feat: add opentelemetry tracing support

fhevm-engine/coprocessor/Cargo.toml

@@ -35,6 +35,10 @@ prometheus.workspace = true
 log.workspace = true
 structured-logger = "1.0.3"
 actix-web = "4.9.0"
+opentelemetry = "0.25"
+opentelemetry-otlp = "0.25"
+opentelemetry_sdk = { version = "0.25", features = ["rt-tokio"] }
+tonic-tracing-opentelemetry = "0.21"
 
 [dev-dependencies]
 testcontainers = "0.21"

fhevm-engine/coprocessor/src/main.rs

@@ -10,6 +10,7 @@ mod tfhe_worker;
 mod types;
 mod utils;
 mod metrics;
+mod tracing;
 
 fn main() {
     let args = crate::cli::parse_args();
@@ -64,6 +65,10 @@ async fn async_main(
         .with_default_writer(structured_logger::async_json::new_writer(tokio::io::stdout()))
         .init();
 
+    if let Err(err) = tracing::setup_tracing() {
+        panic!("Error while initializing tracing: {:?}", err);
+    }
+
     let mut set = JoinSet::new();
     if args.run_server {
         log::info!(target: "async_main", "Initializing api server");

fhevm-engine/coprocessor/src/server.rs

@@ -132,6 +132,7 @@ pub async fn run_server_iteration(
     };
 
     Server::builder()
+        .layer(tonic_tracing_opentelemetry::middleware::server::OtelGrpcLayer::default())
         .add_service(
             crate::server::coprocessor::fhevm_coprocessor_server::FhevmCoprocessorServer::new(
                 service,