rdblue commented on a change in pull request #4245: URL: https://github.com/apache/iceberg/pull/4245#discussion_r832649361
########## File path: core/src/main/java/org/apache/iceberg/rest/HTTPClient.java ########## @@ -0,0 +1,282 @@ +/* + * 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.iceberg.rest; + +import com.fasterxml.jackson.core.JsonProcessingException; +import com.fasterxml.jackson.databind.ObjectMapper; +import java.io.IOException; +import java.net.URI; +import java.util.Map; +import java.util.function.Consumer; +import org.apache.hc.client5.http.classic.methods.HttpUriRequest; +import org.apache.hc.client5.http.classic.methods.HttpUriRequestBase; +import org.apache.hc.client5.http.impl.classic.CloseableHttpClient; +import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse; +import org.apache.hc.client5.http.impl.classic.HttpClients; +import org.apache.hc.core5.http.ContentType; +import org.apache.hc.core5.http.HttpHeaders; +import org.apache.hc.core5.http.HttpStatus; +import org.apache.hc.core5.http.Method; +import org.apache.hc.core5.http.ParseException; +import org.apache.hc.core5.http.impl.EnglishReasonPhraseCatalog; +import org.apache.hc.core5.http.io.entity.EntityUtils; +import org.apache.hc.core5.http.io.entity.StringEntity; +import org.apache.hc.core5.io.CloseMode; +import org.apache.iceberg.exceptions.RESTException; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableMap; +import org.apache.iceberg.relocated.com.google.common.collect.Maps; +import org.apache.iceberg.rest.responses.ErrorResponse; +import org.apache.iceberg.rest.responses.ErrorResponseParser; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * An HttpClient for usage with the REST catalog. + */ +public class HTTPClient implements RESTClient { + + private static final Logger LOG = LoggerFactory.getLogger(HTTPClient.class); + + private final String uri; + private final CloseableHttpClient httpClient; + private final ObjectMapper mapper; + private final Map<String, String> additionalHeaders; + + private HTTPClient( + String uri, CloseableHttpClient httpClient, ObjectMapper mapper, Map<String, String> additionalHeaders) { + this.uri = uri; + this.httpClient = httpClient != null ? httpClient : HttpClients.createDefault(); + this.mapper = mapper != null ? mapper : new ObjectMapper(); + this.additionalHeaders = additionalHeaders != null ? additionalHeaders : ImmutableMap.of(); + } + + private static String extractResponseBodyAsString(CloseableHttpResponse response) { + try { + if (response.getEntity() == null) { + return null; + } + + // EntityUtils.toString returns null when HttpEntity.getContent returns null. + return EntityUtils.toString(response.getEntity(), "UTF-8"); + } catch (IOException | ParseException e) { + throw new RESTException(e, "Failed to convert HTTP response body to string"); + } + } + + // Per the spec, the only currently defined / used "success" responses are 200 and 202. + private static boolean isSuccessful(CloseableHttpResponse response) { + int code = response.getCode(); + return code == HttpStatus.SC_OK || code == HttpStatus.SC_ACCEPTED; + } + + private static ErrorResponse buildDefaultErrorResponse(CloseableHttpResponse response) { + String responseReason = response.getReasonPhrase(); + String message = + responseReason != null && !responseReason.isEmpty() ? responseReason : + EnglishReasonPhraseCatalog.INSTANCE.getReason(response.getCode(), null /* ignored */); + String type = "RESTException"; + return ErrorResponse.builder() + .responseCode(response.getCode()) + .withMessage(message) + .withType(type) + .build(); + } + + private static void handleFailure( + CloseableHttpResponse response, String responseBody, Consumer<ErrorResponse> errorHandler) { + ErrorResponse errorResponse = null; + + if (responseBody != null) { + try { + errorResponse = ErrorResponseParser.fromJson(responseBody); + } catch (Exception e) { + // It's possible to receive a non-successful response that isn't a properly defined ErrorResponse + // without any bugs in the server implementation. So we ignore this exception and build an error + // response for the user. + // + // For example, the connection could time out before every reaching the server, in which case we'll + // likely get a 5xx with the load balancers default 5xx response. + LOG.error("Failed to parse an error response. Will create one instead.", e); + } + } + + if (errorResponse == null) { + errorResponse = buildDefaultErrorResponse(response); + } + + errorHandler.accept(errorResponse); + + // Throw a RESTException, in case the provided error handler does not throw. + throw new RESTException( + "Entered the error handler path but no exception was thrown for error response %s", + ErrorResponseParser.toJson(errorResponse)); + } + + /** + * Method to execute an HTTP request and process the corresponding response. + * + * @param method - HTTP method, such as GET, POST, HEAD, etc. + * @param path - URL path to send the request to + * @param requestBody - Content to place in the request body + * @param responseType - Class of the Response type. Needs to have serializer registered with ObjectMapper + * @param errorHandler - Error handler delegated for HTTP responses which handles server error responses + * @param <T> - Class type of the response for deserialization. Must be registered with the ObjectMapper. + * @return The response entity, parsed and converted to its type T + */ + public <T> T execute( + Method method, String path, Object requestBody, Class<T> responseType, Consumer<ErrorResponse> errorHandler) { + if (path.startsWith("/")) { + throw new RESTException( + "Received a malformed path for a REST request: %s. Paths should not start with /", path); + } + + String fullUri = String.format("%s/%s", uri, path); + HttpUriRequestBase request = new HttpUriRequestBase(method.name(), URI.create(fullUri)); + addRequestHeaders(request); + + if (requestBody != null) { + try { + StringEntity stringEntity = new StringEntity(mapper.writeValueAsString(requestBody)); + request.setEntity(stringEntity); + } catch (JsonProcessingException e) { + throw new RESTException(e, "Failed to write request body: %s", requestBody); + } + } + + try (CloseableHttpResponse response = httpClient.execute(request)) { + + // Skip parsing the response stream for any successful request not expecting a response body + if (responseType == null && isSuccessful(response)) { + return null; + } + + String responseBody = responseType != null ? extractResponseBodyAsString(response) : null; + + if (!isSuccessful(response)) { + // The provided error handler is expected to throw, but a RESTException is thrown if not. + handleFailure(response, responseBody, errorHandler); Review comment: Minor: consider naming the method `throwFailure` rather than `handleFailure` so that it is obvious here that the method is guaranteed to throw an exception. -- This is an automated message from the Apache Git Service. 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