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Recompute cached value when the Redis connection fails.
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If the Redis client cannot connect to Redis (and only in this case), recompute the value.
The value is neither cached nor written in the cache, making the cache implementation more robust to transient network issues.
A log message (warning) has been added to detect the issue.

Co-authored-by: Monhemius, B. (Bart) <[email protected]>
Co-authored-by: Clement Escoffier <[email protected]>
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@bartm-dvb @cescoffier
bartm-dvb and cescoffier committed Sep 18, 2023
1 parent 54df528 commit c2b4860
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Showing 2 changed files with 77 additions and 14 deletions.
46 changes: 33 additions & 13 deletions ...ions/redis-cache/runtime/src/main/java/io/quarkus/cache/redis/runtime/RedisCacheImpl.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
package io.quarkus.cache.redis.runtime;

import java.net.ConnectException;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.List;
Expand All @@ -10,6 +11,8 @@
import java.util.function.Predicate;
import java.util.function.Supplier;

import org.jboss.logging.Logger;

import io.quarkus.arc.Arc;
import io.quarkus.arc.ArcContainer;
import io.quarkus.cache.CacheException;
Expand All @@ -35,6 +38,8 @@
*/
public class RedisCacheImpl extends AbstractCache implements RedisCache {

private static final Logger log = Logger.getLogger(RedisCacheImpl.class);

private static final Map<String, Class<?>> PRIMITIVE_TO_CLASS_MAPPING = Map.of(
"int", Integer.class,
"byte", Byte.class,
Expand Down Expand Up @@ -123,6 +128,19 @@ private <K> String encodeKey(K key) {
return new String(marshaller.encode(key), StandardCharsets.UTF_8);
}

private <K, V> Uni<V> computeValue(K key, Function<K, V> valueLoader, boolean isWorkerThread) {
if (isWorkerThread) {
return Uni.createFrom().item(new Supplier<V>() {
@Override
public V get() {
return valueLoader.apply(key);
}
}).runSubscriptionOn(MutinyHelper.blockingExecutor(vertx.getDelegate()));
} else {
return Uni.createFrom().item(valueLoader.apply(key));
}
}

@Override
public <K, V> Uni<V> get(K key, Class<V> clazz, Function<K, V> valueLoader) {
// With optimistic locking:
Expand All @@ -148,17 +166,7 @@ public Uni<V> apply(V cached) throws Exception {
if (cached != null) {
return Uni.createFrom().item(new StaticSupplier<>(cached));
} else {
Uni<V> uni;
if (isWorkerThread) {
uni = Uni.createFrom().item(new Supplier<V>() {
@Override
public V get() {
return valueLoader.apply(key);
}
}).runSubscriptionOn(MutinyHelper.blockingExecutor(vertx.getDelegate()));
} else {
uni = Uni.createFrom().item(valueLoader.apply(key));
}
Uni<V> uni = computeValue(key, valueLoader, isWorkerThread);

return uni.onItem().call(new Function<V, Uni<?>>() {
@Override
Expand All @@ -185,7 +193,15 @@ public Uni<?> apply(V value) {
}
}));
}
});
})

.onFailure(ConnectException.class).recoverWithUni(new Function<Throwable, Uni<? extends V>>() {
@Override
public Uni<? extends V> apply(Throwable e) {
log.warn("Unable to connect to Redis, recomputing cached value", e);
return computeValue(key, valueLoader, isWorkerThread);
}
});
}

@Override
Expand Down Expand Up @@ -215,7 +231,11 @@ public Uni<V> apply(RedisConnection connection) {
}
});
}
});
})
.onFailure(ConnectException.class).recoverWithUni(e -> {
log.warn("Unable to connect to Redis, recomputing cached value", e);
return valueLoader.apply(key);
});
}

@Override
Expand Down
45 changes: 44 additions & 1 deletion .../redis-cache/runtime/src/test/java/io/quarkus/cache/redis/runtime/RedisCacheImplTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,12 @@ class RedisCacheImplTest extends RedisCacheTestBase {

@AfterEach
void clear() {
redis.send(Request.cmd(Command.FLUSHALL).arg("SYNC")).await().atMost(Duration.ofSeconds(10));
try {
redis.send(Request.cmd(Command.FLUSHALL).arg("SYNC")).await()
.atMost(Duration.ofSeconds(10));
} catch (Exception ignored) {
// ignored.
}
}

@Test
Expand All @@ -45,6 +50,18 @@ public void testPutInTheCache() {
assertThat(r).isNotNull();
}

@Test
public void testPutInTheCacheWithoutRedis() {
String k = UUID.randomUUID().toString();
RedisCacheInfo info = new RedisCacheInfo();
info.name = "foo";
info.valueType = String.class.getName();
info.expireAfterWrite = Optional.of(Duration.ofSeconds(2));
RedisCacheImpl cache = new RedisCacheImpl(info, vertx, redis, BLOCKING_ALLOWED);
server.close();
assertThat(cache.get(k, s -> "hello").await().indefinitely()).isEqualTo("hello");
}

@Test
public void testPutInTheCacheWithOptimisticLocking() {
String k = UUID.randomUUID().toString();
Expand Down Expand Up @@ -355,6 +372,32 @@ void testAsyncGetWithDefaultType() {
}));
}

@Test
void testAsyncGetWithDefaultTypeWithoutRedis() {
RedisCacheInfo info = new RedisCacheInfo();
info.name = "star-wars";
info.expireAfterWrite = Optional.of(Duration.ofSeconds(2));
info.valueType = Person.class.getName();
RedisCacheImpl cache = new RedisCacheImpl(info, vertx, redis, BLOCKING_ALLOWED);

server.close();

assertThat(cache
.getAsync("test",
x -> Uni.createFrom().item(new Person("luke", "skywalker"))
.runSubscriptionOn(Infrastructure.getDefaultExecutor()))
.await().indefinitely()).satisfies(p -> {
assertThat(p.firstName).isEqualTo("luke");
assertThat(p.lastName).isEqualTo("skywalker");
});

assertThat(cache.getAsync("test", x -> Uni.createFrom().item(new Person("leia", "organa")))
.await().indefinitely()).satisfies(p -> {
assertThat(p.firstName).isEqualTo("leia");
assertThat(p.lastName).isEqualTo("organa");
});
}

@Test
void testAsyncGetWithDefaultTypeWithOptimisticLocking() {
RedisCacheInfo info = new RedisCacheInfo();
Expand Down

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