pqd: Changed --resume to take a filename, added tests

bin/pt-query-digest

@@ -13820,9 +13820,8 @@ sub main {
                   push @read_files, $filename || "STDIN";
 
                   # Read the file offset for --resume.
-                  if ( $o->get('resume') && $filename ) {
-                     $resume_file = $filename . '.resume';
-                     if ( -f $resume_file ) {
+                  if ( ($resume_file = $o->get('resume')) && $filename ) {
+                     if ( -s $resume_file ) {
                         open my $resume_fh, '<', $resume_file
                            or die "Error opening $resume_file: $OS_ERROR";
                         chomp(my $resume_offset = <$resume_fh>);
@@ -16278,11 +16277,12 @@ See L<"OUTPUT"> for more information.
 
 =item --resume
 
-Resume parsing from the last file offset.  When specified, the tool
-writes the last file offset to C<FILE.resume> where C<FILE> is the original
-file name given on the command line.  When ran again with the exact same
-file name, the tool reads the last file offset from C<FILE.resume>,
-seeks to that position in the file, and resuming parsing events.
+type: string
+
+If specified, the tool writes the last file offset, if there is one,
+to the given filename. When ran again with the same value for this option,
+the tool reads the last file offset from the file, seeks to that position
+in the log, and resumes parsing events from that point onward.
 
 =item --review
 

t/pt-query-digest/resume.t

@@ -0,0 +1,163 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+
+use IO::File;
+use Fcntl      qw(:seek);
+use File::Temp qw(tempfile);
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-query-digest";
+
+my $dp = new DSNParser(opts=>$dsn_opts);
+my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $dbh = $sb->get_dbh_for('master');
+
+if ( !$dbh ) {
+   plan skip_all => 'Cannot connect to sandbox master';
+}
+
+my $samples = "$trunk/t/lib/samples/slowlogs";
+my $output;
+
+$sb->create_dbs($dbh, ['test']);
+
+my $resume_file = (tempfile())[1];
+
+my ($fh, $filename) = tempfile(UNLINK => 1);
+$fh->autoflush(1);
+
+sub resume_offset_ok {
+   my ($resume_file, $file, $msg) = @_;
+   chomp(my $offset = slurp_file($resume_file));
+   open my $tmp_fh, q{<}, $file or die $OS_ERROR;
+   seek $tmp_fh, 0, SEEK_END;
+   is(tell($tmp_fh), $offset, $msg);
+}
+
+sub run_pqd {
+   my @extra_args = @_;
+   my $run = output(sub { pt_query_digest::main(qw(--limit 10), @extra_args, $filename) }, stderr => 1);
+   $run =~ s/\d+ms user time.+//;
+   $run =~ s/Current date: .+//;
+   return $run;
+}
+
+print { $fh } slurp_file("$samples/slow006.txt");
+
+my @runs;
+push @runs, run_pqd() for 1, 2;
+
+is($runs[0], $runs[1], "Sanity check: Behaves the same between runs without --resume");
+
+my @resume_runs;
+push @resume_runs, run_pqd('--resume', $resume_file) for 1, 2;
+
+(my $without_resume_line = $resume_runs[0]) =~ s/\n\n. Saved resume file offset.+//;
+is(
+   $runs[0],
+   $without_resume_line,
+   "First time with --resume just like the first time without"
+);
+
+like(
+   $resume_runs[0],
+   qr/\QSaved resume file offset\E/,
+   "SAves offset with --resume"
+);
+
+like(
+   $resume_runs[1],
+   qr/\QNo events processed.\E/,
+   "..and there are no events on the second run"
+);
+
+resume_offset_ok($resume_file, $filename, "The resume file has the correct offset");
+
+print { $fh } slurp_file("$samples/slow002.txt");
+
+push @resume_runs, run_pqd('--resume', $resume_file) for 1, 2;
+
+unlike(
+   $resume_runs[2],
+   qr/\QNo events processed.\E/,
+   "New run detects new events"
+);
+
+like(
+   $resume_runs[3],
+   qr/\QNo events processed.\E/,
+   "And running again after that finds nothing new"
+);
+
+resume_offset_ok($resume_file, $filename, "The resume file has the updated offset");
+
+unlink($resume_file);
+
+close $fh;
+
+# #############################################################################
+# Now test the itneraction with --run-time-mode interval
+# #############################################################################
+
+($fh, $filename) = tempfile(UNLINK => 1);
+$fh->autoflush(1);
+
+print { $fh } slurp_file("$trunk/t/lib/samples/slowlogs/slow033.txt");
+
+my @run_args = (qw(--run-time-mode interval --run-time 1d --iterations 0),
+                qw(--report-format query_report));
+my @resume_args = (@run_args, '--resume', $resume_file);
+
+my @run_time;
+push @run_time, run_pqd(@resume_args) for 1,2;
+
+resume_offset_ok($resume_file, $filename, "The resume file has the correct offset when using --run-time-mode interval");
+
+print { $fh } slurp_file("$samples/slow002.txt");
+
+push @run_time, run_pqd(@resume_args) for 1,2;
+
+resume_offset_ok($resume_file, $filename, "...and it updates correctly");
+
+like(
+   $_,
+   qr/\QNo events processed.\E/,
+   "Runs 2 & 4 find no new data"
+) for @run_time[1, 3];
+
+# This shows up in the first report, but shouldn't show up in there
+# third run, after we add new events to the file.
+my $re = qr/\QSELECT * FROM foo\E/;
+
+unlike(
+   $run_time[2],
+   $re,
+   "Events from the first run are correctly ignored"
+);
+
+my $no_resume = run_pqd(@run_args);
+
+like(
+   $no_resume,
+   $re,
+   "...but do show up if run without resume"
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;
+exit;