rdblue commented on a change in pull request #4245: URL: https://github.com/apache/iceberg/pull/4245#discussion_r835964354
########## File path: core/src/main/java/org/apache/iceberg/rest/HTTPClient.java ########## @@ -0,0 +1,283 @@ +/* + * 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.io.UncheckedIOException; +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(); + } + + // Process a failed response through the provided errorHandler, and throw a RESTException if the + // provided error handler doesn't already throw. + private static void throwFailure( + CloseableHttpResponse response, String responseBody, Consumer<ErrorResponse> errorHandler) { + ErrorResponse errorResponse = null; + + if (responseBody != null) { + try { + errorResponse = ErrorResponseParser.fromJson(responseBody); + } catch (UncheckedIOException | IllegalArgumentException 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 an exception in case the provided error handler does not throw. + throw new RESTException("Unhandled error: %s", 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 + */ + private <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 = extractResponseBodyAsString(response); + + if (!isSuccessful(response)) { + // The provided error handler is expected to throw, but a RESTException is thrown if not. + throwFailure(response, responseBody, errorHandler); + } + + if (responseBody == null) { + throw new RESTException( + "Invalid (null) response body for request (expected %s): method=%s, path=%s, status=%d", + responseType.getSimpleName(), method.name(), path, response.getCode()); + } + + try { + return mapper.readValue(responseBody, responseType); + } catch (JsonProcessingException e) { + throw new RESTException( + "Received a success response code of %d, but failed to parse response body into %s", + response.getCode(), responseType.getSimpleName()); + } + } catch (IOException e) { + throw new RESTException(e, "Error occurred while processing %s request", method); + } + } + + @Override + public void head(String path, Consumer<ErrorResponse> errorHandler) { + execute(Method.HEAD, path, null, null, errorHandler); + } + + @Override + public <T> T get(String path, Class<T> responseType, Consumer<ErrorResponse> errorHandler) { + return execute(Method.GET, path, null, responseType, errorHandler); + } + + @Override + public <T> T post(String path, Object body, Class<T> responseType, Consumer<ErrorResponse> errorHandler) { + return execute(Method.POST, path, body, responseType, errorHandler); + } + + @Override + public <T> T delete(String path, Class<T> responseType, Consumer<ErrorResponse> errorHandler) { + return execute(Method.DELETE, path, null, responseType, errorHandler); + } + + private void addRequestHeaders(HttpUriRequest request) { + request.setHeader(HttpHeaders.ACCEPT, ContentType.APPLICATION_JSON.getMimeType()); + // Many systems require that content type is set regardless and will fail, even on an empty bodied request. + request.setHeader(HttpHeaders.CONTENT_TYPE, ContentType.APPLICATION_JSON.getMimeType()); + additionalHeaders.forEach(request::setHeader); + } + + @Override + public void close() throws IOException { + httpClient.close(CloseMode.GRACEFUL); + } + + public static Builder builder() { + return new Builder(); + } + + public static class Builder { + private final Map<String, String> additionalHeaders = Maps.newHashMap(); + private String uri; + private CloseableHttpClient httpClient; + private ObjectMapper mapper; + + private Builder() { + } + + private static String asBearer(String token) { + return String.format("Bearer %s", token); + } + + public Builder uri(String baseUri) { + Preconditions.checkNotNull(baseUri, "Invalid uri for http client: null"); + this.uri = RESTUtil.stripTrailingSlash(baseUri); + return this; + } + + // Visible for testing + public Builder httpClient(CloseableHttpClient client) { + this.httpClient = client; + return this; + } + + public Builder mapper(ObjectMapper objectMapper) { Review comment: I think this should also be visible for testing only. The class should use one configured with all of the rest serializers by default and not expose serialization to the caller. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
