#194 Check ready state of redis before using it

README.md

@@ -219,9 +219,10 @@ The following configuration values are available:
 | deltaEtagsPrefix                        | redis  | delta:etags              | The prefix for delta etags redis keys                                                                                                 |
 | lockPrefix                              | redis  | rest-storage:locks       | The prefix for lock redis keys                                                                                                        |
 | resourceCleanupAmount                   | redis  | 100000                   | The maximum amount of resources to clean in a single cleanup run                                                                      |
-| resourceCleanupIntervalSec              | redis  |                          | The interval (in seconds) how often to peform the storage cleanup. When set to _null_ no periodic storage cleanup is peformed         |
+| resourceCleanupIntervalSec              | redis  |                          | The interval (in seconds) how often to perform the storage cleanup. When set to _null_ no periodic storage cleanup is performed       |
 | rejectStorageWriteOnLowMemory           | redis  | false                    | When set to _true_, PUT requests with the x-importance-level header can be rejected when memory gets low                              |
 | freeMemoryCheckIntervalMs               | redis  | 60000                    | The interval in milliseconds to calculate the actual memory usage                                                                     |
+| redisReadyCheckIntervalMs               | redis  | -1                       | The interval in milliseconds to calculate the "ready state" of redis. When value < 1, no "ready state" will be calculated             |
 
 ### Configuration util
 

src/main/java/org/swisspush/reststorage/RedisRestStorageRunner.java

@@ -20,6 +20,7 @@ public static void main(String[] args) {
                 .storageType(ModuleConfiguration.StorageType.redis)
                 .redisReconnectAttempts(-1)
                 .redisPoolRecycleTimeoutMs(-1)
+                .redisReadyCheckIntervalMs(10000)
                 .resourceCleanupIntervalSec(10);
 
         Vertx.vertx().deployVerticle(new RestStorageMod(),

src/main/java/org/swisspush/reststorage/RestStorageHandler.java

@@ -8,7 +8,6 @@
 import io.vertx.core.http.HttpServerResponse;
 import io.vertx.core.json.JsonArray;
 import io.vertx.core.json.JsonObject;
-import io.vertx.core.spi.ExecutorServiceFactory;
 import io.vertx.core.streams.Pump;
 import io.vertx.ext.auth.authentication.AuthenticationProvider;
 import io.vertx.ext.web.Router;

src/main/java/org/swisspush/reststorage/RestStorageMod.java

@@ -6,6 +6,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.swisspush.reststorage.exception.RestStorageExceptionFactory;
+import org.swisspush.reststorage.redis.DefaultRedisProvider;
 import org.swisspush.reststorage.redis.RedisProvider;
 import org.swisspush.reststorage.redis.RedisStorage;
 import org.swisspush.reststorage.util.ModuleConfiguration;

src/main/java/org/swisspush/reststorage/DefaultRedisProvider.java → src/main/java/org/swisspush/reststorage/redis/DefaultRedisProvider.java

@@ -1,4 +1,4 @@
-package org.swisspush.reststorage;
+package org.swisspush.reststorage.redis;
 
 import io.vertx.core.Future;
 import io.vertx.core.Promise;
@@ -11,7 +11,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.swisspush.reststorage.exception.RestStorageExceptionFactory;
-import org.swisspush.reststorage.redis.RedisProvider;
 import org.swisspush.reststorage.util.ModuleConfiguration;
 
 import java.util.ArrayList;
@@ -36,26 +35,42 @@ public class DefaultRedisProvider implements RedisProvider {
     private Redis redis;
     private final AtomicBoolean connecting = new AtomicBoolean();
     private RedisConnection client;
+    private RedisReadyProvider readyProvider;
 
     private final AtomicReference<Promise<RedisAPI>> connectPromiseRef = new AtomicReference<>();
 
     public DefaultRedisProvider(
-        Vertx vertx,
-        ModuleConfiguration configuration,
-        RestStorageExceptionFactory exceptionFactory
+            Vertx vertx,
+            ModuleConfiguration configuration,
+            RestStorageExceptionFactory exceptionFactory
     ) {
         this.vertx = vertx;
         this.configuration = configuration;
         this.exceptionFactory = exceptionFactory;
+
+        maybeInitRedisReadyProvider();
+    }
+
+    private void maybeInitRedisReadyProvider() {
+        if (configuration.getRedisReadyCheckIntervalMs() > 0) {
+            this.readyProvider = new DefaultRedisReadyProvider(vertx, configuration.getRedisReadyCheckIntervalMs());
+        }
     }
 
     @Override
     public Future<RedisAPI> redis() {
-        if (redisAPI != null) {
-            return Future.succeededFuture(redisAPI);
-        } else {
+        if(redisAPI == null) {
             return setupRedisClient();
         }
+        if(readyProvider == null) {
+            return Future.succeededFuture(redisAPI);
+        }
+        return readyProvider.ready(redisAPI).compose(ready -> {
+            if (ready) {
+                return Future.succeededFuture(redisAPI);
+            }
+            return Future.failedFuture("Not yet ready!");
+        });
     }
 
     private boolean reconnectEnabled() {

src/main/java/org/swisspush/reststorage/redis/DefaultRedisReadyProvider.java

@@ -0,0 +1,93 @@
+package org.swisspush.reststorage.redis;
+
+import io.vertx.core.Future;
+import io.vertx.core.Vertx;
+import io.vertx.redis.client.RedisAPI;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * Default implementation of the {@link RedisReadyProvider} based on the <code>INFO</code> command in Redis
+ *
+ * @author https://github.com/mcweba [Marc-Andre Weber]
+ */
+public class DefaultRedisReadyProvider implements RedisReadyProvider {
+
+    private static final Logger log = LoggerFactory.getLogger(DefaultRedisReadyProvider.class);
+    private static final String DELIMITER = ":";
+    private static final String LOADING = "loading";
+    final AtomicBoolean redisReady = new AtomicBoolean(true);
+    final AtomicBoolean updateRedisReady = new AtomicBoolean(true);
+
+    /**
+     * Constructor defining the "ready-state" update interval
+     * @param vertx
+     * @param updateIntervalMs interval in ms how often to update the "ready-state"
+     */
+    public DefaultRedisReadyProvider(Vertx vertx, int updateIntervalMs) {
+        vertx.setPeriodic(updateIntervalMs, l -> {
+           updateRedisReady.set(true);
+        });
+    }
+
+    @Override
+    public Future<Boolean> ready(RedisAPI redisAPI) {
+        if(updateRedisReady.compareAndSet(true, false)){
+            return updateRedisReadyState(redisAPI);
+        }
+        return Future.succeededFuture(redisReady.get());
+    }
+
+    /**
+     * Call the <code>INFO</code> command in Redis with a constraint to persistence related information
+     *
+     * @param redisAPI
+     * @return async boolean true when Redis is ready, otherwise false
+     */
+    public Future<Boolean> updateRedisReadyState(RedisAPI redisAPI) {
+        return redisAPI.info(List.of("Persistence")).compose(response -> {
+            boolean ready = getReadyStateFromResponse(response.toString());
+            redisReady.set(ready);
+            return Future.succeededFuture(ready);
+        }, throwable -> {
+            log.error("Error reading redis info", throwable);
+            redisReady.set(false);
+            return Future.succeededFuture(false);
+        });
+    }
+
+    /**
+     * Check the response having a <code>loading:0</code> entry. If so, Redis is ready. When the response contains a
+     * <code>loading:1</code> entry or not related entry at all, we consider Redis to be not ready
+     *
+     * @param persistenceInfo the response from Redis _INFO_ command
+     * @return boolean true when Redis is ready, otherwise false
+     */
+    private boolean getReadyStateFromResponse(String persistenceInfo) {
+        byte loadingValue;
+        try {
+            Optional<String> loadingOpt = persistenceInfo
+                    .lines()
+                    .filter(source -> source.startsWith(LOADING + DELIMITER))
+                    .findAny();
+            if (loadingOpt.isEmpty()) {
+                log.warn("No 'loading' section received from redis. Unable to calculate ready state");
+                return false;
+            }
+            loadingValue = Byte.parseByte(loadingOpt.get().split(DELIMITER)[1]);
+            if (loadingValue == 0) {
+                return true;
+            }
+
+        } catch (NumberFormatException ex) {
+            log.warn("Invalid 'loading' section received from redis. Unable to calculate ready state");
+            return false;
+        }
+
+        return false;
+    }
+}

src/main/java/org/swisspush/reststorage/redis/RedisReadyProvider.java

@@ -0,0 +1,21 @@
+package org.swisspush.reststorage.redis;
+
+import io.vertx.core.Future;
+import io.vertx.redis.client.RedisAPI;
+
+/**
+ * Provides the "ready state" of the Redis database. The connection to Redis may be already established, but Redis is not
+ * yet ready to be used
+ *
+ * @author https://github.com/mcweba [Marc-Andre Weber]
+ */
+public interface RedisReadyProvider {
+
+    /**
+     * Get the "ready state" of the Redis database.
+     *
+     * @param redisAPI API to access redis database
+     * @return An async boolean true when Redis can be used. Returns async boolean false otherwise or in case of an error
+     */
+    Future<Boolean> ready(RedisAPI redisAPI);
+}

src/main/java/org/swisspush/reststorage/redis/RedisStorage.java

@@ -213,6 +213,7 @@ public Future<Optional<Float>> calculateCurrentMemoryUsage() {
                 log.error("Unable to get memory information from redis",
                         exceptionFactory.newException("redisProvider.redis() failed", ev.cause()));
                 promise.complete(Optional.empty());
+                return;
             }
             var redisAPI = ev.result();
             redisAPI.info(Collections.singletonList("memory"), memoryInfo -> {

src/main/java/org/swisspush/reststorage/util/ModuleConfiguration.java

@@ -50,6 +50,7 @@ public enum StorageType {
     private int redisReconnectAttempts = 0;
     private int redisReconnectDelaySec = 30;
     private int redisPoolRecycleTimeoutMs = 180_000;
+    private int redisReadyCheckIntervalMs = -1;
     private String redisPassword = null;
     private String redisUser = null;
     private String expirablePrefix = "rest-storage:expirable";
@@ -170,6 +171,11 @@ public ModuleConfiguration redisPoolRecycleTimeoutMs(int redisPoolRecycleTimeout
         return this;
     }
 
+    public ModuleConfiguration redisReadyCheckIntervalMs(int redisReadyCheckIntervalMs) {
+        this.redisReadyCheckIntervalMs = redisReadyCheckIntervalMs;
+        return this;
+    }
+
     @Deprecated(since = "3.0.17")
     public ModuleConfiguration redisAuth(String redisAuth) {
         this.redisAuth = redisAuth;
@@ -357,6 +363,10 @@ public int getRedisPoolRecycleTimeoutMs() {
         return redisPoolRecycleTimeoutMs;
     }
 
+    public int getRedisReadyCheckIntervalMs() {
+        return redisReadyCheckIntervalMs;
+    }
+
     public boolean isRedisEnableTls() {
         return redisEnableTls;
     }

src/test/java/org/swisspush/reststorage/redis/DefaultRedisReadyProviderTest.java

@@ -0,0 +1,106 @@
+package org.swisspush.reststorage.redis;
+
+import io.vertx.core.AsyncResult;
+import io.vertx.core.Future;
+import io.vertx.core.Vertx;
+import io.vertx.core.buffer.Buffer;
+import io.vertx.ext.unit.Async;
+import io.vertx.ext.unit.TestContext;
+import io.vertx.ext.unit.junit.VertxUnitRunner;
+import io.vertx.redis.client.RedisAPI;
+import io.vertx.redis.client.impl.types.BulkType;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.swisspush.reststorage.util.ResourcesUtils;
+
+import static org.mockito.Mockito.*;
+
+/**
+ * Tests for the {@link DefaultRedisReadyProvider} class
+ *
+ * @author https://github.com/mcweba [Marc-Andre Weber]
+ */
+@RunWith(VertxUnitRunner.class)
+public class DefaultRedisReadyProviderTest {
+
+    private final String REDIS_INFO_LOADING = ResourcesUtils.loadResource("redis_info_persistance_loading_1", true);
+    private final String REDIS_INFO_NOT_LOADING = ResourcesUtils.loadResource("redis_info_persistance_loading_0", true);
+
+    private Vertx vertx;
+    private RedisAPI redisAPI;
+    private DefaultRedisReadyProvider readyProvider;
+
+    @Before
+    public void setUp() {
+        this.vertx = Vertx.vertx();
+        redisAPI = Mockito.mock(RedisAPI.class);
+        readyProvider = new DefaultRedisReadyProvider(vertx, 1000);
+    }
+
+    private void assertReadiness(TestContext testContext, AsyncResult<Boolean> event, Boolean expectedReadiness) {
+        testContext.assertTrue(event.succeeded());
+        testContext.assertEquals(expectedReadiness, event.result());
+    }
+
+    @Test
+    public void testRedisReady(TestContext testContext) {
+        Async async = testContext.async();
+        Mockito.when(redisAPI.info(any())).thenReturn(Future.succeededFuture(BulkType.create(Buffer.buffer(REDIS_INFO_NOT_LOADING), false)));
+
+        readyProvider.ready(redisAPI).onComplete(event -> {
+            assertReadiness(testContext, event, true);
+            async.complete();
+        });
+    }
+
+    @Test
+    public void testRedisReadyMultipleCalls(TestContext testContext) {
+        Async async = testContext.async();
+        Mockito.when(redisAPI.info(any())).thenReturn(Future.succeededFuture(BulkType.create(Buffer.buffer(REDIS_INFO_NOT_LOADING), false)));
+
+        readyProvider.ready(redisAPI).onComplete(event -> {
+            assertReadiness(testContext, event, true);
+            readyProvider.ready(redisAPI).onComplete(event2 -> {
+                assertReadiness(testContext, event2, true);
+                async.complete();
+            });
+        });
+
+        verify(redisAPI, times(1)).info(any());
+    }
+
+    @Test
+    public void testRedisNotReady(TestContext testContext) {
+        Async async = testContext.async();
+        Mockito.when(redisAPI.info(any())).thenReturn(Future.succeededFuture(BulkType.create(Buffer.buffer(REDIS_INFO_LOADING), false)));
+
+        readyProvider.ready(redisAPI).onComplete(event -> {
+            assertReadiness(testContext, event, false);
+            async.complete();
+        });
+    }
+
+    @Test
+    public void testRedisNotReadyInvalidInfoResponse(TestContext testContext) {
+        Async async = testContext.async();
+        Mockito.when(redisAPI.info(any())).thenReturn(Future.succeededFuture(BulkType.create(Buffer.buffer("some invalid info response"), false)));
+
+        readyProvider.ready(redisAPI).onComplete(event -> {
+            assertReadiness(testContext, event, false);
+            async.complete();
+        });
+    }
+
+    @Test
+    public void testRedisNotReadyExceptionWhenAccessingRedisAPI(TestContext testContext) {
+        Async async = testContext.async();
+        Mockito.when(redisAPI.info(any())).thenReturn(Future.failedFuture("Boooom"));
+
+        readyProvider.ready(redisAPI).onComplete(event -> {
+            assertReadiness(testContext, event, false);
+            async.complete();
+        });
+    }
+}

src/test/resources/redis_info_persistance_loading_0

@@ -0,0 +1,31 @@
+# Persistence
+loading:0
+async_loading:0
+current_cow_peak:0
+current_cow_size:0
+current_cow_size_age:0
+current_fork_perc:0.00
+current_save_keys_processed:0
+current_save_keys_total:0
+rdb_changes_since_last_save:108
+rdb_bgsave_in_progress:0
+rdb_last_save_time:1718713249
+rdb_last_bgsave_status:ok
+rdb_last_bgsave_time_sec:0
+rdb_current_bgsave_time_sec:-1
+rdb_saves:296
+rdb_last_cow_size:0
+rdb_last_load_keys_expired:0
+rdb_last_load_keys_loaded:0
+aof_enabled:0
+aof_rewrite_in_progress:0
+aof_rewrite_scheduled:0
+aof_last_rewrite_time_sec:-1
+aof_current_rewrite_time_sec:-1
+aof_last_bgrewrite_status:ok
+aof_rewrites:0
+aof_rewrites_consecutive_failures:0
+aof_last_write_status:ok
+aof_last_cow_size:0
+module_fork_in_progress:0
+module_fork_last_cow_size:0