remove shutdown from signal handler

Signed-off-by: Ziy1-Tan <[email protected]>

vmm/common/Cargo.toml

@@ -18,6 +18,8 @@ ttrpc = { version = "0.7", features = ["async"] }
 protobuf = "3.2"
 async-trait = "0.1"
 regex = "1.5.6"
+futures = { version = "0.3.21" }
+signal-hook-tokio = { version = "0.3.1", features = ["futures-v0_3"] }
 
 tracing = "0.1.40"
 tracing-opentelemetry = "0.21.0"
@@ -26,8 +28,6 @@ tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 opentelemetry = { version = "0.20.0", features = ["rt-tokio"] }
 opentelemetry-otlp = "0.13.0"
 
-signal-hook = "0.3.1"
-
 [build-dependencies]
 ttrpc-codegen = { git = "https://github.com/kuasar-io/ttrpc-rust.git", branch = "v0.7.1-kuasar" }
 tonic-build = "0.7.2"

vmm/common/src/signal.rs

@@ -14,16 +14,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-use nix::libc::{SIGINT, SIGTERM, SIGUSR1};
-use signal_hook::iterator::Signals;
+use futures::StreamExt;
+use nix::libc;
+use signal_hook_tokio::Signals;
 
 use crate::trace;
 
 pub async fn handle_signals(log_level: &str, otlp_service_name: &str) {
-    let mut signals = Signals::new([SIGTERM, SIGINT, SIGUSR1]).expect("new signal failed");
+    let mut signals = Signals::new([libc::SIGUSR1])
+        .expect("new signal failed")
+        .fuse();
 
-    for sig in signals.forever() {
-        if sig == SIGUSR1 {
+    while let Some(sig) = signals.next().await {
+        if sig == libc::SIGUSR1 {
             trace::set_enabled(!trace::is_enabled());
             let _ = trace::setup_tracing(log_level, otlp_service_name);
         }

vmm/common/src/trace.rs

@@ -30,28 +30,27 @@ use tracing_subscriber::{
 };
 
 lazy_static! {
-    static ref ENABLED: AtomicBool = AtomicBool::new(false);
+    static ref TRACE_ENABLED: AtomicBool = AtomicBool::new(false);
 }
 
 pub fn is_enabled() -> bool {
-    ENABLED.load(Ordering::Relaxed)
+    TRACE_ENABLED.load(Ordering::Relaxed)
 }
 
 pub fn set_enabled(enabled: bool) {
-    ENABLED.store(enabled, Ordering::Relaxed);
+    TRACE_ENABLED.store(enabled, Ordering::Relaxed);
 }
 
 pub fn setup_tracing(log_level: &str, otlp_service_name: &str) -> anyhow::Result<()> {
     let env_filter = init_logger_filter(log_level)
         .map_err(|e| anyhow!("failed to init logger filter: {}", e))?;
 
     let mut layers = vec![tracing_subscriber::fmt::layer().boxed()];
+    // TODO: shutdown tracer provider when is_enabled is false
     if is_enabled() {
         let tracer = init_otlp_tracer(otlp_service_name)
             .map_err(|e| anyhow!("failed to init otlp tracer: {}", e))?;
         layers.push(tracing_opentelemetry::layer().with_tracer(tracer).boxed());
-    } else {
-        shutdown_tracing();
     }
 
     Registry::default()
@@ -79,6 +78,8 @@ pub fn init_otlp_tracer(otlp_service_name: &str) -> anyhow::Result<Tracer> {
     Ok(tracer)
 }
 
+// TODO: may hang indefinitely, use it again when https://github.com/open-telemetry/opentelemetry-rust/issues/868 is resolved
+#[allow(dead_code)]
 pub fn shutdown_tracing() {
     global::shutdown_tracer_provider();
 }

vmm/task/src/main.rs

@@ -183,12 +183,11 @@ fn init_logger(log_level: &str) -> anyhow::Result<()> {
         .add_directive(format!("vmm_task={}", log_level).parse()?);
 
     let mut layers = vec![tracing_subscriber::fmt::layer().boxed()];
+    // TODO: shutdown tracer provider when is_enabled is false
     if trace::is_enabled() {
         let tracer = trace::init_otlp_tracer("kuasar-vmm-task-service")
             .map_err(|e| anyhow!("failed to init otlp tracer: {}", e))?;
         layers.push(tracing_opentelemetry::layer().with_tracer(tracer).boxed());
-    } else {
-        trace::shutdown_tracing();
     }
 
     Registry::default()
@@ -254,8 +253,6 @@ async fn handle_signals(signals: Signals, log_level: &str) {
     while let Some(sig) = signals.next().await {
         match sig {
             libc::SIGTERM | libc::SIGINT => {
-                trace::set_enabled(false);
-                trace::shutdown_tracing();
                 debug!("received {}", sig);
             }
             libc::SIGCHLD => loop {