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[K8sDnsNameResolver] Fix Netty panic logging on JVM shutdown if wrapped in CompletionException #10

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Merged
migesok merged 1 commit into from
Sep 17, 2026
Merged

[K8sDnsNameResolver] Fix Netty panic logging on JVM shutdown if wrapped in CompletionException #10

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36 changes: 33 additions & 3 deletions k8s-dns-name-resolver/src/main/java/com/evolution/jgrpc/tools/k8sdns/K8sDnsNameResolver.java
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Original file line number Diff line number Diff line change
Expand Up @@ -102,8 +102,7 @@ private void refreshInner() {
resolveAllAsync(
(addresses, err) -> {
try {
if (this.isShuttingDown
|| err instanceof NameLookupState.LookupFailedJvmShutdownException) {
if (this.isShuttingDown || hasJvmLookupFailedOnJvmShutdown(err)) {
handleResolutionResultDuringShutdown();
} else if (err != null) {
handleResolutionFailure(err);
Expand Down Expand Up @@ -174,7 +173,7 @@ private void resolveAllAsync(
this.syncCtx.execute(
() -> {
if (err != null) {
if (err instanceof NameLookupState.LookupFailedJvmShutdownException) {
if (hasJvmLookupFailedOnJvmShutdown(err)) {
// lower the level below INFO if it's caused by JVM shutdown
// to keep the shutdown logs clean;
// the error log statement is not actionable in this case
Expand All @@ -199,4 +198,35 @@ private Listener getListener() {
}
return this.listener;
}

/**
* Sometimes the actual exception on shutdown gets wrapped in a CompletionException, to harden the
* check, this method also looks into the cause:
*
* <pre>
* ERROR 2026-09-16 16:08:42,201 c.e.j.t.k.K8sDnsNameResolver - DNS lookup failed
* java.util.concurrent.CompletionException: com.evolution.jgrpc.tools.k8sdns.NameLookupState$LookupFailedJvmShutdownException
* at java.base/java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:332)
* at java.base/java.util.concurrent.CompletableFuture.uniApplyNow(CompletableFuture.java:674)
* at java.base/java.util.concurrent.CompletableFuture.uniApplyStage(CompletableFuture.java:662)
* at java.base/java.util.concurrent.CompletableFuture.thenApply(CompletableFuture.java:2200)
* at java.base/java.util.concurrent.CompletableFuture.thenApply(CompletableFuture.java:144)
* at com.evolution.jgrpc.tools.k8sdns.NameLookupState.lookupByAbsoluteName(NameLookupState.java:173)
* at com.evolution.jgrpc.tools.k8sdns.NameLookupState.runNextLookup(NameLookupState.java:107)
* at com.evolution.jgrpc.tools.k8sdns.K8sDnsNameResolver.resolveAllAsync(K8sDnsNameResolver.java:171)
* at com.evolution.jgrpc.tools.k8sdns.K8sDnsNameResolver.refreshInner(K8sDnsNameResolver.java:102)
* at io.grpc.SynchronizationContext$ManagedRunnable.run(SynchronizationContext.java:213)
* at io.grpc.SynchronizationContext.drain(SynchronizationContext.java:94)
* at io.grpc.SynchronizationContext.execute(SynchronizationContext.java:126)
* at io.grpc.SynchronizationContext$2.run(SynchronizationContext.java:184)
* at io.grpc.netty.shaded.io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
* at io.grpc.netty.shaded.io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:159)
* at io.grpc.netty.shaded.io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:173)
* </pre>
*/
private boolean hasJvmLookupFailedOnJvmShutdown(@Nullable Throwable err) {
return err != null
&& ((err instanceof NameLookupState.LookupFailedJvmShutdownException)
|| (err.getCause() instanceof NameLookupState.LookupFailedJvmShutdownException));
}
}
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