Timeout on Avro file decodes because some people have ridiculously lo…

…ng messages.

azkaban-common/src/java/azkaban/common/web/HdfsAvroFileViewer.java

@@ -27,7 +27,9 @@
 public class HdfsAvroFileViewer implements HdfsFileViewer {
 
     private static Logger logger = Logger.getLogger(HdfsAvroFileViewer.class);
-
+    // Will spend 5 seconds trying to pull data and then stop.
+    private static long STOP_TIME = 5000l;
+
     @Override
     public boolean canReadFile(FileSystem fs, Path path) {
 
@@ -79,8 +81,9 @@ public void displayFile(FileSystem fs,
             g.useDefaultPrettyPrinter();
             Encoder encoder = new JsonEncoder(schema, g);
 
+            long endTime = System.currentTimeMillis() + STOP_TIME;
             int lineno = 1; // line number starts from 1
-            while(avroDatastream.hasNext() && lineno <= endLine) {
+            while(avroDatastream.hasNext() && lineno <= endLine && System.currentTimeMillis() <= endTime) {
                 Object datum = avroDatastream.next();
                 if(lineno >= startLine) {
                     String record = "\n\n Record " + lineno + ":\n";