Java tutorial
/* * Copyright 2011-2012 Amazon Technologies, Inc. * * Licensed 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://aws.amazon.com/apache2.0 * * 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.eclipse.core.regions; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.RandomAccessFile; import java.net.MalformedURLException; import java.net.URL; import java.util.Date; import java.util.LinkedList; import java.util.List; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.eclipse.core.runtime.IPath; import org.eclipse.core.runtime.Platform; import org.eclipse.core.runtime.Status; import org.eclipse.jface.preference.IPreferenceStore; import org.eclipse.jface.resource.ImageDescriptor; import org.eclipse.ui.statushandlers.StatusManager; import com.amazonaws.eclipse.core.AWSClientFactory; import com.amazonaws.eclipse.core.AwsToolkitCore; import com.amazonaws.eclipse.core.HttpClientFactory; import com.amazonaws.eclipse.core.preferences.PreferenceConstants; import com.amazonaws.services.s3.AmazonS3; import com.amazonaws.services.s3.model.GetObjectRequest; import com.amazonaws.services.s3.model.ObjectMetadata; /** * Utilities for working with regions. */ public class RegionUtils { private static final String CLOUDFRONT_DISTRO = "http://vstoolkit.amazonwebservices.com/"; private static final String REGIONS_FILE_OVERRIDE = RegionUtils.class.getName() + ".fileOverride"; private static final String REGIONS_METADATA_S3_BUCKET = "aws-vs-toolkit"; private static final String REGIONS_METADATA_S3_OBJECT = "ServiceEndPoints.xml"; private static final String LOCAL_REGION_FILE = "/etc/regions.xml"; private static List<Region> regions; /** * Returns true if the specified service is available in the current/active * region, otherwise returns false. * * @param serviceAbbreviation * The abbreviation of the service to check. * @return True if the specified service is available in the current/active * region, otherwise returns false. * @see ServiceAbbreviations */ public static boolean isServiceSupportedInCurrentRegion(String serviceAbbreviation) { return getCurrentRegion().isServiceSupported(serviceAbbreviation); } /** * Returns a list of the available AWS regions. */ public synchronized static List<Region> getRegions() { if (regions == null) { init(); } return regions; } /** * Add a service endpoint to the special "local" region, causing the * service to show up in the AWS Explorer when the region is set to local * and setting the port that the local service is expected to listen on. */ public synchronized static void addLocalService(final String serviceName, final String serviceId, final int port) { Region local = getRegion("local"); if (local == null) { throw new IllegalStateException("No local region found!"); } Service service = new Service(serviceName, serviceId, "http://localhost:" + port, null); local.getServicesByName().put(serviceName, service); local.getServiceEndpoints().put(serviceName, service.getEndpoint()); } /** * Returns a list of the regions that support the service given. * * @see ServiceAbbreviations */ public synchronized static List<Region> getRegionsForService(String serviceAbbreviation) { List<Region> regions = new LinkedList<Region>(); for (Region r : getRegions()) { if (r.isServiceSupported(serviceAbbreviation)) { regions.add(r); } } return regions; } /** * Returns the region with the id given, if it exists. Otherwise, returns null. */ public static Region getRegion(String regionId) { for (Region r : getRegions()) { if (r.getId().equals(regionId)) { return r; } } return null; } /** * Returns the default/active region that the user previously selected. */ public static Region getCurrentRegion() { IPreferenceStore preferenceStore = AwsToolkitCore.getDefault().getPreferenceStore(); String defaultRegion = preferenceStore.getString(PreferenceConstants.P_DEFAULT_REGION); Region rval = getRegion(defaultRegion); if (rval == null) { throw new RuntimeException("Unable to determine default region"); } return rval; } /** * Searches through the defined services in all regions looking for a * service running on the specified endpoint. * * @param endpoint * The endpoint of the desired service. * @return The service running on the specified endpoint. * * @throws IllegalArgumentException * if no service is found with the specified endpoint. */ public static Service getServiceByEndpoint(String endpoint) { for (Region region : regions) { for (Service service : region.getServicesByName().values()) { if (service.getEndpoint().equals(endpoint)) { return service; } } } throw new IllegalArgumentException("Unknown service endpoint: " + endpoint); } /** * Searches through all known regions to find one with any service at the * specified endpoint. If no region is found with a service at that * endpoint, an exception is thrown. * * @param endpoint * The endpoint for any service residing in the desired region. * @return The region containing any service running at the specified * endpoint, otherwise an exception is thrown if no region is found * with a service at the specified endpoint. */ public static Region getRegionByEndpoint(String endpoint) { URL targetEndpointUrl = null; try { targetEndpointUrl = new URL(endpoint); } catch (MalformedURLException e) { throw new RuntimeException("Unable to parse service endpoint: " + e.getMessage()); } String targetHost = targetEndpointUrl.getHost(); for (Region region : getRegions()) { for (String serviceEndpoint : region.getServiceEndpoints().values()) { try { URL serviceEndpointUrl = new URL(serviceEndpoint); if (serviceEndpointUrl.getHost().equals(targetHost)) { return region; } } catch (MalformedURLException e) { Status status = new Status(Status.ERROR, AwsToolkitCore.PLUGIN_ID, "Unable to parse service endpoint: " + serviceEndpoint, e); StatusManager.getManager().handle(status, StatusManager.LOG); } } } throw new RuntimeException("No region found with any service for endpoint " + endpoint); } /** * Fetches the most recent version of the regions file from the remote * source and caches it to the workspace metadata directory, then * initializes the static list of regions with it. */ public static synchronized void init() { if (System.getProperty(REGIONS_FILE_OVERRIDE) != null) { loadRegionsFromOverrideFile(); } else { IPath stateLocation = Platform.getStateLocation(AwsToolkitCore.getDefault().getBundle()); File regionsDir = new File(stateLocation.toFile(), "regions"); File regionsFile = new File(regionsDir, "regions.xml"); cacheRegionsFile(regionsFile); initCachedRegions(regionsFile); } // Fall back onto the version we ship with the toolkit if (regions == null) { initBundledRegions(); } // If the preference store references an unknown starting region, // go ahead and set the starting region to any existing region IPreferenceStore preferenceStore = AwsToolkitCore.getDefault().getPreferenceStore(); Region defaultRegion = getRegion(preferenceStore.getString(PreferenceConstants.P_DEFAULT_REGION)); if (defaultRegion == null) { preferenceStore.setValue(PreferenceConstants.P_DEFAULT_REGION, regions.get(0).getId()); } } private static void loadRegionsFromOverrideFile() { try { System.setProperty("com.amazonaws.sdk.disableCertChecking", "true"); File regionsFile = new File(System.getProperty(REGIONS_FILE_OVERRIDE)); InputStream override = new FileInputStream(regionsFile); regions = parseRegionMetadata(override); try { cacheFlags(regionsFile.getParentFile()); } catch (Exception e) { AwsToolkitCore.getDefault().logException("Couldn't cache flag icons", e); } } catch (Exception e) { AwsToolkitCore.getDefault().logException("Couldn't load regions override", e); } } /** * Caches the regions file stored in cloudfront to the destination file * given. Tries S3 if cloudfront is unavailable. * * If the file in s3 is older than the one on disk, does nothing. */ private static void cacheRegionsFile(File regionsFile) { Date regionsFileLastModified = new Date(0); if (!regionsFile.exists()) { regionsFile.getParentFile().mkdirs(); } else { regionsFileLastModified = new Date(regionsFile.lastModified()); } try { AmazonS3 s3 = AWSClientFactory.getAnonymousS3Client(); ObjectMetadata objectMetadata = s3.getObjectMetadata(REGIONS_METADATA_S3_BUCKET, REGIONS_METADATA_S3_OBJECT); if (objectMetadata.getLastModified().after(regionsFileLastModified)) { cacheRegionsFile(regionsFile, s3); } } catch (Exception e) { AwsToolkitCore.getDefault().logException("Failed to cache regions file", e); } } /** * Tries to initialize the regions list from the file given. If the file * doesn't exist or cannot, it is deleted so that it can be fetched cleanly * on the next startup. */ private static void initCachedRegions(File regionsFile) { try { InputStream inputStream = new FileInputStream(regionsFile); regions = parseRegionMetadata(inputStream); try { cacheFlags(regionsFile.getParentFile()); } catch (Exception e) { AwsToolkitCore.getDefault().logException("Couldn't cache flag icons", e); } } catch (Exception e) { AwsToolkitCore.getDefault().logException("Couldn't read regions file", e); // Clear out the regions file so that it will get cached again at // next startup regionsFile.delete(); } } /** * Failsafe method to initialize the regions list from the list bundled with * the plugin, in case it cannot be fetched from the remote source. */ private static void initBundledRegions() { ClassLoader classLoader = RegionUtils.class.getClassLoader(); InputStream inputStream = classLoader.getResourceAsStream(LOCAL_REGION_FILE); regions = parseRegionMetadata(inputStream); for (Region r : regions) { if (r == LocalRegion.INSTANCE) { // No flag to load for the local region. continue; } AwsToolkitCore.getDefault().getImageRegistry().put(AwsToolkitCore.IMAGE_FLAG_PREFIX + r.getId(), ImageDescriptor.createFromFile(RegionUtils.class, "/icons/" + r.getFlagIconPath())); } } private static final RegionMetadataParser PARSER = new RegionMetadataParser(); /** * Parses a list of regions from the given input stream. Adds in the * special "local" region. */ private static List<Region> parseRegionMetadata(InputStream inputStream) { List<Region> list = PARSER.parseRegionMetadata(inputStream); list.add(LocalRegion.INSTANCE); return list; } /** * Caches the regions file to the location given */ private static void cacheRegionsFile(File regionsFile, AmazonS3 s3) { try { truncateFile(regionsFile); s3.getObject(new GetObjectRequest(REGIONS_METADATA_S3_BUCKET, REGIONS_METADATA_S3_OBJECT), regionsFile); } catch (Exception s3Exception) { AwsToolkitCore.getDefault().logException("Couldn't fetch regions file from s3", s3Exception); } } /** * Set the length of the file given to 0 bytes. */ private static void truncateFile(File file) throws FileNotFoundException, IOException { if (file.exists()) { RandomAccessFile raf = new RandomAccessFile(file, "rw"); raf.getChannel().truncate(0); raf.close(); } } /** * Caches flag icons as necessary, also registering images for them */ private static void cacheFlags(File regionsDir) throws ClientProtocolException, IOException { if (!regionsDir.exists()) { return; } for (Region r : regions) { if (r == LocalRegion.INSTANCE) { // Local region has no flag to initialize. continue; } File icon = new File(regionsDir, r.getFlagIconPath()); if (icon.exists() == false) { icon.getParentFile().mkdirs(); String iconUrl = CLOUDFRONT_DISTRO + r.getFlagIconPath(); fetchFile(iconUrl, icon); } AwsToolkitCore.getDefault().getImageRegistry().put(AwsToolkitCore.IMAGE_FLAG_PREFIX + r.getId(), ImageDescriptor.createFromURL(icon.getAbsoluteFile().toURI().toURL())); } } /** * Fetches a file from the URL given and writes it to the destination given. */ private static void fetchFile(String url, File destinationFile) throws IOException, ClientProtocolException, FileNotFoundException { HttpClient httpclient = HttpClientFactory.create(AwsToolkitCore.getDefault(), url); HttpGet httpget = new HttpGet(url); HttpResponse response = httpclient.execute(httpget); HttpEntity entity = response.getEntity(); if (entity != null) { InputStream instream = entity.getContent(); FileOutputStream output = new FileOutputStream(destinationFile); try { int l; byte[] tmp = new byte[2048]; while ((l = instream.read(tmp)) != -1) { output.write(tmp, 0, l); } } finally { output.close(); instream.close(); } } } /** * Load regions from remote S3 bucket. */ public static List<Region> loadRegionsFromS3() { AmazonS3 s3 = AWSClientFactory.getAnonymousS3Client(); InputStream inputStream = s3.getObject(REGIONS_METADATA_S3_BUCKET, REGIONS_METADATA_S3_OBJECT) .getObjectContent(); return parseRegionMetadata(inputStream); } /** * Load regions from local file. */ public static List<Region> loadRegionsFromLocalFile() { ClassLoader classLoader = RegionUtils.class.getClassLoader(); InputStream inputStream = classLoader.getResourceAsStream(LOCAL_REGION_FILE); return parseRegionMetadata(inputStream); } }