patagia-control/controller/src/instrumentation.rs

use anyhow::{anyhow, Result};
use once_cell::sync::Lazy;
use opentelemetry::{trace::TracerProvider as _, KeyValue};
use opentelemetry_appender_tracing::layer::OpenTelemetryTracingBridge;
use opentelemetry_sdk::{
    logs::LoggerProvider,
    metrics::{MeterProviderBuilder, PeriodicReader, SdkMeterProvider},
    runtime,
    trace::{RandomIdGenerator, Sampler, TracerProvider},
    Resource,
};
use tracing_opentelemetry::{MetricsLayer, OpenTelemetryLayer};
use tracing_subscriber::layer::SubscriberExt;
use tracing_subscriber::util::SubscriberInitExt;

static RESOURCE: Lazy<Resource> = Lazy::new(|| {
    Resource::new(vec![
        KeyValue::new(
            opentelemetry_semantic_conventions::resource::SERVICE_NAME,
            env!("CARGO_PKG_NAME"),
        ),
        KeyValue::new(
            opentelemetry_semantic_conventions::resource::SERVICE_VERSION,
            env!("CARGO_PKG_VERSION"),
        ),
    ])
});

// Construct LoggingProdiver for LoggingLayer
fn init_logging_provider() -> Result<LoggerProvider> {
    let exporter = opentelemetry_otlp::LogExporter::builder()
        .with_tonic()
        .build()?;
    let logging_provider: LoggerProvider = LoggerProvider::builder()
        .with_resource(RESOURCE.clone())
        .with_batch_exporter(exporter, runtime::Tokio)
        .build();
    Ok(logging_provider)
}

// Construct MeterProvider for MetricsLayer
fn init_meter_provider() -> Result<SdkMeterProvider> {
    let exporter = opentelemetry_otlp::MetricExporter::builder()
        .with_tonic()
        .with_temporality(opentelemetry_sdk::metrics::Temporality::default())
        .build()
        .map_err(|e| anyhow!("Error creating OTLP metric exporter: {:?}", e))?;

    let meter_provider = MeterProviderBuilder::default()
        .with_resource(RESOURCE.clone())
        .with_reader(
            PeriodicReader::builder(exporter, runtime::Tokio)
                .with_interval(std::time::Duration::from_secs(10))
                .build(),
        )
        .build();

    opentelemetry::global::set_meter_provider(meter_provider.clone());

    Ok(meter_provider)
}

// Construct TracerProvider for OpenTelemetryLayer
fn init_tracer_provider() -> Result<TracerProvider> {
    let exporter = opentelemetry_otlp::SpanExporter::builder()
        .with_tonic()
        .build()
        .map_err(|e| anyhow!("Error creating OTLP span exporter: {:?}", e))?;

    let tracer_provider = opentelemetry_sdk::trace::TracerProvider::builder()
        .with_config(
            opentelemetry_sdk::trace::Config::default()
                .with_sampler(Sampler::ParentBased(Box::new(Sampler::TraceIdRatioBased(
                    1.0,
                ))))
                .with_id_generator(RandomIdGenerator::default())
                .with_resource(RESOURCE.clone()),
        )
        .with_batch_exporter(exporter, opentelemetry_sdk::runtime::Tokio)
        .build();

    Ok(tracer_provider)
}

// Initialize tracing-subscriber and return OtelGuard for opentelemetry-related termination processing
pub fn init_tracing_subscriber() -> Result<OtelGuard> {
    let logging_provider = init_logging_provider()?;
    let meter_provider = init_meter_provider()?;
    let tracer_provider = init_tracer_provider()?;

    let tracer = tracer_provider.tracer("tracing-otel-subscriber");

    tracing_subscriber::registry()
        .with(tracing_subscriber::EnvFilter::from_default_env())
        .with(tracing_subscriber::fmt::layer())
        .with(MetricsLayer::new(meter_provider.clone()))
        .with(OpenTelemetryLayer::new(tracer))
        .with(OpenTelemetryTracingBridge::new(&logging_provider))
        .init();

    Ok(OtelGuard {
        logging_provider,
        meter_provider,
        tracer_provider,
    })
}

pub struct OtelGuard {
    logging_provider: LoggerProvider,
    meter_provider: SdkMeterProvider,
    tracer_provider: TracerProvider,
}

impl Drop for OtelGuard {
    fn drop(&mut self) {
        if let Err(err) = self.tracer_provider.shutdown() {
            eprintln!("{err:?}");
        }
        if let Err(err) = self.logging_provider.shutdown() {
            eprintln!("{err:?}");
        }
        if let Err(err) = self.meter_provider.shutdown() {
            eprintln!("{err:?}");
        }
    }
}