 4 | +//! OpenTelemetry integration for tracing with OTLP export and Chrome trace export. |
| 5 | +
|
| 6 | +use tracing_chrome::ChromeLayerBuilder; |
| 7 | +use tracing_subscriber::{layer::SubscriberExt as _, util::SubscriberInitExt as _}; |
| 8 | +#[cfg(feature = "opentelemetry")] |
| 9 | +use { |
| 10 | + opentelemetry::{global, trace::TracerProvider}, |
| 11 | + opentelemetry_otlp::{SpanExporter, WithExportConfig}, |
| 12 | + opentelemetry_sdk::{ |
| 13 | + trace::{InMemorySpanExporter, SdkTracerProvider}, |
| 14 | + Resource, |
| 15 | + }, |
| 16 | + tracing_opentelemetry::OpenTelemetryLayer, |
| 17 | + tracing_subscriber::{ |
| 18 | + filter::{filter_fn, FilterFn}, |
| 19 | + layer::Layer, |
| 20 | + }, |
| 21 | +}; |
| 22 | + |
| 23 | +/// Creates a filter that excludes spans with the `opentelemetry.skip` field. |
| 24 | +/// |
| 25 | +/// Any span that declares an `opentelemetry.skip` field will be excluded from export, |
| 26 | +/// regardless of the field's value. This is a limitation of the tracing metadata API. |
| 27 | +/// |
| 28 | +/// Usage examples: |
| 29 | +/// ```ignore |
| 30 | +/// // Always skip this span |
| 31 | +/// #[tracing::instrument(fields(opentelemetry.skip = true))] |
| 32 | +/// fn internal_helper() { } |
| 33 | +/// |
| 34 | +/// // Conditionally skip based on a parameter |
| 35 | +/// #[tracing::instrument(fields(opentelemetry.skip = should_skip))] |
| 36 | +/// fn my_function(should_skip: bool) { |
| 37 | +/// // Will be skipped if should_skip is true when called |
| 38 | +/// // Note: The field must be declared in the span, so the span is |
| 39 | +/// // created with knowledge that it might be skipped |
| 40 | +/// } |
| 41 | +/// ``` |
| 42 | +#[cfg(feature = "opentelemetry")] |
| 43 | +fn opentelemetry_skip_filter() -> FilterFn<impl Fn(&tracing::Metadata<'_>) -> bool> { |
| 44 | + filter_fn(|metadata| { |
| 45 | + if !metadata.is_span() { |
| 46 | + return false; |
| 47 | + } |
| 48 | + metadata.fields().field("opentelemetry.skip").is_none() |
| 49 | + }) |
| 50 | +} |
| 51 | + |
| 52 | +/// Initializes tracing with a custom OpenTelemetry tracer provider. |
| 53 | +/// |
| 54 | +/// This is an internal function used by both production and test code. |
| 55 | +#[cfg(feature = "opentelemetry")] |
| 56 | +fn init_with_tracer_provider(log_name: &str, tracer_provider: SdkTracerProvider) { |
| 57 | + global::set_tracer_provider(tracer_provider.clone()); |
| 58 | + let tracer = tracer_provider.tracer("linera"); |
| 59 | + |
| 60 | + let opentelemetry_layer = |
| 61 | + OpenTelemetryLayer::new(tracer).with_filter(opentelemetry_skip_filter()); |
| 62 | + |
| 63 | + let config = crate::tracing::get_env_config(log_name); |
| 64 | + let maybe_log_file_layer = config.maybe_log_file_layer(); |
| 65 | + let stderr_layer = config.stderr_layer(); |
| 66 | + |
| 67 | + tracing_subscriber::registry() |
| 68 | + .with(opentelemetry_layer) |
| 69 | + .with(config.env_filter) |
| 70 | + .with(maybe_log_file_layer) |
| 71 | + .with(stderr_layer) |
| 72 | + .init(); |
| 73 | +} |
| 74 | + |
| 75 | +/// Builds an OpenTelemetry layer with the opentelemetry.skip filter. |
| 76 | +/// |
| 77 | +/// This is used for testing to avoid setting the global subscriber. |
| 78 | +/// Returns the layer, exporter, and tracer provider (which must be kept alive and shutdown). |
| 79 | +#[cfg(all(with_testing, feature = "opentelemetry"))] |
| 80 | +pub fn build_opentelemetry_layer_with_test_exporter( |
| 81 | + log_name: &str, |
| 82 | +) -> ( |
| 83 | + impl tracing_subscriber::Layer<tracing_subscriber::Registry>, |
| 84 | + InMemorySpanExporter, |
| 85 | + SdkTracerProvider, |
| 86 | +) { |
| 87 | + let exporter = InMemorySpanExporter::default(); |
| 88 | + let exporter_clone = exporter.clone(); |
| 89 | + |
| 90 | + let resource = Resource::builder() |
| 91 | + .with_service_name(log_name.to_string()) |
| 92 | + .build(); |
| 93 | + |
| 94 | + let tracer_provider = SdkTracerProvider::builder() |
| 95 | + .with_resource(resource) |
| 96 | + .with_simple_exporter(exporter) |
| 97 | + .with_sampler(opentelemetry_sdk::trace::Sampler::AlwaysOn) |
| 98 | + .build(); |
| 99 | + |
| 100 | + global::set_tracer_provider(tracer_provider.clone()); |
| 101 | + let tracer = tracer_provider.tracer("linera"); |
| 102 | + let opentelemetry_layer = |
| 103 | + OpenTelemetryLayer::new(tracer).with_filter(opentelemetry_skip_filter()); |
| 104 | + |
| 105 | + (opentelemetry_layer, exporter_clone, tracer_provider) |
| 106 | +} |
| 107 | + |
| 108 | +/// Initializes tracing with OpenTelemetry OTLP exporter. |
| 109 | +/// |
| 110 | +/// Exports traces using the OTLP protocol to any OpenTelemetry-compatible backend. |
| 111 | +/// Requires the `opentelemetry` feature. |
| 112 | +/// Only enables OpenTelemetry if LINERA_OTLP_EXPORTER_ENDPOINT env var is set. |
| 113 | +/// This prevents DNS errors in environments where OpenTelemetry is not deployed. |
| 114 | +#[cfg(feature = "opentelemetry")] |
| 115 | +pub fn init_with_opentelemetry(log_name: &str, otlp_endpoint: Option<&str>) { |
| 116 | + // Check if OpenTelemetry endpoint is configured via parameter or env var |
| 117 | + let endpoint = match otlp_endpoint { |
| 118 | + Some(ep) if !ep.is_empty() => ep.to_string(), |
| 119 | + _ => match std::env::var("LINERA_OTLP_EXPORTER_ENDPOINT") { |
| 120 | + Ok(ep) if !ep.is_empty() => ep, |
| 121 | + _ => { |
| 122 | + eprintln!( |
| 123 | + "LINERA_OTLP_EXPORTER_ENDPOINT not set and no endpoint provided. \ |
| 124 | + Falling back to standard tracing without OpenTelemetry support." |
| 125 | + ); |
| 126 | + crate::tracing::init(log_name); |
| 127 | + return; |
| 128 | + } |
| 129 | + }, |
| 130 | + }; |
| 131 | + |
| 132 | + let resource = Resource::builder() |
| 133 | + .with_service_name(log_name.to_string()) |
| 134 | + .build(); |
| 135 | + |
| 136 | + let exporter = SpanExporter::builder() |
| 137 | + .with_tonic() |
| 138 | + .with_endpoint(endpoint) |
| 139 | + .build() |
| 140 | + .expect("Failed to create OTLP exporter"); |
| 141 | + |
| 142 | + let tracer_provider = SdkTracerProvider::builder() |
| 143 | + .with_resource(resource) |
| 144 | + .with_batch_exporter(exporter) |
| 145 | + .with_sampler(opentelemetry_sdk::trace::Sampler::AlwaysOn) |
| 146 | + .build(); |
| 147 | + |
| 148 | + init_with_tracer_provider(log_name, tracer_provider); |
| 149 | +} |
| 150 | + |
| 151 | +/// Fallback when opentelemetry feature is not enabled. |
| 152 | +#[cfg(not(feature = "opentelemetry"))] |
| 153 | +pub fn init_with_opentelemetry(log_name: &str, _otlp_endpoint: Option<&str>) { |
| 154 | + eprintln!( |
| 155 | + "OTLP export requires the 'opentelemetry' feature to be enabled! Falling back to default tracing initialization." |
| 156 | + ); |
| 157 | + crate::tracing::init(log_name); |
| 158 | +} |
| 159 | + |
| 160 | +/// Guard that flushes Chrome trace file when dropped. |
| 161 | +/// |
| 162 | +/// Store this guard in a variable that lives for the duration of your program. |
| 163 | +/// When it's dropped, the trace file will be completed and closed. |
| 164 | +pub type ChromeTraceGuard = tracing_chrome::FlushGuard; |
| 165 | + |
| 166 | +/// Builds a Chrome trace layer and guard. |
| 167 | +/// |
| 168 | +/// Returns a subscriber and guard. The subscriber should be used with `with_default` |
| 169 | +/// to avoid global state conflicts. |
| 170 | +pub fn build_chrome_trace_layer_with_exporter<W>( |
| 171 | + log_name: &str, |
| 172 | + writer: W, |
| 173 | +) -> (impl tracing::Subscriber + Send + Sync, ChromeTraceGuard) |
| 174 | +where |
| 175 | + W: std::io::Write + Send + 'static, |
| 176 | +{ |
| 177 | + let (chrome_layer, guard) = ChromeLayerBuilder::new().writer(writer).build(); |
| 178 | + |
| 179 | + let config = crate::tracing::get_env_config(log_name); |
| 180 | + let maybe_log_file_layer = config.maybe_log_file_layer(); |
| 181 | + let stderr_layer = config.stderr_layer(); |
| 182 | + |
| 183 | + let subscriber = tracing_subscriber::registry() |
| 184 | + .with(chrome_layer) |
| 185 | + .with(config.env_filter) |
| 186 | + .with(maybe_log_file_layer) |
| 187 | + .with(stderr_layer); |
| 188 | + |
| 189 | + (subscriber, guard) |
| 190 | +} |
| 191 | + |
| 192 | +/// Initializes tracing with Chrome Trace JSON exporter. |
| 193 | +/// |
| 194 | +/// Returns a guard that must be kept alive for the duration of the program. |
| 195 | +/// When the guard is dropped, the trace data is flushed and completed. |
| 196 | +/// |
| 197 | +/// Exports traces to Chrome Trace JSON format which can be visualized in: |
| 198 | +/// - Chrome: `chrome://tracing` |
| 199 | +/// - Perfetto UI: <https://ui.perfetto.dev> |
| 200 | +/// |
| 201 | +/// Note: Uses `try_init()` to avoid panicking if a global subscriber is already set. |
| 202 | +/// In that case, tracing may not work as expected. |
| 203 | +pub fn init_with_chrome_trace_exporter<W>(log_name: &str, writer: W) -> ChromeTraceGuard |
| 204 | +where |
| 205 | + W: std::io::Write + Send + 'static, |
| 206 | +{ |
| 207 | + let (subscriber, guard) = build_chrome_trace_layer_with_exporter(log_name, writer); |
| 208 | + let _ = subscriber.try_init(); |
| 209 | + guard |
| 210 | +} |
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