SebastianGruza commented on code in PR #3221:
URL: https://github.com/apache/hugegraph/pull/3221#discussion_r4053653667
##########
hugegraph-server/hugegraph-api/src/main/java/org/apache/hugegraph/api/filter/AuthenticationFilter.java:
##########
@@ -77,6 +77,7 @@ public class AuthenticationFilter implements
ContainerRequestFilter, ContainerRe
private static final AntPathMatcher MATCHER = new AntPathMatcher();
private static final Set<String> FIXED_WHITE_API_SET = ImmutableSet.of(
"versions",
+ "readiness",
Review Comment:
Done in 4a4aa1cc, thanks, that would have been a nasty interaction: a
readiness probe shed under load would pull exactly the busiest Servers out of
the Service while the storage is healthy. `readiness` is in
`LoadDetectFilter.WHITE_API_LIST` next to `versions`; `LoadReleaseFilter` reads
the same list, so the `workLoad` counter stays balanced.
`testFilter_ReadinessIgnoredLikeVersions` in `LoadDetectFilterTest`: with a
2-thread limit and one request in flight the filter lets `/readiness` through
without touching the counter and without a log entry, in the same shape as
`testFilter_WhiteListPathIgnored`. Readiness is not meant to shed load; the
`ReadinessAPI` Javadoc says it answers from the storage state.
##########
hugegraph-server/hugegraph-hstore/src/main/java/org/apache/hugegraph/backend/store/hstore/HstoreStorageProbe.java:
##########
@@ -0,0 +1,362 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to You under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.hugegraph.backend.store.hstore;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionService;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorCompletionService;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.apache.commons.lang3.concurrent.BasicThreadFactory;
+import org.apache.hugegraph.pd.client.PDClient;
+import org.apache.hugegraph.pd.common.PDException;
+import org.apache.hugegraph.pd.grpc.Metapb;
+import org.apache.hugegraph.store.grpc.state.HgStoreStateGrpc;
+import org.apache.hugegraph.store.grpc.state.SubStateReq;
+import org.apache.hugegraph.util.E;
+import org.apache.hugegraph.util.Log;
+import org.slf4j.Logger;
+
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import io.grpc.StatusRuntimeException;
+
+/**
+ * Storage-aware readiness of this server, from this server's point of view:
+ * at least one Store answers a direct, local, read-only gRPC call
+ * (HgStoreState.getScanState, which reads the node's own scan-pool stats and
+ * never touches raft). The Store list comes from PD, refreshed in the
+ * background (single-flight) while the last known list is used right away, so
+ * PD only matters until the first list is known: a PD that is slow, restarting
+ * or down afterwards does not change the readiness of a server whose Stores
+ * still answer. Every known Store is pinged in parallel and the first answer
+ * wins; every wait is bounded by one shared time budget. The result carries
+ * no addresses and no raw exception text, since it is served without
+ * authentication; the full messages go to the log.
+ */
+public final class HstoreStorageProbe {
+
+ public static final String META_STORAGE_READINESS = "storage_readiness";
+
+ private static final Logger LOG = Log.logger(HstoreStorageProbe.class);
+
+ private static final ExecutorService EXECUTOR =
Executors.newCachedThreadPool(
+ new
BasicThreadFactory.Builder().namingPattern("storage-readiness-%d")
+ .daemon(true).build());
+
+ private static final KnownStores KNOWN = new KnownStores();
+ private static final Map<String, ManagedChannel> CHANNELS = new
ConcurrentHashMap<>();
+
+ private HstoreStorageProbe() {
+ }
+
+ /** The active stores as PD sees them. */
+ public interface StoreLister {
+
+ List<Metapb.Store> activeStores() throws Exception;
+ }
+
+ /** One cheap call to one store; returning (any value) means it answered.
*/
+ public interface StorePinger {
+
+ void ping(Metapb.Store store, long timeoutMs) throws Exception;
+ }
+
+ /** The last store list PD answered with, shared by consecutive probes. */
+ public static final class KnownStores {
+
+ private volatile List<Metapb.Store> stores = Collections.emptyList();
+ private volatile long at;
+ private volatile Boolean pdOk;
+ private volatile long pdAt;
+ private final AtomicReference<CompletableFuture<List<Metapb.Store>>>
inFlight =
+ new AtomicReference<>();
+
+ public List<Metapb.Store> stores() {
+ return this.stores;
+ }
+
+ public long ageMs() {
+ return this.at == 0L ? -1L : System.currentTimeMillis() - this.at;
+ }
+
+ /** Outcome of the last finished PD refresh, null before the first
one. */
+ public Boolean pdOk() {
+ return this.pdOk;
+ }
+
+ public long pdAgeMs() {
+ return this.pdAt == 0L ? -1L : System.currentTimeMillis() -
this.pdAt;
+ }
+
+ public void update(List<Metapb.Store> stores) {
+ this.pdOk = true;
+ this.pdAt = System.currentTimeMillis();
+ if (stores != null && !stores.isEmpty()) {
+ this.stores = Collections.unmodifiableList(new
ArrayList<>(stores));
+ this.at = this.pdAt;
+ }
+ }
+
+ public void pdFailed() {
+ this.pdOk = false;
+ this.pdAt = System.currentTimeMillis();
+ }
+
+ /**
+ * The refresh in flight, or a new one started on `executor`: only one
+ * PD call runs at a time no matter how many probes miss the cache,
+ * so a hung PD parks one thread, not one per probe.
+ */
+ CompletableFuture<List<Metapb.Store>> refresh(StoreLister lister,
+ ExecutorService
executor) {
+ CompletableFuture<List<Metapb.Store>> running =
this.inFlight.get();
+ if (running != null && !running.isDone()) {
+ return running;
+ }
+ CompletableFuture<List<Metapb.Store>> mine = new
CompletableFuture<>();
+ if (!this.inFlight.compareAndSet(running, mine)) {
+ return this.inFlight.get();
+ }
+ executor.execute(() -> {
+ try {
+ List<Metapb.Store> stores = lister.activeStores();
+ this.update(stores);
+ mine.complete(stores == null ? Collections.emptyList() :
stores);
+ } catch (Throwable e) {
+ this.pdFailed();
+ mine.completeExceptionally(e);
+ }
+ });
+ return mine;
+ }
+ }
+
+ /** The unauthenticated body: no addresses, no raw exception text. */
+ private static Map<String, Object> result(boolean ready, String reason,
int activeStores,
+ Long answeredStore, Boolean
pdReachable,
+ long pdAgeMs, long storesAgeMs,
long storeMillis) {
+ Map<String, Object> map = new LinkedHashMap<>();
+ map.put("ready", ready);
+ map.put("reason", reason);
+ map.put("active_stores", activeStores);
+ map.put("answered_store", answeredStore);
+ map.put("pd_reachable", pdReachable);
+ map.put("pd_checked_age_ms", pdAgeMs);
+ map.put("stores_age_ms", storesAgeMs);
+ map.put("store_millis", storeMillis);
+ return map;
+ }
+
+ /**
+ * Probe through the process-wide PD client and this probe's own plaintext
+ * channels to the stores (the store gRPC server takes no credentials).
+ *
+ * @param timeoutMs the whole budget for PD plus stores
+ */
+ public static Map<String, Object> probe(long timeoutMs) {
+ PDClient pd = HstoreSessionsImpl.getDefaultPdClient();
+ if (pd == null) {
+ return result(false, "pd client not initialised", 0, null, false,
-1L, -1L, 0L);
+ }
+ return probe(KNOWN, () -> {
+ List<Metapb.Store> stores = pd.getActiveStores();
+ pruneChannels(CHANNELS, stores);
+ return stores;
+ }, HstoreStorageProbe::pingScanState, timeoutMs, EXECUTOR);
+ }
+
+ /** Shut down the channels of addresses PD no longer lists (replaced
Stores). */
+ static void pruneChannels(Map<String, ManagedChannel> channels,
+ List<Metapb.Store> stores) {
+ if (stores == null) {
Review Comment:
Done in 4a4aa1cc. `pruneChannels()` returns on an empty list as well
(`stores == null || stores.isEmpty()`), the same rule `KnownStores.update()`
applies: as long as the pings use the last known list, their channels stay
open. `testChannelsOfReplacedStoresAreShutDown` now also checks that an empty
listing neither shuts down nor removes the channel of a known Store. 18/18.
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