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Merged
merlimat merged 3 commits into from
Nov 8, 2018
Merged

Fixed race condition in schema initialization in partitioned topics #2959

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d6cae39
Fixed race condition in schema initialization in partitioned topics
merlimat Nov 8, 2018
9159d86
Removed lombok log
merlimat Nov 8, 2018
b75284b
Fixed tests
merlimat Nov 8, 2018
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244 changes: 170 additions & 74 deletions ...broker/src/main/java/org/apache/pulsar/broker/service/schema/BookkeeperSchemaStorage.java
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Original file line number Diff line number Diff line change
Expand Up @@ -53,11 +53,16 @@
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.Code;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class BookkeeperSchemaStorage implements SchemaStorage {
private static final Logger log = LoggerFactory.getLogger(BookkeeperSchemaStorage.class);

private static final String SchemaPath = "/schemas";
private static final List<ACL> Acl = ZooDefs.Ids.OPEN_ACL_UNSAFE;
private static final byte[] LedgerPassword = "".getBytes();
Expand All @@ -68,9 +73,6 @@ public class BookkeeperSchemaStorage implements SchemaStorage {
private final ServiceConfiguration config;
private BookKeeper bookKeeper;


private final ConcurrentMap<String, CompletableFuture<LocatorEntry>> locatorEntries = new ConcurrentHashMap<>();

private final ConcurrentMap<String, CompletableFuture<StoredSchema>> readSchemaOperations = new ConcurrentHashMap<>();

@VisibleForTesting
Expand Down Expand Up @@ -124,9 +126,15 @@ public CompletableFuture<SchemaVersion> delete(String key) {
private CompletableFuture<StoredSchema> getSchema(String schemaId) {
// There's already a schema read operation in progress. Just piggyback on that
return readSchemaOperations.computeIfAbsent(schemaId, key -> {
if (log.isDebugEnabled()) {
log.debug("[{}] Fetching schema from store", schemaId);
}
CompletableFuture<StoredSchema> future = new CompletableFuture<>();

getSchemaLocator(getSchemaPath(schemaId)).thenCompose(locator -> {
if (log.isDebugEnabled()) {
log.debug("[{}] Got schema locator {}", schemaId, locator);
}
if (!locator.isPresent()) {
return completedFuture(null);
}
Expand All @@ -136,6 +144,10 @@ private CompletableFuture<StoredSchema> getSchema(String schemaId) {
.thenApply(entry -> new StoredSchema(entry.getSchemaData().toByteArray(),
new LongSchemaVersion(schemaLocator.getInfo().getVersion())));
}).handleAsync((res, ex) -> {
if (log.isDebugEnabled()) {
log.debug("[{}] Get operation completed. res={} -- ex={}", schemaId, res, ex);
}

// Cleanup the pending ops from the map
readSchemaOperations.remove(schemaId, future);
if (ex != null) {
Expand Down Expand Up @@ -165,7 +177,14 @@ public void close() throws Exception {

@NotNull
private CompletableFuture<StoredSchema> getSchema(String schemaId, long version) {
if (log.isDebugEnabled()) {
log.debug("[{}] Get schema - version: {}", schemaId, version);
}

return getSchemaLocator(getSchemaPath(schemaId)).thenCompose(locator -> {
if (log.isDebugEnabled()) {
log.debug("[{}] Get schema - version: {} - locator: {}", schemaId, version, locator);
}

if (!locator.isPresent()) {
return completedFuture(null);
Expand All @@ -188,29 +207,116 @@ private CompletableFuture<StoredSchema> getSchema(String schemaId, long version)

@NotNull
private CompletableFuture<Long> putSchema(String schemaId, byte[] data, byte[] hash) {
return getOrCreateSchemaLocator(getSchemaPath(schemaId)).thenCompose(locatorEntry ->
addNewSchemaEntryToStore(locatorEntry.locator.getIndexList(), data).thenCompose(position ->
updateSchemaLocator(schemaId, locatorEntry, position, hash)
)
);
return getSchemaLocator(getSchemaPath(schemaId)).thenCompose(optLocatorEntry -> {
if (optLocatorEntry.isPresent()) {
// Schema locator was already present
return addNewSchemaEntryToStore(optLocatorEntry.get().locator.getIndexList(), data)
.thenCompose(position -> updateSchemaLocator(schemaId, optLocatorEntry.get(), position, hash));
} else {
// No schema was defined yet
CompletableFuture<Long> future = new CompletableFuture<>();
createNewSchema(schemaId, data, hash)
.thenAccept(version -> future.complete(version))
.exceptionally(ex -> {
if (ex.getCause() instanceof NodeExistsException) {
// There was a race condition on the schema creation. Since it has now been created,
// retry the whole operation so that we have a chance to recover without bubbling error
// back to producer/consumer
putSchema(schemaId, data, hash)
.thenAccept(version -> future.complete(version))
.exceptionally(ex2 -> {
future.completeExceptionally(ex2);
return null;
});
} else {
// For other errors, just fail the operation
future.completeExceptionally(ex);
}

return null;
});

return future;
}
});
}

@NotNull
private CompletableFuture<Long> putSchemaIfAbsent(String schemaId, byte[] data, byte[] hash) {
return getOrCreateSchemaLocator(getSchemaPath(schemaId)).thenCompose(locatorEntry -> {
byte[] storedHash = locatorEntry.locator.getInfo().getHash().toByteArray();
if (storedHash.length > 0 && Arrays.equals(storedHash, hash)) {
return completedFuture(locatorEntry.locator.getInfo().getVersion());
}
return findSchemaEntryByHash(locatorEntry.locator.getIndexList(), hash).thenCompose(version -> {
if (isNull(version)) {
return addNewSchemaEntryToStore(locatorEntry.locator.getIndexList(), data).thenCompose(position ->
updateSchemaLocator(schemaId, locatorEntry, position, hash)
);
} else {
return completedFuture(version);
return getSchemaLocator(getSchemaPath(schemaId)).thenCompose(optLocatorEntry -> {

if (optLocatorEntry.isPresent()) {
// Schema locator was already present
SchemaStorageFormat.SchemaLocator locator = optLocatorEntry.get().locator;
byte[] storedHash = locator.getInfo().getHash().toByteArray();
if (storedHash.length > 0 && Arrays.equals(storedHash, hash)) {
return completedFuture(locator.getInfo().getVersion());
}
});

if (log.isDebugEnabled()) {
log.debug("[{}] findSchemaEntryByHash - hash={}", schemaId, hash);
}

return findSchemaEntryByHash(locator.getIndexList(), hash).thenCompose(version -> {
if (isNull(version)) {
return addNewSchemaEntryToStore(locator.getIndexList(), data).thenCompose(
position -> updateSchemaLocator(schemaId, optLocatorEntry.get(), position, hash));
} else {
return completedFuture(version);
}
});
} else {
// No schema was defined yet
CompletableFuture<Long> future = new CompletableFuture<>();
createNewSchema(schemaId, data, hash)
.thenAccept(version -> future.complete(version))
.exceptionally(ex -> {
if (ex.getCause() instanceof NodeExistsException) {
// There was a race condition on the schema creation. Since it has now been created,
// retry the whole operation so that we have a chance to recover without bubbling error
// back to producer/consumer
putSchemaIfAbsent(schemaId, data, hash)
.thenAccept(version -> future.complete(version))
.exceptionally(ex2 -> {
future.completeExceptionally(ex2);
return null;
});
} else {
// For other errors, just fail the operation
future.completeExceptionally(ex);
}

return null;
});

return future;
}
});
}

private CompletableFuture<Long> createNewSchema(String schemaId, byte[] data, byte[] hash) {
SchemaStorageFormat.IndexEntry emptyIndex = SchemaStorageFormat.IndexEntry.newBuilder()
.setVersion(0)
.setHash(copyFrom(hash))
.setPosition(SchemaStorageFormat.PositionInfo.newBuilder()
.setEntryId(-1L)
.setLedgerId(-1L)
).build();

return addNewSchemaEntryToStore(Collections.singletonList(emptyIndex), data).thenCompose(position -> {
// The schema was stored in the ledger, now update the z-node with the pointer to it
SchemaStorageFormat.IndexEntry info = SchemaStorageFormat.IndexEntry.newBuilder()
.setVersion(0)
.setPosition(position)
.setHash(copyFrom(hash))
.build();

return createSchemaLocator(getSchemaPath(schemaId), SchemaStorageFormat.SchemaLocator.newBuilder()
.setInfo(info)
.addAllIndex(
newArrayList(info))
.build())
.thenApply(ignore -> 0L);
});
}

Expand All @@ -226,7 +332,7 @@ private CompletableFuture<Long> deleteSchema(String schemaId) {
}

@NotNull
private String getSchemaPath(String schemaId) {
private static String getSchemaPath(String schemaId) {
return SchemaPath + "/" + schemaId;
}

Expand Down Expand Up @@ -310,15 +416,23 @@ private CompletableFuture<Long> findSchemaEntryByHash(
}
}

return readSchemaEntry(index.get(0).getPosition())
.thenCompose(entry -> findSchemaEntryByHash(entry.getIndexList(), hash));
if (index.get(0).getPosition().getLedgerId() == -1) {
return completedFuture(null);
} else {
return readSchemaEntry(index.get(0).getPosition())
.thenCompose(entry -> findSchemaEntryByHash(entry.getIndexList(), hash));
}

}

@NotNull
private CompletableFuture<SchemaStorageFormat.SchemaEntry> readSchemaEntry(
SchemaStorageFormat.PositionInfo position
) {
if (log.isDebugEnabled()) {
log.debug("Reading schema entry from {}", position);
}

return openLedger(position.getLedgerId())
.thenCompose((ledger) ->
Functions.getLedgerEntry(ledger, position.getEntryId())
Expand All @@ -342,65 +456,38 @@ private CompletableFuture<Void> updateSchemaLocator(String id, SchemaStorageForm
return future;
}

@NotNull
private CompletableFuture<LocatorEntry> createSchemaLocator(String id, SchemaStorageFormat.SchemaLocator locator) {
CompletableFuture<LocatorEntry> future = new CompletableFuture<>();

ZkUtils.asyncCreateFullPathOptimistic(zooKeeper, id, locator.toByteArray(), Acl,
CreateMode.PERSISTENT, (rc, path, ctx, name) -> {
Code code = Code.get(rc);
if (code != Code.OK) {
future.completeExceptionally(KeeperException.create(code));
} else {
// Newly created z-node will have version 0
future.complete(new LocatorEntry(locator, 0));
}
}, null);

return future;
}

@NotNull
private CompletableFuture<Optional<LocatorEntry>> getSchemaLocator(String schema) {
return localZkCache.getEntryAsync(schema, new SchemaLocatorDeserializer()).thenApply(optional ->
optional.map(entry -> new LocatorEntry(entry.getKey(), entry.getValue().getVersion()))
);
}

@NotNull
private CompletableFuture<LocatorEntry> getOrCreateSchemaLocator(String schema) {
// Protect from concurrent schema locator creation
return locatorEntries.computeIfAbsent(schema, key -> {
CompletableFuture<LocatorEntry> future = new CompletableFuture<>();

getSchemaLocator(schema).thenCompose(schemaLocatorStatEntry -> {
if (schemaLocatorStatEntry.isPresent()) {
return completedFuture(schemaLocatorStatEntry.get());
} else {
SchemaStorageFormat.SchemaLocator locator = SchemaStorageFormat.SchemaLocator.newBuilder()
.setInfo(SchemaStorageFormat.IndexEntry.newBuilder().setVersion(-1L)
.setHash(ByteString.EMPTY).setPosition(SchemaStorageFormat.PositionInfo.newBuilder()
.setEntryId(-1L).setLedgerId(-1L)))
.build();

CompletableFuture<LocatorEntry> zkFuture = new CompletableFuture<>();

ZkUtils.asyncCreateFullPathOptimistic(zooKeeper, schema, locator.toByteArray(), Acl,
CreateMode.PERSISTENT, (rc, path, ctx, name) -> {
Code code = Code.get(rc);
if (code != Code.OK) {
zkFuture.completeExceptionally(KeeperException.create(code));
} else {
zkFuture.complete(new LocatorEntry(locator, -1));
}
}, null);

return zkFuture;
}
}).handleAsync((res, ex) -> {
// Cleanup the pending ops from the map
locatorEntries.remove(schema, future);
if (ex != null) {
future.completeExceptionally(ex);
} else {
future.complete(res);
}
return null;
});

return future;
});
}

@NotNull
private CompletableFuture<Long> addEntry(LedgerHandle ledgerHandle, SchemaStorageFormat.SchemaEntry entry) {
final CompletableFuture<Long> future = new CompletableFuture<>();
ledgerHandle.asyncAddEntry(entry.toByteArray(),
(rc, handle, entryId, ctx) -> {
if (rc != BKException.Code.OK) {
future.completeExceptionally(BKException.create(rc));
future.completeExceptionally(bkException("Failed to add entry", rc, ledgerHandle.getId(), -1));
} else {
future.complete(entryId);
}
Expand All @@ -420,7 +507,7 @@ private CompletableFuture<LedgerHandle> createLedger() {
LedgerPassword,
(rc, handle, ctx) -> {
if (rc != BKException.Code.OK) {
future.completeExceptionally(BKException.create(rc));
future.completeExceptionally(bkException("Failed to create ledger", rc, -1, -1));
} else {
future.complete(handle);
}
Expand All @@ -438,7 +525,7 @@ private CompletableFuture<LedgerHandle> openLedger(Long ledgerId) {
LedgerPassword,
(rc, handle, ctx) -> {
if (rc != BKException.Code.OK) {
future.completeExceptionally(BKException.create(rc));
future.completeExceptionally(bkException("Failed to open ledger", rc, ledgerId, -1));
} else {
future.complete(handle);
}
Expand All @@ -452,7 +539,7 @@ private CompletableFuture<Void> closeLedger(LedgerHandle ledgerHandle) {
CompletableFuture<Void> future = new CompletableFuture<>();
ledgerHandle.asyncClose((rc, handle, ctx) -> {
if (rc != BKException.Code.OK) {
future.completeExceptionally(BKException.create(rc));
future.completeExceptionally(bkException("Failed to close ledger", rc, ledgerHandle.getId(), -1));
} else {
future.complete(null);
}
Expand All @@ -466,7 +553,7 @@ static CompletableFuture<LedgerEntry> getLedgerEntry(LedgerHandle ledger, long e
ledger.asyncReadEntries(entry, entry,
(rc, handle, entries, ctx) -> {
if (rc != BKException.Code.OK) {
future.completeExceptionally(BKException.create(rc));
future.completeExceptionally(bkException("Failed to read entry", rc, ledger.getId(), entry));
} else {
future.complete(entries.nextElement());
}
Expand Down Expand Up @@ -519,4 +606,13 @@ static class LocatorEntry {
this.zkZnodeVersion = zkZnodeVersion;
}
}

public static Exception bkException(String operation, int rc, long ledgerId, long entryId) {
String message = org.apache.bookkeeper.client.api.BKException.getMessage(rc) + " - ledger=" + ledgerId;

if (entryId != -1) {
message += " - entry=" + entryId;
}
return new IOException(message);
}
}
4 changes: 1 addition & 3 deletions ...er/src/test/java/org/apache/pulsar/broker/service/schema/PartitionedTopicsSchemaTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -38,10 +38,8 @@ public class PartitionedTopicsSchemaTest extends BrokerBkEnsemblesTests {

/**
* Test that sequence id from a producer is correct when there are send errors
*
* the test is disabled {@link https://github.com/apache/pulsar/issues/2651}
*/
@Test(enabled = false)
@Test
public void partitionedTopicWithSchema() throws Exception {
admin.namespaces().createNamespace("prop/my-test", Collections.singleton("usc"));

Expand Down
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