org.elasticsearch.rest.RestController Maven / Gradle / Ivy
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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.rest;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.message.ParameterizedMessage;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.client.node.NodeClient;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.Strings;
import org.elasticsearch.common.breaker.CircuitBreaker;
import org.elasticsearch.common.bytes.BytesArray;
import org.elasticsearch.common.io.stream.BytesStreamOutput;
import org.elasticsearch.common.logging.DeprecationLogger;
import org.elasticsearch.common.path.PathTrie;
import org.elasticsearch.common.util.concurrent.ThreadContext;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.core.internal.io.Streams;
import org.elasticsearch.http.HttpServerTransport;
import org.elasticsearch.indices.breaker.CircuitBreakerService;
import org.elasticsearch.usage.UsageService;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Supplier;
import java.util.function.UnaryOperator;
import java.util.stream.Collectors;
import static org.elasticsearch.rest.BytesRestResponse.TEXT_CONTENT_TYPE;
import static org.elasticsearch.rest.RestStatus.BAD_REQUEST;
import static org.elasticsearch.rest.RestStatus.INTERNAL_SERVER_ERROR;
import static org.elasticsearch.rest.RestStatus.METHOD_NOT_ALLOWED;
import static org.elasticsearch.rest.RestStatus.NOT_ACCEPTABLE;
import static org.elasticsearch.rest.RestStatus.OK;
public class RestController implements HttpServerTransport.Dispatcher {
private static final Logger logger = LogManager.getLogger(RestController.class);
private final PathTrie handlers = new PathTrie<>(RestUtils.REST_DECODER);
private final UnaryOperator handlerWrapper;
private final NodeClient client;
private final CircuitBreakerService circuitBreakerService;
/** Rest headers that are copied to internal requests made during a rest request. */
private final Set headersToCopy;
private final UsageService usageService;
public RestController(Set headersToCopy, UnaryOperator handlerWrapper,
NodeClient client, CircuitBreakerService circuitBreakerService, UsageService usageService) {
this.headersToCopy = headersToCopy;
this.usageService = usageService;
if (handlerWrapper == null) {
handlerWrapper = h -> h; // passthrough if no wrapper set
}
this.handlerWrapper = handlerWrapper;
this.client = client;
this.circuitBreakerService = circuitBreakerService;
}
/**
* Registers a REST handler to be executed when the provided {@code method} and {@code path} match the request.
*
* @param method GET, POST, etc.
* @param path Path to handle (e.g., "/{index}/{type}/_bulk")
* @param handler The handler to actually execute
* @param deprecationMessage The message to log and send as a header in the response
* @param logger The existing deprecation logger to use
*/
public void registerAsDeprecatedHandler(RestRequest.Method method, String path, RestHandler handler,
String deprecationMessage, DeprecationLogger logger) {
assert (handler instanceof DeprecationRestHandler) == false;
registerHandler(method, path, new DeprecationRestHandler(handler, deprecationMessage, logger));
}
/**
* Registers a REST handler to be executed when the provided {@code method} and {@code path} match the request, or when provided
* with {@code deprecatedMethod} and {@code deprecatedPath}. Expected usage:
*
* // remove deprecation in next major release
* controller.registerWithDeprecatedHandler(POST, "/_forcemerge", this,
* POST, "/_optimize", deprecationLogger);
* controller.registerWithDeprecatedHandler(POST, "/{index}/_forcemerge", this,
* POST, "/{index}/_optimize", deprecationLogger);
*
*
* The registered REST handler ({@code method} with {@code path}) is a normal REST handler that is not deprecated and it is
* replacing the deprecated REST handler ({@code deprecatedMethod} with {@code deprecatedPath}) that is using the same
* {@code handler}.
*
* Deprecated REST handlers without a direct replacement should be deprecated directly using {@link #registerAsDeprecatedHandler}
* and a specific message.
*
* @param method GET, POST, etc.
* @param path Path to handle (e.g., "/_forcemerge")
* @param handler The handler to actually execute
* @param deprecatedMethod GET, POST, etc.
* @param deprecatedPath Deprecated path to handle (e.g., "/_optimize")
* @param logger The existing deprecation logger to use
*/
public void registerWithDeprecatedHandler(RestRequest.Method method, String path, RestHandler handler,
RestRequest.Method deprecatedMethod, String deprecatedPath,
DeprecationLogger logger) {
// e.g., [POST /_optimize] is deprecated! Use [POST /_forcemerge] instead.
final String deprecationMessage =
"[" + deprecatedMethod.name() + " " + deprecatedPath + "] is deprecated! Use [" + method.name() + " " + path + "] instead.";
registerHandler(method, path, handler);
registerAsDeprecatedHandler(deprecatedMethod, deprecatedPath, handler, deprecationMessage, logger);
}
/**
* Registers a REST handler to be executed when one of the provided methods and path match the request.
*
* @param path Path to handle (e.g., "/{index}/{type}/_bulk")
* @param handler The handler to actually execute
* @param method GET, POST, etc.
*/
public void registerHandler(RestRequest.Method method, String path, RestHandler handler) {
if (handler instanceof BaseRestHandler) {
usageService.addRestHandler((BaseRestHandler) handler);
}
final RestHandler maybeWrappedHandler = handlerWrapper.apply(handler);
handlers.insertOrUpdate(path, new MethodHandlers(path, maybeWrappedHandler, method),
(mHandlers, newMHandler) -> mHandlers.addMethods(maybeWrappedHandler, method));
}
@Override
public void dispatchRequest(RestRequest request, RestChannel channel, ThreadContext threadContext) {
if (request.rawPath().equals("/favicon.ico")) {
handleFavicon(request.method(), request.uri(), channel);
return;
}
try {
tryAllHandlers(request, channel, threadContext);
} catch (Exception e) {
try {
channel.sendResponse(new BytesRestResponse(channel, e));
} catch (Exception inner) {
inner.addSuppressed(e);
logger.error(() ->
new ParameterizedMessage("failed to send failure response for uri [{}]", request.uri()), inner);
}
}
}
@Override
public void dispatchBadRequest(final RestChannel channel, final ThreadContext threadContext, final Throwable cause) {
try {
final Exception e;
if (cause == null) {
e = new ElasticsearchException("unknown cause");
} else if (cause instanceof Exception) {
e = (Exception) cause;
} else {
e = new ElasticsearchException(cause);
}
channel.sendResponse(new BytesRestResponse(channel, BAD_REQUEST, e));
} catch (final IOException e) {
if (cause != null) {
e.addSuppressed(cause);
}
logger.warn("failed to send bad request response", e);
channel.sendResponse(new BytesRestResponse(INTERNAL_SERVER_ERROR, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
}
}
private void dispatchRequest(RestRequest request, RestChannel channel, RestHandler handler) throws Exception {
final int contentLength = request.content().length();
if (contentLength > 0) {
final XContentType xContentType = request.getXContentType();
if (xContentType == null) {
sendContentTypeErrorMessage(request.getAllHeaderValues("Content-Type"), channel);
return;
}
if (handler.supportsContentStream() && xContentType != XContentType.JSON && xContentType != XContentType.SMILE) {
channel.sendResponse(BytesRestResponse.createSimpleErrorResponse(channel, RestStatus.NOT_ACCEPTABLE,
"Content-Type [" + xContentType + "] does not support stream parsing. Use JSON or SMILE instead"));
return;
}
}
RestChannel responseChannel = channel;
try {
if (handler.canTripCircuitBreaker()) {
inFlightRequestsBreaker(circuitBreakerService).addEstimateBytesAndMaybeBreak(contentLength, "");
} else {
inFlightRequestsBreaker(circuitBreakerService).addWithoutBreaking(contentLength);
}
// iff we could reserve bytes for the request we need to send the response also over this channel
responseChannel = new ResourceHandlingHttpChannel(channel, circuitBreakerService, contentLength);
// TODO: Count requests double in the circuit breaker if they need copying?
if (handler.allowsUnsafeBuffers() == false) {
request.ensureSafeBuffers();
}
handler.handleRequest(request, responseChannel, client);
} catch (Exception e) {
responseChannel.sendResponse(new BytesRestResponse(responseChannel, e));
}
}
private boolean handleNoHandlerFound(String rawPath, RestRequest.Method method, String uri, RestChannel channel) {
// Get the map of matching handlers for a request, for the full set of HTTP methods.
final Set validMethodSet = getValidHandlerMethodSet(rawPath);
if (validMethodSet.contains(method) == false) {
if (method == RestRequest.Method.OPTIONS) {
handleOptionsRequest(channel, validMethodSet);
return true;
}
if (validMethodSet.isEmpty() == false) {
// If an alternative handler for an explicit path is registered to a
// different HTTP method than the one supplied - return a 405 Method
// Not Allowed error.
handleUnsupportedHttpMethod(uri, method, channel, validMethodSet, null);
return true;
}
}
return false;
}
private void sendContentTypeErrorMessage(@Nullable List contentTypeHeader, RestChannel channel) throws IOException {
final String errorMessage;
if (contentTypeHeader == null) {
errorMessage = "Content-Type header is missing";
} else {
errorMessage = "Content-Type header [" +
Strings.collectionToCommaDelimitedString(contentTypeHeader) + "] is not supported";
}
channel.sendResponse(BytesRestResponse.createSimpleErrorResponse(channel, NOT_ACCEPTABLE, errorMessage));
}
private void tryAllHandlers(final RestRequest request, final RestChannel channel, final ThreadContext threadContext) throws Exception {
for (final RestHeaderDefinition restHeader : headersToCopy) {
final String name = restHeader.getName();
final List headerValues = request.getAllHeaderValues(name);
if (headerValues != null && headerValues.isEmpty() == false) {
final List distinctHeaderValues = headerValues.stream().distinct().collect(Collectors.toList());
if (restHeader.isMultiValueAllowed() == false && distinctHeaderValues.size() > 1) {
channel.sendResponse(
BytesRestResponse.
createSimpleErrorResponse(channel, BAD_REQUEST, "multiple values for single-valued header [" + name + "]."));
return;
} else {
threadContext.putHeader(name, String.join(",", distinctHeaderValues));
}
}
}
// error_trace cannot be used when we disable detailed errors
// we consume the error_trace parameter first to ensure that it is always consumed
if (request.paramAsBoolean("error_trace", false) && channel.detailedErrorsEnabled() == false) {
channel.sendResponse(
BytesRestResponse.createSimpleErrorResponse(channel, BAD_REQUEST, "error traces in responses are disabled."));
return;
}
final String rawPath = request.rawPath();
final String uri = request.uri();
final RestRequest.Method requestMethod;
try {
// Resolves the HTTP method and fails if the method is invalid
requestMethod = request.method();
// Loop through all possible handlers, attempting to dispatch the request
Iterator allHandlers = getAllHandlers(request.params(), rawPath);
while (allHandlers.hasNext()) {
final RestHandler handler;
final MethodHandlers handlers = allHandlers.next();
if (handlers == null) {
handler = null;
} else {
handler = handlers.getHandler(requestMethod);
}
if (handler == null) {
if (handleNoHandlerFound(rawPath, requestMethod, uri, channel)) {
return;
}
} else {
dispatchRequest(request, channel, handler);
return;
}
}
} catch (final IllegalArgumentException e) {
handleUnsupportedHttpMethod(uri, null, channel, getValidHandlerMethodSet(rawPath), e);
return;
}
// If request has not been handled, fallback to a bad request error.
handleBadRequest(uri, requestMethod, channel);
}
Iterator getAllHandlers(@Nullable Map requestParamsRef, String rawPath) {
final Supplier> paramsSupplier;
if (requestParamsRef == null) {
paramsSupplier = () -> null;
} else {
// Between retrieving the correct path, we need to reset the parameters,
// otherwise parameters are parsed out of the URI that aren't actually handled.
final Map originalParams = new HashMap<>(requestParamsRef);
paramsSupplier = () -> {
// PathTrie modifies the request, so reset the params between each iteration
requestParamsRef.clear();
requestParamsRef.putAll(originalParams);
return requestParamsRef;
};
}
// we use rawPath since we don't want to decode it while processing the path resolution
// so we can handle things like:
// my_index/my_type/http%3A%2F%2Fwww.google.com
return handlers.retrieveAll(rawPath, paramsSupplier);
}
/**
* Handle requests to a valid REST endpoint using an unsupported HTTP
* method. A 405 HTTP response code is returned, and the response 'Allow'
* header includes a list of valid HTTP methods for the endpoint (see
* HTTP/1.1 -
* 10.4.6 - 405 Method Not Allowed).
*/
private void handleUnsupportedHttpMethod(String uri,
@Nullable RestRequest.Method method,
final RestChannel channel,
final Set validMethodSet,
@Nullable final IllegalArgumentException exception) {
try {
final StringBuilder msg = new StringBuilder();
if (exception == null) {
msg.append("Incorrect HTTP method for uri [").append(uri);
msg.append("] and method [").append(method).append("]");
} else {
msg.append(exception.getMessage());
}
if (validMethodSet.isEmpty() == false) {
msg.append(", allowed: ").append(validMethodSet);
}
BytesRestResponse bytesRestResponse = BytesRestResponse.createSimpleErrorResponse(channel, METHOD_NOT_ALLOWED, msg.toString());
if (validMethodSet.isEmpty() == false) {
bytesRestResponse.addHeader("Allow", Strings.collectionToDelimitedString(validMethodSet, ","));
}
channel.sendResponse(bytesRestResponse);
} catch (final IOException e) {
logger.warn("failed to send bad request response", e);
channel.sendResponse(new BytesRestResponse(INTERNAL_SERVER_ERROR, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
}
}
/**
* Handle HTTP OPTIONS requests to a valid REST endpoint. A 200 HTTP
* response code is returned, and the response 'Allow' header includes a
* list of valid HTTP methods for the endpoint (see
* HTTP/1.1 - 9.2
* - Options).
*/
private void handleOptionsRequest(RestChannel channel, Set validMethodSet) {
BytesRestResponse bytesRestResponse = new BytesRestResponse(OK, TEXT_CONTENT_TYPE, BytesArray.EMPTY);
// When we have an OPTIONS HTTP request and no valid handlers, simply send OK by default (with the Access Control Origin header
// which gets automatically added).
if (validMethodSet.isEmpty() == false) {
bytesRestResponse.addHeader("Allow", Strings.collectionToDelimitedString(validMethodSet, ","));
}
channel.sendResponse(bytesRestResponse);
}
/**
* Handle a requests with no candidate handlers (return a 400 Bad Request
* error).
*/
private void handleBadRequest(String uri, RestRequest.Method method, RestChannel channel) throws IOException {
try (XContentBuilder builder = channel.newErrorBuilder()) {
builder.startObject();
{
builder.field("error", "no handler found for uri [" + uri + "] and method [" + method + "]");
}
builder.endObject();
channel.sendResponse(new BytesRestResponse(BAD_REQUEST, builder));
}
}
/**
* Get the valid set of HTTP methods for a REST request.
*/
private Set getValidHandlerMethodSet(String rawPath) {
Set validMethods = new HashSet<>();
Iterator allHandlers = getAllHandlers(null, rawPath);
while (allHandlers.hasNext()) {
final MethodHandlers methodHandlers = allHandlers.next();
if (methodHandlers != null) {
validMethods.addAll(methodHandlers.getValidMethods());
}
}
return validMethods;
}
private void handleFavicon(RestRequest.Method method, String uri, final RestChannel channel) {
try {
if (method != RestRequest.Method.GET) {
handleUnsupportedHttpMethod(uri, method, channel, Collections.singleton(RestRequest.Method.GET), null);
} else {
try {
try (InputStream stream = getClass().getResourceAsStream("/config/favicon.ico")) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
Streams.copy(stream, out);
BytesRestResponse restResponse = new BytesRestResponse(RestStatus.OK, "image/x-icon", out.toByteArray());
channel.sendResponse(restResponse);
}
} catch (IOException e) {
channel.sendResponse(
new BytesRestResponse(INTERNAL_SERVER_ERROR, BytesRestResponse.TEXT_CONTENT_TYPE, BytesArray.EMPTY));
}
}
} catch (final IllegalArgumentException e) {
handleUnsupportedHttpMethod(uri, null, channel, Collections.singleton(RestRequest.Method.GET), e);
}
}
private static final class ResourceHandlingHttpChannel implements RestChannel {
private final RestChannel delegate;
private final CircuitBreakerService circuitBreakerService;
private final int contentLength;
private final AtomicBoolean closed = new AtomicBoolean();
ResourceHandlingHttpChannel(RestChannel delegate, CircuitBreakerService circuitBreakerService, int contentLength) {
this.delegate = delegate;
this.circuitBreakerService = circuitBreakerService;
this.contentLength = contentLength;
}
@Override
public XContentBuilder newBuilder() throws IOException {
return delegate.newBuilder();
}
@Override
public XContentBuilder newErrorBuilder() throws IOException {
return delegate.newErrorBuilder();
}
@Override
public XContentBuilder newBuilder(@Nullable XContentType xContentType, boolean useFiltering) throws IOException {
return delegate.newBuilder(xContentType, useFiltering);
}
@Override
public XContentBuilder newBuilder(XContentType xContentType, XContentType responseContentType, boolean useFiltering)
throws IOException {
return delegate.newBuilder(xContentType, responseContentType, useFiltering);
}
@Override
public BytesStreamOutput bytesOutput() {
return delegate.bytesOutput();
}
@Override
public RestRequest request() {
return delegate.request();
}
@Override
public boolean detailedErrorsEnabled() {
return delegate.detailedErrorsEnabled();
}
@Override
public void sendResponse(RestResponse response) {
close();
delegate.sendResponse(response);
}
private void close() {
// attempt to close once atomically
if (closed.compareAndSet(false, true) == false) {
throw new IllegalStateException("Channel is already closed");
}
inFlightRequestsBreaker(circuitBreakerService).addWithoutBreaking(-contentLength);
}
}
private static CircuitBreaker inFlightRequestsBreaker(CircuitBreakerService circuitBreakerService) {
// We always obtain a fresh breaker to reflect changes to the breaker configuration.
return circuitBreakerService.getBreaker(CircuitBreaker.IN_FLIGHT_REQUESTS);
}
}