yifan-c commented on code in PR #45: URL: https://github.com/apache/cassandra-sidecar/pull/45#discussion_r1192861006
########## client/src/main/java/org/apache/cassandra/sidecar/client/exception/UnexpectedStatusCodeException.java: ########## @@ -0,0 +1,53 @@ +/* + * 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.cassandra.sidecar.client.exception; + +/** + * Represents an exception raised when an unexpected status code is encountered + */ +public class UnexpectedStatusCodeException extends RuntimeException +{ + /** + * Constructs a new {@link UnexpectedStatusCodeException} with the given {@code statusCode} and {@code body} + * + * @param statusCode the response status code + * @param body the body of the response + */ + public UnexpectedStatusCodeException(int statusCode, String body) Review Comment: Is it safe to assume the body is always `String`? ########## client/src/main/java/org/apache/cassandra/sidecar/client/selection/OrderedInstanceSelectionPolicy.java: ########## @@ -0,0 +1,54 @@ +/* + * 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.cassandra.sidecar.client.selection; + +import java.util.Iterator; + +import org.apache.cassandra.sidecar.client.SidecarInstance; +import org.apache.cassandra.sidecar.client.SidecarInstancesProvider; +import org.jetbrains.annotations.NotNull; + +/** + * A selection policy for a multiple Cassandra Sidecar instances where the iterator returns in order + */ +public class OrderedInstanceSelectionPolicy implements InstanceSelectionPolicy +{ + protected final SidecarInstancesProvider instancesProvider; + + /** + * Constructs a new {@link OrderedInstanceSelectionPolicy} with the provided list of instances + * + * @param instancesProvider the class that provides the sidecar instances + */ + public OrderedInstanceSelectionPolicy(SidecarInstancesProvider instancesProvider) + { + this.instancesProvider = instancesProvider; + } + + /** + * Returns an iterator of {@link SidecarInstance instances}. + * + * @return an iterator of {@link SidecarInstance instances} + */ + @NotNull + public Iterator<SidecarInstance> iterator() + { + return instancesProvider.instances().iterator(); Review Comment: The order depends in the value returned from `instancesProvider.instances()`, which is implementation dependent. For example, the provider could shuffle the instances and return. In this example, the `OrderedInstanceSelectionPolicy` is no different from `RandomInstanceSelectionPolicy`. nit: It might want to sort the instances, so the order is guaranteed. ########## client/src/main/java/org/apache/cassandra/sidecar/client/retry/ExponentialBackoffRetryPolicy.java: ########## @@ -0,0 +1,90 @@ +/* + * 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.cassandra.sidecar.client.retry; + +/** + * A retry policy that will perform an exponential backoff. The backoff period increases for each retry attempt. + * + * <p>Example: For a configured {@code maxRetries} of {@code 10}, {@code retryDelayMillis} of {@code 200} + * milliseconds, and {@code maxRetryDelayMillis} of {@code 20,000} milliseconds, the sequence is as follows: + * + * <pre> + * request backoff + * + * 1 200 + * 2 400 + * 3 800 + * 4 1600 + * 5 3200 + * 6 6400 + * 7 12800 + * 8 20000 + * 9 20000 + * 10 20000 + * </pre> + */ +public class ExponentialBackoffRetryPolicy extends BasicRetryPolicy +{ + private final long maxRetryDelayMillis; + + /** + * Constructs an exponential backoff retry policy unlimited number of retries and no delay between retries. + */ + public ExponentialBackoffRetryPolicy() + { + super(); + this.maxRetryDelayMillis = 0; + } + + /** + * Constructs an exponential backoff retry policy with {@code maxRetries} number of retries, + * {@code retryDelayMillis} delay between retries, and {@code maxRetryDelayMillis} maximum delay for the + * exponential backoff. + * + * @param maxRetries the maximum number of retries + * @param retryDelayMillis the delay between retries in milliseconds + * @param maxRetryDelayMillis the maximum retry delay in milliseconds + */ + public ExponentialBackoffRetryPolicy(int maxRetries, long retryDelayMillis, long maxRetryDelayMillis) + { + super(maxRetries, retryDelayMillis); + this.maxRetryDelayMillis = maxRetryDelayMillis; + } + + /** + * Returns the number of milliseconds to wait before attempting the next request. This value is upper-bounded + * by {@code maxRetryDelayMillis} if configured. The delay increases exponentially based on the number of + * attempts already performed. + * + * @param attempts the number of attempts already performed for this request + * @return the number of milliseconds to wait before attempting the next request + */ + @Override + protected long retryDelayMillis(int attempts) + { + long exponentialValue = (long) Math.pow(2, attempts - 1); + // do not multiply times retryDelayMillis, if we've reached the Long.MAX_VALUE already to avoid overflows + long retryDelay = exponentialValue == Long.MAX_VALUE ? exponentialValue : exponentialValue * retryDelayMillis; Review Comment: `exponentialValue * retryDelayMillis` could overflow and result in a negative value. But it will never happen in practice, no human could possibly wait for this long time. ########## client/src/main/java/org/apache/cassandra/sidecar/client/request/Request.java: ########## @@ -0,0 +1,95 @@ +/* + * 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.cassandra.sidecar.client.request; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; + +import io.netty.handler.codec.http.HttpHeaderNames; +import io.netty.handler.codec.http.HttpMethod; +import org.apache.cassandra.sidecar.common.utils.HttpRange; + +/** + * An abstract class representing a request for Sidecar + */ +public abstract class Request +{ + protected final String requestURI; + + /** + * Constructs a Sidecar request with the given {@code requestURI}. Defaults to {@code ssl} enabled. + * + * @param requestURI the URI of the request + */ + protected Request(String requestURI) + { + this.requestURI = requestURI; + } + + /** + * @return a map of headers for the request + */ + public Map<String, String> headers() + { + HttpRange range = range(); + if (range == null) + { + return Collections.emptyMap(); + } + Map<String, String> headers = new HashMap<>(); + headers.put(HttpHeaderNames.RANGE.toString(), range.toString()); + return Collections.unmodifiableMap(headers); + } + + /** + * @return the range for the HTTP request + */ + protected HttpRange range() + { + return null; + } + + /** + * @return the HTTP method to be used for the request + */ + public HttpMethod method() + { + return HttpMethod.GET; Review Comment: nit: it would read more clear to not supply a default HttpMethod, and enforce the subclasses to define it. ########## client/src/main/java/org/apache/cassandra/sidecar/client/retry/BasicRetryPolicy.java: ########## @@ -0,0 +1,297 @@ +/* + * 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.cassandra.sidecar.client.retry; + +import java.util.List; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.TimeUnit; + +import io.netty.handler.codec.http.HttpResponseStatus; +import io.netty.handler.codec.http.HttpStatusClass; +import org.apache.cassandra.sidecar.client.HttpResponse; +import org.apache.cassandra.sidecar.client.exception.ResourceNotFoundException; +import org.apache.cassandra.sidecar.client.request.Request; + +/** + * A basic {@link RetryPolicy} supporting standard status codes + */ +public class BasicRetryPolicy extends RetryPolicy +{ + protected static final String RETRY_AFTER = "Retry-After"; + // Use -1 to retry indefinitely Review Comment: nit: define a constants -- This is an automated message from the Apache Git Service. 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