Add stackcollapse for java error stacks in logs

stackcollapse-java-exceptions.pl

@@ -0,0 +1,71 @@
+#!/usr/bin/perl -w
+#
+# stackcolllapse-java-exceptions.pl	collapse java exceptions (found in logs) into single lines.
+#
+# Parses Java error stacks found in a log file and outputs them as
+# single lines, with methods separated by semicolons, and then a space and an
+# occurrence count. Inspired by stackcollapse-jstack.pl except that it does
+# not act as a performance profiler.
+#
+# It can be useful if a Java process dumps a lot of different stacks in its logs
+# and you want to quickly identify the biggest culprits.
+#
+# USAGE: ./stackcollapse-java-exceptions.pl infile > outfile
+#
+# Copyright 2018 Paul de Verdiere. All rights reserved.
+
+use strict;
+use Getopt::Long;
+
+# tunables
+my $shorten_pkgs = 0;		# shorten package names
+my $no_pkgs = 0;		    # really shorten package names!!
+my $help = 0;
+
+sub usage {
+	die <<USAGE_END;
+USAGE: $0 [options] infile > outfile\n
+	--shorten-pkgs : shorten package names
+  --no-pkgs      : suppress package names (makes SVG much more readable)
+
+USAGE_END
+}
+
+GetOptions(
+	'shorten-pkgs!'   => \$shorten_pkgs,
+	'no-pkgs!'        => \$no_pkgs,
+	'help'            => \$help,
+) or usage();
+$help && usage();
+
+my %collapsed;
+
+sub remember_stack {
+	my ($stack, $count) = @_;
+	$collapsed{$stack} += $count;
+}
+
+my @stack;
+
+foreach (<>) {
+	chomp;
+
+  if (/^\s*at ([^\(]*)/) {
+		my $func = $1;
+		if ($shorten_pkgs || $no_pkgs) {
+			my ($pkgs, $clsFunc) = ( $func =~ m/(.*\.)([^.]+\.[^.]+)$/ );
+			$pkgs =~ s/(\w)\w*/$1/g;
+      $func = $no_pkgs ? $clsFunc: $pkgs . $clsFunc;
+		}
+		unshift @stack, $func;
+	} elsif (@stack ) {
+		remember_stack(join(";", @stack), 1) if @stack;
+		undef @stack;
+  }
+}
+
+remember_stack(join(";", @stack), 1) if @stack;
+
+foreach my $k (sort { $a cmp $b } keys %collapsed) {
+	print "$k $collapsed{$k}\n";
+}