Java tutorial
/* * Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file 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 com.amazonaws; import static com.amazonaws.SDKGlobalConfiguration.PROFILING_SYSTEM_PROPERTY; import java.net.URI; import java.net.URISyntaxException; import java.util.List; import java.util.Map.Entry; import java.util.concurrent.CopyOnWriteArrayList; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.amazonaws.auth.RegionAwareSigner; import com.amazonaws.auth.Signer; import com.amazonaws.auth.SignerFactory; import com.amazonaws.handlers.RequestHandler; import com.amazonaws.handlers.RequestHandler2; import com.amazonaws.http.AmazonHttpClient; import com.amazonaws.http.ExecutionContext; import com.amazonaws.http.HttpMethodName; import com.amazonaws.http.HttpRequest; import com.amazonaws.metrics.AwsSdkMetrics; import com.amazonaws.metrics.RequestMetricCollector; import com.amazonaws.regions.Region; import com.amazonaws.util.AWSRequestMetrics; import com.amazonaws.util.AWSRequestMetrics.Field; import com.amazonaws.util.AwsHostNameUtils; import com.amazonaws.util.Classes; /** * Abstract base class for Amazon Web Service Java clients. * <p> * Responsible for basic client capabilities that are the same across all AWS * SDK Java clients (ex: setting the client endpoint). */ public abstract class AmazonWebServiceClient { private static final String AMAZON = "Amazon"; private static final String AWS = "AWS"; public static final boolean LOGGING_AWS_REQUEST_METRIC = true; private static final Log log = LogFactory.getLog(AmazonWebServiceClient.class); /** * The service endpoint to which this client will send requests. * <p> * Subclass should only read but not assign to this field, at least not * without synchronization on the enclosing object for thread-safety * reason. */ protected volatile URI endpoint; /** * Used to explicitly override the internal signer region computed by the * default implementation. This field is typically null. */ private volatile String signerRegionOverride; /** The client configuration */ protected ClientConfiguration clientConfiguration; /** Low level client for sending requests to AWS services. */ protected AmazonHttpClient client; /** Optional request handlers for additional request processing. */ protected final List<RequestHandler2> requestHandler2s; /** Optional offset (in seconds) to use when signing requests */ protected int timeOffset; /** AWS signer for authenticating requests. */ private volatile Signer signer; /** * The cached service abbreviation for this service, used for identifying * service endpoints by region, identifying the necessary signer, etc. * Thread safe so it's backward compatible. */ private volatile String serviceName; /** * Constructs a new AmazonWebServiceClient object using the specified * configuration. * * @param clientConfiguration * The client configuration for this client. */ public AmazonWebServiceClient(ClientConfiguration clientConfiguration) { this(clientConfiguration, null); } /** * Constructs a new AmazonWebServiceClient object using the specified * configuration and request metric collector. * * @param clientConfiguration * The client configuration for this client. * @param requestMetricCollector * optional request metric collector to be used at the http * client level; can be null. */ public AmazonWebServiceClient(ClientConfiguration clientConfiguration, RequestMetricCollector requestMetricCollector) { this.clientConfiguration = clientConfiguration; client = new AmazonHttpClient(clientConfiguration, requestMetricCollector); requestHandler2s = new CopyOnWriteArrayList<RequestHandler2>(); } /** * Returns the signer. * <p> * Note, however, the signer configured for S3 is incomplete at this stage * as the information on the S3 bucket and key is not yet known. */ protected Signer getSigner() { return signer; } /** * Overrides the default endpoint for this client. Callers can use this * method to control which AWS region they want to work with. * <p> * <b>This method is not threadsafe. Endpoints should be configured when the * client is created and before any service requests are made. Changing it * afterwards creates inevitable race conditions for any service requests in * transit.</b> * <p> * Callers can pass in just the endpoint (ex: "ec2.amazonaws.com") or a full * URL, including the protocol (ex: "https://ec2.amazonaws.com"). If the * protocol is not specified here, the default protocol from this client's * {@link ClientConfiguration} will be used, which by default is HTTPS. * <p> * For more information on using AWS regions with the AWS SDK for Java, and * a complete list of all available endpoints for all AWS services, see: * <a href="http://developer.amazonwebservices.com/connect/entry.jspa?externalID=3912"> * http://developer.amazonwebservices.com/connect/entry.jspa?externalID=3912</a> * * @param endpoint * The endpoint (ex: "ec2.amazonaws.com") or a full URL, * including the protocol (ex: "https://ec2.amazonaws.com") of * the region specific AWS endpoint this client will communicate * with. * @throws IllegalArgumentException * If any problems are detected with the specified endpoint. */ public void setEndpoint(String endpoint) throws IllegalArgumentException { URI uri = toURI(endpoint); Signer signer = computeSignerByURI(uri, signerRegionOverride, false); synchronized (this) { this.endpoint = uri; this.signer = signer; } } /** Returns the endpoint as a URI. */ private URI toURI(String endpoint) throws IllegalArgumentException { /* * If the endpoint doesn't explicitly specify a protocol to use, then * we'll defer to the default protocol specified in the client * configuration. */ if (endpoint.contains("://") == false) { endpoint = clientConfiguration.getProtocol().toString() + "://" + endpoint; } try { return new URI(endpoint); } catch (URISyntaxException e) { throw new IllegalArgumentException(e); } } /** * An internal method that is not expected to be normally * called except for AWS internal development purposes. * <p> * Overrides the default endpoint for this client * ("http://dynamodb.us-east-1.amazonaws.com/") and explicitly provides an * AWS region ID and AWS service name to use when the client calculates a * signature for requests. In almost all cases, this region ID and service * name are automatically determined from the endpoint, and callers should * use the simpler one-argument form of setEndpoint instead of this method. * <p> * Callers can pass in just the endpoint (ex: * "dynamodb.us-east-1.amazonaws.com/") or a full URL, including the * protocol (ex: "http://dynamodb.us-east-1.amazonaws.com/"). If the * protocol is not specified here, the default protocol from this client's * {@link ClientConfiguration} will be used, which by default is HTTPS. * <p> * For more information on using AWS regions with the AWS SDK for Java, and * a complete list of all available endpoints for all AWS services, see: <a * href= * "http://developer.amazonwebservices.com/connect/entry.jspa?externalID=3912" * > http://developer.amazonwebservices.com/connect/entry.jspa?externalID= * 3912</a> * * @param endpoint * The endpoint (ex: "dynamodb.us-east-1.amazonaws.com/") or a * full URL, including the protocol (ex: * "http://dynamodb.us-east-1.amazonaws.com/") of the region * specific AWS endpoint this client will communicate with. * @param serviceName * This parameter is ignored. * @param regionId * The ID of the region in which this service resides AND the * overriding region for signing purposes. * * @throws IllegalArgumentException * If any problems are detected with the specified endpoint. * @deprecated */ @Deprecated public void setEndpoint(String endpoint, String serviceName, String regionId) { URI uri = toURI(endpoint); Signer signer = computeSignerByServiceRegion(serviceName, regionId, regionId, true); synchronized (this) { this.signer = signer; this.endpoint = uri; this.signerRegionOverride = regionId; } } /** * @deprecated this method is now a no-op, as overriding the signer from * sublcass is no longer supported. */ @Deprecated protected void configSigner(URI uri) { } /** * @deprecated this method is now a no-op, as overriding the signer from * sublcass is no longer supported. */ @Deprecated protected void configSigner(String serviceName, String regionId) { } /** * Returns the signer based on the given URI and the current AWS client * configuration. Currently only the SQS client can have different region on * a per request basis. For other AWS clients, the region remains the same * on a per AWS client level. * <p> * Note, however, the signer returned for S3 is incomplete at this stage as * the information on the S3 bucket and key is not yet known. */ public Signer getSignerByURI(URI uri) { return computeSignerByURI(uri, signerRegionOverride, true); } /** * Returns the signer for the given uri and the current client * configuration. * <p> * Note, however, the signer returned for S3 is incomplete at this stage as * the information on the S3 bucket and key is not yet known. * * @param signerRegionOverride * the overriding signer region; or null if there is none. * @param isRegionIdAsSignerParam * true if the "regionId" is used to configure the signer if * applicable; false if this method is called for the purpose of * purely setting the communication end point of this AWS client, * and therefore the "regionId" parameter will not be used * directly for configuring the signer. */ private Signer computeSignerByURI(URI uri, String signerRegionOverride, boolean isRegionIdAsSignerParam) { if (uri == null) { throw new IllegalArgumentException( "Endpoint is not set. Use setEndpoint to set an endpoint before performing any request."); } String service = getServiceNameIntern(); String region = AwsHostNameUtils.parseRegionName(uri.getHost(), service); return computeSignerByServiceRegion(service, region, signerRegionOverride, isRegionIdAsSignerParam); } /** * Returns the signer for the given service name, region id, and the current * client configuration. * <p> * Note, however, the signer returned for S3 is incomplete at this stage as * the information on the S3 bucket and key is not yet known. * * @param regionId * the region for sending AWS requests * @param signerRegionOverride * the overriding signer region; or null if there is none. * @param isRegionIdAsSignerParam * true if the "regionId" is used to configure the signer if * applicable; false if this method is called for the purpose of * purely setting the communication end point of this AWS client, * and therefore the "regionId" parameter will not be used * directly for configuring the signer. */ private Signer computeSignerByServiceRegion(String serviceName, String regionId, String signerRegionOverride, boolean isRegionIdAsSignerParam) { String signerType = clientConfiguration.getSignerOverride(); Signer signer = signerType == null ? SignerFactory.getSigner(serviceName, regionId) : SignerFactory.getSignerByTypeAndService(signerType, serviceName); if (signer instanceof RegionAwareSigner) { // Overrides the default region computed RegionAwareSigner regionAwareSigner = (RegionAwareSigner) signer; // (signerRegionOverride != null) means that it is likely to be AWS // internal dev work, as "signerRegionOverride" is typically null // when used in the external release if (signerRegionOverride != null) regionAwareSigner.setRegionName(signerRegionOverride); else if (regionId != null && isRegionIdAsSignerParam) regionAwareSigner.setRegionName(regionId); } return signer; } /** * An alternative to {@link AmazonWebServiceClient#setEndpoint(String)}, sets the * regional endpoint for this client's service calls. Callers can use this * method to control which AWS region they want to work with. * <p> * <b>This method is not threadsafe. A region should be configured when the * client is created and before any service requests are made. Changing it * afterwards creates inevitable race conditions for any service requests in * transit or retrying.</b> * <p> * By default, all service endpoints in all regions use the https protocol. * To use http instead, specify it in the {@link ClientConfiguration} * supplied at construction. * * @param region * The region this client will communicate with. See * {@link Region#getRegion(com.amazonaws.regions.Regions)} for * accessing a given region. * @throws java.lang.IllegalArgumentException * If the given region is null, or if this service isn't * available in the given region. See * {@link Region#isServiceSupported(String)} * @see Region#getRegion(com.amazonaws.regions.Regions) * @see Region#createClient(Class, com.amazonaws.auth.AWSCredentialsProvider, ClientConfiguration) */ public void setRegion(Region region) throws IllegalArgumentException { if (region == null) { throw new IllegalArgumentException("No region provided"); } String serviceName = getServiceNameIntern(); String serviceEndpoint; if (region.isServiceSupported(serviceName)) { serviceEndpoint = region.getServiceEndpoint(serviceName); int protocolIdx = serviceEndpoint.indexOf("://"); // Strip off the protocol to allow the client config to specify it if (protocolIdx >= 0) { serviceEndpoint = serviceEndpoint.substring(protocolIdx + "://".length()); } } else { serviceEndpoint = String.format("%s.%s.%s", serviceName, region.getName(), region.getDomain()); log.info("{" + serviceName + ", " + region.getName() + "} was not " + "found in region metadata, trying to construct an " + "endpoint using the standard pattern for this region: '" + serviceEndpoint + "'."); } URI uri = toURI(serviceEndpoint); Signer signer = computeSignerByServiceRegion(serviceName, region.getName(), signerRegionOverride, false); synchronized (this) { this.endpoint = uri; this.signer = signer; } } /** * @deprecated by client configuration via the constructor. * This method will be removed later on. */ @Deprecated public void setConfiguration(ClientConfiguration clientConfiguration) { AmazonHttpClient existingClient = this.client; RequestMetricCollector requestMetricCollector = null; if (existingClient != null) { requestMetricCollector = existingClient.getRequestMetricCollector(); existingClient.shutdown(); } this.clientConfiguration = clientConfiguration; this.client = new AmazonHttpClient(clientConfiguration, requestMetricCollector); } /** * Shuts down this client object, releasing any resources that might be held * open. This is an optional method, and callers are not expected to call * it, but can if they want to explicitly release any open resources. Once a * client has been shutdown, it should not be used to make any more * requests. */ public void shutdown() { client.shutdown(); } /** * Converts a Request<T> object into an HttpRequest object. Copies all the * headers, parameters, etc. from the Request into the new HttpRequest. * * @param request * The request to convert. * @param methodName * The HTTP method (GET, PUT, DELETE, HEAD) to use in the * converted HttpRequest object. * * @return A new HttpRequest object created from the details of the * specified Request<T> object. */ @Deprecated protected <T> HttpRequest convertToHttpRequest(Request<T> request, HttpMethodName methodName) { HttpRequest httpRequest = new HttpRequest(methodName); for (Entry<String, String> parameter : request.getParameters().entrySet()) { httpRequest.addParameter(parameter.getKey(), parameter.getValue()); } for (Entry<String, String> parameter : request.getHeaders().entrySet()) { httpRequest.addHeader(parameter.getKey(), parameter.getValue()); } httpRequest.setServiceName(request.getServiceName()); httpRequest.setEndpoint(request.getEndpoint()); httpRequest.setResourcePath(request.getResourcePath()); httpRequest.setOriginalRequest(request.getOriginalRequest()); return httpRequest; } /** * @deprecated by {@link #addRequestHandler(RequestHandler2)}. * * Appends a request handler to the list of registered handlers that are run * as part of a request's lifecycle. * * @param requestHandler * The new handler to add to the current list of request * handlers. */ @Deprecated public void addRequestHandler(RequestHandler requestHandler) { requestHandler2s.add(RequestHandler2.adapt(requestHandler)); } /** * Appends a request handler to the list of registered handlers that are run * as part of a request's lifecycle. * * @param requestHandler2 * The new handler to add to the current list of request * handlers. */ public void addRequestHandler(RequestHandler2 requestHandler2) { requestHandler2s.add(requestHandler2); } /** * Removes a request handler from the list of registered handlers that are run * as part of a request's lifecycle. * * @param requestHandler * The handler to remove from the current list of request * handlers. */ public void removeRequestHandler(RequestHandler requestHandler) { requestHandler2s.remove(RequestHandler2.adapt(requestHandler)); } public void removeRequestHandler(RequestHandler2 requestHandler2) { requestHandler2s.remove(requestHandler2); } protected ExecutionContext createExecutionContext(AmazonWebServiceRequest req) { boolean isMetricsEnabled = isRequestMetricsEnabled(req) || isProfilingEnabled(); return new ExecutionContext(requestHandler2s, isMetricsEnabled, this); } protected final ExecutionContext createExecutionContext(Request<?> req) { return createExecutionContext(req.getOriginalRequest()); } /** * @deprecated by {@link #createExecutionContext(AmazonWebServiceRequest)}. * * This method exists only for backward compatiblity reason, so * that clients compiled against the older version of this class * won't get {@link NoSuchMethodError} at runtime. However, * calling this methods would effectively ignore and disable the * request metric collector, if any, specified at the request * level. Request metric collector specified at the service * client or AWS SDK level will still be honored. */ @Deprecated protected final ExecutionContext createExecutionContext() { boolean isMetricsEnabled = isRMCEnabledAtClientOrSdkLevel() || isProfilingEnabled(); return new ExecutionContext(requestHandler2s, isMetricsEnabled, this); } /* Check the profiling system property and return true if set */ protected static boolean isProfilingEnabled() { return System.getProperty(PROFILING_SYSTEM_PROPERTY) != null; } /** * Returns true if request metric collection is applicable to the given * request; false otherwise. */ protected final boolean isRequestMetricsEnabled(AmazonWebServiceRequest req) { RequestMetricCollector c = req.getRequestMetricCollector(); // request level collector if (c != null && c.isEnabled()) { return true; } return isRMCEnabledAtClientOrSdkLevel(); } /** * Returns true if request metric collection is enabled at the service * client or AWS SDK level request; false otherwise. */ private boolean isRMCEnabledAtClientOrSdkLevel() { RequestMetricCollector c = requestMetricCollector(); return c != null && c.isEnabled(); } /** * Sets the optional value for time offset for this client. This * value will be applied to all requests processed through this client. * Value is in seconds, positive values imply the current clock is "fast", * negative values imply clock is slow. * * @param timeOffset * The optional value for time offset (in seconds) for this client. */ public void setTimeOffset(int timeOffset) { this.timeOffset = timeOffset; } /** * Sets the optional value for time offset for this client. This * value will be applied to all requests processed through this client. * Value is in seconds, positive values imply the current clock is "fast", * negative values imply clock is slow. * * @param timeOffset * The optional value for time offset (in seconds) for this client. * * @return the updated web service client */ public AmazonWebServiceClient withTimeOffset(int timeOffset) { setTimeOffset(timeOffset); return this; } /** * Returns the optional value for time offset for this client. This * value will be applied to all requests processed through this client. * Value is in seconds, positive values imply the current clock is "fast", * negative values imply clock is slow. * * @return The optional value for time offset (in seconds) for this client. */ public int getTimeOffset() { return timeOffset; } /** * Returns the client specific {@link RequestMetricCollector}; or null if * there is none. */ public RequestMetricCollector getRequestMetricsCollector() { return client.getRequestMetricCollector(); } /** * Returns the client specific request metric collector if there is one; or * the one at the AWS SDK level otherwise. */ protected RequestMetricCollector requestMetricCollector() { RequestMetricCollector mc = client.getRequestMetricCollector(); return mc == null ? AwsSdkMetrics.getRequestMetricCollector() : mc; } /** * Returns the most specific request metric collector, starting from the * request level, then client level, then finally the AWS SDK level. */ protected final RequestMetricCollector findRequestMetricCollector(Request<?> req) { AmazonWebServiceRequest origReq = req.getOriginalRequest(); RequestMetricCollector mc = origReq.getRequestMetricCollector(); if (mc != null) { return mc; } mc = getRequestMetricsCollector(); return mc == null ? AwsSdkMetrics.getRequestMetricCollector() : mc; } /** * Convenient method to end the client execution without logging the * awsRequestMetrics. */ protected final void endClientExecution(AWSRequestMetrics awsRequestMetrics, Request<?> request, Response<?> response) { this.endClientExecution(awsRequestMetrics, request, response, !LOGGING_AWS_REQUEST_METRIC); } /** * Common routine to end a client AWS request/response execution and collect * the request metrics. Caller of this routine is responsible for starting * the event for {@link Field#ClientExecuteTime} and call this method * in a try-finally block. * * @param loggingAwsRequestMetrics true to log the awsRequestMetrics; false otherwise. */ protected final void endClientExecution(AWSRequestMetrics awsRequestMetrics, Request<?> request, Response<?> response, boolean loggingAwsRequestMetrics) { if (request != null) { awsRequestMetrics.endEvent(Field.ClientExecuteTime); awsRequestMetrics.getTimingInfo().endTiming(); RequestMetricCollector c = findRequestMetricCollector(request); c.collectMetrics(request, response); } if (loggingAwsRequestMetrics) awsRequestMetrics.log(); } /** * @deprecated by {@link #getServiceName()}. */ @Deprecated protected String getServiceAbbreviation() { return getServiceNameIntern(); } /** * Returns the service abbreviation for this service, used for identifying * service endpoints by region, identifying the necessary signer, etc. * Used to be call "getServiceAbbreviation". */ public String getServiceName() { return getServiceNameIntern(); } /** * Internal method for implementing {@link #getServiceName()}. Method is * protected by intent so peculiar subclass that don't follow the class * naming convention can choose to return whatever service name as needed. */ protected String getServiceNameIntern() { if (serviceName == null) { synchronized (this) { if (serviceName == null) { return serviceName = computeServiceName(); } } } return serviceName; } /** * An internal method used to explicitly override the service name * computed by the default implementation. This method is not expected to be * normally called except for AWS internal development purposes. */ public final void setServiceNameIntern(String serviceName) { this.serviceName = serviceName; } /** * Returns the service name of this AWS http client by first looking it up * from the SDK internal configuration, and if not found, derive it from the * class name of the immediate subclass of {@link AmazonWebServiceClient}. * No configuration is necessary if the simple class name of the http client * follows the convention of <code>(Amazon|AWS).*(JavaClient|Client)</code>. */ private String computeServiceName() { Class<?> httpClientClass = Classes.childClassOf(AmazonWebServiceClient.class, this); final String httpClientName = httpClientClass.getSimpleName(); String service = ServiceNameFactory.getServiceName(httpClientName); if (service != null) { return service; // only if it is so explicitly configured } // Otherwise, make use of convention over configuration int j = httpClientName.indexOf("JavaClient"); if (j == -1) { j = httpClientName.indexOf("Client"); if (j == -1) { throw new IllegalStateException( "Unrecognized suffix for the AWS http client class name " + httpClientName); } } int i = httpClientName.indexOf(AMAZON); int len; if (i == -1) { i = httpClientName.indexOf(AWS); if (i == -1) { throw new IllegalStateException( "Unrecognized prefix for the AWS http client class name " + httpClientName); } len = AWS.length(); } else { len = AMAZON.length(); } if (i >= j) { throw new IllegalStateException("Unrecognized AWS http client class name " + httpClientName); } String serviceName = httpClientName.substring(i + len, j); return serviceName.toLowerCase(); } /** * Returns the signer region override. * * @see #setSignerRegionOverride(String). */ public final String getSignerRegionOverride() { return signerRegionOverride; } /** * An internal method used to explicitly override the internal signer region * computed by the default implementation. This method is not expected to be * normally called except for AWS internal development purposes. */ public final void setSignerRegionOverride(String signerRegionOverride) { Signer signer = computeSignerByURI(endpoint, signerRegionOverride, true); synchronized (this) { this.signer = signer; this.signerRegionOverride = signerRegionOverride; } } }