Java tutorial
/* * 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.htrace.impl; import com.fasterxml.jackson.annotation.JsonIgnoreProperties; import com.fasterxml.jackson.annotation.JsonProperty; import com.fasterxml.jackson.databind.ObjectMapper; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.ServerSocket; import java.net.Socket; import java.net.URI; import java.nio.file.Paths; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.htrace.core.MilliSpan; import org.apache.htrace.core.Span; import org.apache.htrace.core.SpanId; import org.eclipse.jetty.client.HttpClient; import org.eclipse.jetty.client.api.ContentResponse; import org.eclipse.jetty.http.HttpStatus; import org.junit.Assert; /** * To get instance of HTraced up and running, create an instance of this class. * Upon successful construction, htraced is running using <code>dataDir</code> as directory to * host data (leveldbs and logs). */ class HTracedProcess extends Process { private static final Log LOG = LogFactory.getLog(HTracedProcess.class); static class Builder { String host = "localhost"; Builder() { } Builder host(String host) { this.host = host; return this; } HTracedProcess build() throws Exception { return new HTracedProcess(this); } } /** * Path to the htraced binary. */ private final File htracedPath; /** * Temporary directory for test files. */ private final DataDir dataDir; /** * The Java Process object for htraced. */ private final Process delegate; /** * The HTTP host:port returned from htraced. */ private final String httpAddr; /** * The HRPC host:port returned from htraced. */ private final String hrpcAddr; /** * REST client to use to talk to htraced. */ private final HttpClient httpClient; /** * Data send back from the HTraced process on the notification port. */ @JsonIgnoreProperties(ignoreUnknown = true) public static class StartupNotificationData { /** * The hostname:port pair which the HTraced process uses for HTTP requests. */ @JsonProperty("HttpAddr") String httpAddr; /** * The hostname:port pair which the HTraced process uses for HRPC requests. */ @JsonProperty("HrpcAddr") String hrpcAddr; /** * The process ID of the HTraced process. */ @JsonProperty("ProcessId") long processId; } private HTracedProcess(Builder builder) throws Exception { this.htracedPath = Paths.get("target", "..", "go", "build", "htraced").toFile(); if (!this.htracedPath.exists()) { throw new RuntimeException("No htraced binary exists at " + this.htracedPath); } this.dataDir = new DataDir(); // Create a notifier socket bound to a random port. ServerSocket listener = new ServerSocket(0); boolean success = false; Process process = null; HttpClient http = null; try { // Use a random port for the web address. No 'scheme' yet. String random = builder.host + ":0"; String logPath = new File(dataDir.get(), "log.txt").getAbsolutePath(); // Pass cmdline args to htraced to it uses our test dir for data. ProcessBuilder pb = new ProcessBuilder(htracedPath.getAbsolutePath(), "-Dlog.level=TRACE", "-Dlog.path=" + logPath, "-Dweb.address=" + random, "-Dhrpc.address=" + random, "-Ddata.store.clear=true", "-Dstartup.notification.address=localhost:" + listener.getLocalPort(), "-Ddata.store.directories=" + dataDir.get().getAbsolutePath()); // Set HTRACED_CONF_DIR to the temporary directory we just created, to // ensure that it doesn't pull in any other configuration file that might // be on this test machine. Map<String, String> env = pb.environment(); env.put("HTRACED_CONF_DIR", dataDir.get().getAbsolutePath()); // Remove any HTRACED_WEB_DIR variable that might be set, to ensure that // we use the default value (which finds the local web files by relative // path). env.remove("HTRACED_WEB_DIR"); pb.redirectErrorStream(true); // Inherit STDERR/STDOUT i/o; dumps on console for now. Can add logs later. pb.inheritIO(); pb.directory(dataDir.get()); //assert pb.redirectInput() == Redirect.PIPE; //assert pb.redirectOutput().file() == dataDir; process = pb.start(); assert process.getInputStream().read() == -1; StartupNotificationData data = readStartupNotification(listener); httpAddr = data.httpAddr; hrpcAddr = data.hrpcAddr; LOG.info("Started htraced process " + data.processId + " with http " + "address " + data.httpAddr + ", logging to " + logPath); http = RestBufferManager.createHttpClient(60000L, 60000L); http.start(); success = true; } finally { if (!success) { // Clean up after failure if (process != null) { process.destroy(); process = null; } if (http != null) { http.stop(); } } delegate = process; listener.close(); httpClient = http; } } private static StartupNotificationData readStartupNotification(ServerSocket listener) throws IOException { Socket socket = listener.accept(); try { InputStream in = socket.getInputStream(); ObjectMapper objectMapper = new ObjectMapper(); StartupNotificationData data = objectMapper.readValue(in, StartupNotificationData.class); return data; } finally { socket.close(); } } public int hashCode() { return delegate.hashCode(); } public OutputStream getOutputStream() { throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT"); } public InputStream getInputStream() { throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT"); } public boolean equals(Object obj) { return delegate.equals(obj); } public InputStream getErrorStream() { throw new UnsupportedOperationException("Unsupported until complaint; output on STDOUT"); } public int waitFor() throws InterruptedException { return delegate.waitFor(); } public int exitValue() { return delegate.exitValue(); } public void destroy() { try { httpClient.stop(); } catch (Exception e) { LOG.error("Error stopping httpClient", e); } delegate.destroy(); try { dataDir.close(); } catch (Exception e) { LOG.error("Error closing " + dataDir, e); } LOG.trace("Destroyed htraced process."); } public String toString() { return delegate.toString(); } public String getHttpAddr() { return httpAddr; } public String getHrpcAddr() { return hrpcAddr; } /** * Ugly but how else to do file-math? * @param topLevel Presumes top-level of the htrace checkout. * @return Path to the htraced binary. */ public static File getPathToHTraceBinaryFromTopLevel(final File topLevel) { return new File(new File(new File(new File(topLevel, "htrace-htraced"), "go"), "build"), "htraced"); } public String getServerVersionJson() throws Exception { ContentResponse response = httpClient.GET(new URI(String.format("http://%s/server/version", httpAddr))); Assert.assertEquals("application/json", response.getMediaType()); Assert.assertEquals(HttpStatus.OK_200, response.getStatus()); return response.getContentAsString(); } public Span getSpan(SpanId spanId) throws Exception { ContentResponse response = httpClient .GET(new URI(String.format("http://%s/span/%s", httpAddr, spanId.toString()))); Assert.assertEquals("application/json", response.getMediaType()); String responseJson = response.getContentAsString().trim(); if (responseJson.isEmpty()) { return null; } return MilliSpan.fromJson(responseJson); } }