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19 package org.apache.hadoop.hbase.monitoring;
20
21 import java.io.BufferedReader;
22 import java.io.File;
23 import java.io.FileInputStream;
24 import java.io.IOException;
25 import java.io.InputStreamReader;
26 import java.io.PrintWriter;
27 import java.nio.channels.FileChannel;
28 import java.util.Enumeration;
29 import java.util.Set;
30
31 import org.apache.hadoop.hbase.classification.InterfaceAudience;
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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42
43 @InterfaceAudience.Private
44 public abstract class LogMonitoring {
45 public static Set<File> getActiveLogFiles() throws IOException {
46 Set<File> ret = Sets.newHashSet();
47 Appender a;
48 @SuppressWarnings("unchecked")
49 Enumeration<Appender> e = Logger.getRootLogger().getAllAppenders();
50 while (e.hasMoreElements()) {
51 a = e.nextElement();
52 if (a instanceof FileAppender) {
53 FileAppender fa = (FileAppender) a;
54 String filename = fa.getFile();
55 ret.add(new File(filename));
56 }
57 }
58 return ret;
59 }
60
61
62 public static void dumpTailOfLogs(
63 PrintWriter out, long tailKb) throws IOException {
64 Set<File> logs = LogMonitoring.getActiveLogFiles();
65 for (File f : logs) {
66 out.println("+++++++++++++++++++++++++++++++");
67 out.println(f.getAbsolutePath());
68 out.println("+++++++++++++++++++++++++++++++");
69 try {
70 dumpTailOfLog(f, out, tailKb);
71 } catch (IOException ioe) {
72 out.println("Unable to dump log at " + f);
73 ioe.printStackTrace(out);
74 }
75 out.println("\n\n");
76 }
77 }
78
79 private static void dumpTailOfLog(File f, PrintWriter out, long tailKb)
80 throws IOException {
81 FileInputStream fis = new FileInputStream(f);
82 BufferedReader r = null;
83 try {
84 FileChannel channel = fis.getChannel();
85 channel.position(Math.max(0, channel.size() - tailKb*1024));
86 r = new BufferedReader(new InputStreamReader(fis));
87 r.readLine();
88 String line;
89 while ((line = r.readLine()) != null) {
90 out.println(line);
91 }
92 } finally {
93 if (r != null) IOUtils.closeStream(r);
94 IOUtils.closeStream(fis);
95 }
96 }
97 }