chore: add pre-push hook for cargo fmt and clippy (#130)

* chore: add pre-push hook for cargo fmt and clippy

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* fix: remove unnecessary u32 casts flagged by clippy

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* fix: apply cargo fmt formatting

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* fix: collapse nested if block flagged by clippy

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* Apply suggestions from code review

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* chore: treat clippy warnings as errors in CI and document pre-push hook

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

* fix: bias mini_agent serve() select toward shutdown over task exits

When shutdown_tx fires, each transport accept loop sees shutdown_rx,
drains its joinset, and returns Ok(()). Both the accept loop's
JoinHandle and the supervisor's shutdown_rx.changed() then become ready
in the same poll cycle. Without biased, the unbiased select! in serve()
would pick a *Died arm at random, return Err(...), and abort everything
without firing flusher_shutdown_tx — so the stats flusher's shutdown
branch never ran and no final stats POST happened. This made
test_mini_agent_*_with_real_flushers intermittently time out at 60s
waiting for /api/v0.2/stats; CI run 25562651282 captured the smoking
gun "Event::PipeDied: Ok(Ok(()))".

biased; with shutdown_rx.changed() listed first guarantees Event::Shutdown
wins whenever the shutdown signal is observable, so the supervisor always
takes the graceful-flush path even if the accept loops happen to resolve
first. Production main.rs never sends on shutdown_tx, so this is purely
a test-only path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: 3 people

.githooks/pre-push

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+echo ">>> [pre-push] Running cargo fmt --check..."
+if ! cargo fmt --all -- --check; then
+    echo ""
+    echo "HOOK FAILED: cargo fmt check failed."
+    echo "Try 'cargo fmt --all' then re-attempt the push."
+    exit 1
+fi
+
+echo ">>> [pre-push] Running cargo clippy..."
+if ! cargo clippy --workspace --all-targets --all-features -- -D warnings; then
+    echo ""
+    echo "HOOK FAILED: cargo clippy reported warnings or errors."
+    echo "Fix the clippy diagnostics above, then re-attempt the push."
+    exit 1
+fi
+
+echo ">>> [pre-push] All checks passed."

.github/workflows/cargo.yml

@@ -60,7 +60,7 @@ jobs:
             # doesn't fail.
             export AWS_LC_FIPS_SYS_NO_ASM=1
           fi
-          cargo clippy --workspace --all-features
+          cargo clippy --workspace --all-features -- -D warnings
 
   build:
     name: Build

README.md

@@ -1,3 +1,11 @@
 # Serverless Components
 
-A collection of libraries and binaries used for instrumenting AWS Lambda Functions, Azure Functions, and Azure Spring Apps.
+A collection of libraries and binaries used for instrumenting AWS Lambda Functions, Azure Functions, and Azure Spring Apps.
+
+## Development
+
+Install the git pre-push hook (runs `cargo fmt --check` and `cargo clippy -D warnings` before each push):
+
+```sh
+git config core.hooksPath .githooks
+```

crates/datadog-trace-agent/src/mini_agent.rs

@@ -295,13 +295,19 @@ impl MiniAgent {
             };
             tokio::pin!(concentrator_exit);
 
+            // biased: when shutdown_tx fires, the accept loops also see
+            // shutdown_rx and exit cleanly. Their JoinHandles resolve in the
+            // same poll cycle as our shutdown_rx.changed(); without biased,
+            // a *Died arm can win the race and abort the supervisor before
+            // it has a chance to signal the stats flusher to flush.
             tokio::select! {
+                biased;
+                _ = shutdown_rx.changed() => Event::Shutdown,
                 r = &mut tcp_exit => Event::TcpDied(format!("{r:?}")),
                 r = &mut pipe_exit => Event::PipeDied(format!("{r:?}")),
                 r = &mut trace_flusher_handle => Event::TraceFlusherDied(format!("{r:?}")),
                 r = &mut stats_flusher_handle => Event::StatsFlusherDied(format!("{r:?}")),
                 r = &mut concentrator_exit => Event::ConcentratorDied(format!("{r:?}")),
-                _ = shutdown_rx.changed() => Event::Shutdown,
             }
         };
         #[cfg(not(all(windows, feature = "windows-pipes")))]
@@ -322,12 +328,14 @@ impl MiniAgent {
             };
             tokio::pin!(concentrator_exit);
 
+            // biased: see Windows branch above for rationale.
             tokio::select! {
+                biased;
+                _ = shutdown_rx.changed() => Event::Shutdown,
                 r = &mut tcp_exit => Event::TcpDied(format!("{r:?}")),
                 r = &mut trace_flusher_handle => Event::TraceFlusherDied(format!("{r:?}")),
                 r = &mut stats_flusher_handle => Event::StatsFlusherDied(format!("{r:?}")),
                 r = &mut concentrator_exit => Event::ConcentratorDied(format!("{r:?}")),
-                _ = shutdown_rx.changed() => Event::Shutdown,
             }
         };
 

crates/datadog-trace-agent/tests/integration_test.rs

@@ -385,11 +385,11 @@ async fn test_mini_agent_tcp_with_real_flushers() {
     let mut server_ready = false;
     for _ in 0..20 {
         tokio::time::sleep(Duration::from_millis(50)).await;
-        if let Ok(response) = send_tcp_request(test_port, "/info", "GET", None, &[]).await {
-            if response.status().is_success() {
-                server_ready = true;
-                break;
-            }
+        if let Ok(response) = send_tcp_request(test_port, "/info", "GET", None, &[]).await
+            && response.status().is_success()
+        {
+            server_ready = true;
+            break;
         }
     }
     assert!(

crates/dogstatsd/src/origin.rs

@@ -310,16 +310,13 @@ mod tests {
             timestamp: 0,
         };
         let origin = metric.find_origin(tags).unwrap();
+        assert_eq!(origin.origin_product, OriginProduct::Serverless as u32);
         assert_eq!(
-            origin.origin_product as u32,
-            OriginProduct::Serverless as u32
-        );
-        assert_eq!(
-            origin.origin_category as u32,
+            origin.origin_category,
             OriginCategory::AzureFunctionsMetrics as u32
         );
         assert_eq!(
-            origin.origin_service as u32,
+            origin.origin_service,
             OriginService::ServerlessEnhanced as u32
         );
     }