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commit 0ff7e95c21c6a2d85009cfdf4c457a3d5b9b961d Author: Hunter Lee <[email protected]> AuthorDate: Wed Jul 22 11:09:49 2020 -0700 Add HttpZkFallbackRoutingDataReader Implement an Http-ZK fallback routing data reader. ZkRoutingDataReader will follow. --- .../routing/HttpZkFallbackRoutingDataReader.java | 79 +++++++++++++++++++++- .../TestHttpZkFallbackRoutingDataReader.java | 71 ++++++++++++++++++- 2 files changed, 148 insertions(+), 2 deletions(-) diff --git a/zookeeper-api/src/main/java/org/apache/helix/zookeeper/routing/HttpZkFallbackRoutingDataReader.java b/zookeeper-api/src/main/java/org/apache/helix/zookeeper/routing/HttpZkFallbackRoutingDataReader.java index 1b4713c..add034f 100644 --- a/zookeeper-api/src/main/java/org/apache/helix/zookeeper/routing/HttpZkFallbackRoutingDataReader.java +++ b/zookeeper-api/src/main/java/org/apache/helix/zookeeper/routing/HttpZkFallbackRoutingDataReader.java @@ -1,4 +1,81 @@ package org.apache.helix.zookeeper.routing; -public class HttpZkFallbackRoutingDataReader { +/* + * 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. + */ + +import java.util.List; +import java.util.Map; + +import com.google.common.collect.ImmutableMap; +import org.apache.helix.zookeeper.constant.RoutingDataReaderType; +import org.apache.helix.zookeeper.exception.MultiZkException; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * HTTP and ZK-based RoutingDataReader that first tries an HTTP call to MSDS and upon failure, + * falls back to ZK for routing data. + * HttpZkFallbackRoutingDataReader does not maintain a ZK connection - it establishes for reading + * and closes it right away. + */ +public class HttpZkFallbackRoutingDataReader implements RoutingDataReader { + private static final Logger LOG = LoggerFactory.getLogger(HttpZkFallbackRoutingDataReader.class); + + /** + * Returns a map form of metadata store routing data. + * The map fields stand for metadata store realm address (key), and a corresponding list of ZK + * path sharding keys (key). + * @param endpoint two comma-separated endpoints. <HTTP endpoint>,<ZK address> + * @return + */ + @Override + public Map<String, List<String>> getRawRoutingData(String endpoint) { + Map<RoutingDataReaderType, String> endpointMap = parseEndpoint(endpoint); + try { + return new HttpRoutingDataReader() + .getRawRoutingData(endpointMap.get(RoutingDataReaderType.HTTP)); + } catch (MultiZkException e) { + LOG.warn( + "HttpZkFallbackRoutingDataReader::getRawRoutingData: failed to read routing data via " + + "HTTP. Falling back to ZK!", e); + // TODO: increment failure count and emit as a metric + return new ZkRoutingDataReader().getRawRoutingData(endpointMap.get(RoutingDataReaderType.ZK)); + } + } + + /** + * For a fallback routing data reader, endpoints are given in a comma-separated string in the + * fallback order. This method parses the string and returns a map of routing data source type to + * its respective endpoint. + * @param endpointString + * @return + */ + private Map<RoutingDataReaderType, String> parseEndpoint(String endpointString) { + String[] endpoints = endpointString.split(","); + if (endpoints.length != 2) { + throw new MultiZkException( + "HttpZkFallbackRoutingDataReader::parseEndpoint: endpoint string does not contain two " + + "proper comma-separated endpoints for HTTP and ZK! Endpoint string: " + + endpointString); + } + return ImmutableMap + .of(RoutingDataReaderType.HTTP, endpoints[0], RoutingDataReaderType.ZK, endpoints[1]); + } } diff --git a/zookeeper-api/src/test/java/org/apache/helix/zookeeper/routing/TestHttpZkFallbackRoutingDataReader.java b/zookeeper-api/src/test/java/org/apache/helix/zookeeper/routing/TestHttpZkFallbackRoutingDataReader.java index 85896af..d959ad2 100644 --- a/zookeeper-api/src/test/java/org/apache/helix/zookeeper/routing/TestHttpZkFallbackRoutingDataReader.java +++ b/zookeeper-api/src/test/java/org/apache/helix/zookeeper/routing/TestHttpZkFallbackRoutingDataReader.java @@ -1,4 +1,73 @@ package org.apache.helix.zookeeper.routing; -public class TestHttpZkFallbackRoutingDataReader { +/* + * 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. + */ + +import java.io.IOException; +import java.util.HashSet; +import java.util.List; +import java.util.Map; + +import org.apache.helix.msdcommon.mock.MockMetadataStoreDirectoryServer; +import org.apache.helix.zookeeper.constant.TestConstants; +import org.apache.helix.zookeeper.exception.MultiZkException; +import org.apache.helix.zookeeper.impl.ZkTestBase; +import org.testng.Assert; +import org.testng.annotations.BeforeClass; +import org.testng.annotations.Test; + + +public class TestHttpZkFallbackRoutingDataReader extends ZkTestBase { + private MockMetadataStoreDirectoryServer _msdsServer; + private static final String HOST = "localhost"; + private static final int PORT = 1992; + private static final String NAMESPACE = "TestHttpZkFallbackRoutingDataReader"; + private static final String MSDS_ENDPOINT = + "http://"; + HOST + ":" + PORT + "/admin/v2/namespaces/" + NAMESPACE; + + @BeforeClass + public void beforeClass() throws IOException { + // Start MockMSDS + _msdsServer = new MockMetadataStoreDirectoryServer(HOST, PORT, NAMESPACE, + TestConstants.FAKE_ROUTING_DATA); + _msdsServer.startServer(); + } + + @Test + public void testGetRawRoutingData() { + HttpZkFallbackRoutingDataReader reader = new HttpZkFallbackRoutingDataReader(); + + // This read should read from HTTP + String endpointString = MSDS_ENDPOINT + "," + ZK_ADDR; + Map<String, List<String>> rawRoutingData = reader.getRawRoutingData(endpointString); + TestConstants.FAKE_ROUTING_DATA.forEach((realm, keys) -> Assert + .assertEquals(new HashSet(rawRoutingData.get(realm)), new HashSet(keys))); + + // Shut down MSDS so that it would read from ZK (fallback) + _msdsServer.stopServer(); + try { + reader.getRawRoutingData(endpointString); + Assert.fail("Must encounter a MultiZkException since the path in ZK does not exist!"); + } catch (MultiZkException e) { + // Check the exception message to ensure that it's reading from ZK + Assert.assertTrue(e.getMessage() + .contains("Routing data directory ZNode /METADATA_STORE_ROUTING_DATA does not exist")); + } + } }
