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20 package org.apache.hadoop.hbase.monitoring;
21
22 import java.io.BufferedReader;
23 import java.io.File;
24 import java.io.FileInputStream;
25 import java.io.IOException;
26 import java.io.InputStreamReader;
27 import java.io.PrintWriter;
28 import java.nio.channels.FileChannel;
29 import java.util.Enumeration;
30 import java.util.Set;
31
32 import org.apache.hadoop.io.IOUtils;
33 import org.apache.log4j.Appender;
34 import org.apache.log4j.FileAppender;
35 import org.apache.log4j.Logger;
36
37 import com.google.common.collect.Sets;
38
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40
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42
43 public abstract class LogMonitoring {
44 public static Set<File> getActiveLogFiles() throws IOException {
45 Set<File> ret = Sets.newHashSet();
46 Appender a;
47 @SuppressWarnings("unchecked")
48 Enumeration<Appender> e = Logger.getRootLogger().getAllAppenders();
49 while (e.hasMoreElements()) {
50 a = e.nextElement();
51 if (a instanceof FileAppender) {
52 FileAppender fa = (FileAppender) a;
53 String filename = fa.getFile();
54 ret.add(new File(filename));
55 }
56 }
57 return ret;
58 }
59
60
61 public static void dumpTailOfLogs(
62 PrintWriter out, long tailKb) throws IOException {
63 Set<File> logs = LogMonitoring.getActiveLogFiles();
64 for (File f : logs) {
65 out.println("+++++++++++++++++++++++++++++++");
66 out.println(f.getAbsolutePath());
67 out.println("+++++++++++++++++++++++++++++++");
68 try {
69 dumpTailOfLog(f, out, tailKb);
70 } catch (IOException ioe) {
71 out.println("Unable to dump log at " + f);
72 ioe.printStackTrace(out);
73 }
74 out.println("\n\n");
75 }
76 }
77
78 private static void dumpTailOfLog(File f, PrintWriter out, long tailKb)
79 throws IOException {
80 FileInputStream fis = new FileInputStream(f);
81 try {
82 FileChannel channel = fis.getChannel();
83 channel.position(Math.max(0, channel.size() - tailKb*1024));
84 BufferedReader r = new BufferedReader(
85 new InputStreamReader(fis));
86 r.readLine();
87 String line;
88 while ((line = r.readLine()) != null) {
89 out.println(line);
90 }
91 } finally {
92 IOUtils.closeStream(fis);
93 }
94 }
95 }