parallel: implemented --resume incl. test.

src/parallel

@@ -386,6 +386,7 @@ sub options_hash {
 	 "X" => \$::opt_X,
 	 "v" => \@::opt_v,
 	 "joblog=s" => \$::opt_joblog,
+	 "resume" => \$::opt_resume,
 	 "silent" => \$::opt_silent,
 	 "keep-order|keeporder|k" => \$::opt_k,
 	 "group" => \$::opt_group,
@@ -536,6 +537,7 @@ sub parse_options {
     $Global::arg_file_sep = "::::";
     $Global::trim = 'n';
     $Global::max_jobs_running = 0;
+    $Global::job_already_run = '';
 
     @ARGV=read_options();
 
@@ -727,7 +729,41 @@ sub parse_options {
     if(not defined $::opt_P) {
         $::opt_P = "100%";
     }
+    open_joblog();
+}
+
+sub open_joblog {
+    my $append = 0;
+    if($::opt_resume and not $::opt_joblog) {
+        print STDERR ("$Global::progname: --resume requires --joblog\n");
+	::wait_and_exit(255);
+    }
     if($::opt_joblog) {
+	if($::opt_resume) {
+	    if(open(JOBLOG, $::opt_joblog)) {
+		# Read the joblog
+		$append = <JOBLOG>; # If there is a header: Open as append later
+		while(<JOBLOG>) {
+		    if(/^(\d+)/) {
+			# This is 30% faster than set_job_already_run($1);
+			vec($Global::job_already_run,$1,1) = 1;
+		    } else {
+			print STDERR ("$Global::progname: Format of '$::opt_joblog' is wrong\n");
+			::wait_and_exit(255);
+		    }
+		}
+		close JOBLOG;
+	    }
+	}
+	if($append) {
+	    # Append to joblog
+	    if(not open($Global::joblog,">>$::opt_joblog")) {
+		print STDERR ("$Global::progname: Cannot append to ",
+			      "--joblog $::opt_joblog\n");
+		::wait_and_exit(255);
+	    }
+	} else {
+	    # Overwrite the joblog
 	    if(not open($Global::joblog,">$::opt_joblog")) {
 		print STDERR ("$Global::progname: Cannot write to ",
 			      "--joblog $::opt_joblog\n");
@@ -740,6 +776,8 @@ sub parse_options {
 	    }
 	}
     }
+}
+
 
 sub read_options {
     # Read options from command line, profile and $PARALLEL
@@ -1079,12 +1117,15 @@ sub start_another_job {
 	    debug("Not starting: JobQueue empty\n");
 	    return 0;
         } else {
-            my $job = get_job_with_sshlogin($sshlogin);
+            my $job;
+            do {
+		$job = get_job_with_sshlogin($sshlogin);
 		if(not defined $job) {
 		    # No command available for that sshlogin
 		    debug("Not starting: no jobs available for ".$sshlogin->string()."\n");
 		    return 0;
 		}
+	    } while ($job->is_already_in_joblog());
 	    debug("Command to run on '".$job->sshlogin()."': '".$job->replaced()."'\n");
             if($job->start()) {
                 $Global::running{$job->pid()} = $job;
@@ -3496,6 +3537,16 @@ sub start {
     return $job;
 }
 
+sub is_already_in_joblog {
+    my $job = shift;
+    return vec($Global::job_already_run,$job->seq(),1);
+}
+
+sub set_job_in_joblog {
+    my $job = shift;
+    vec($Global::job_already_run,$job->seq(),1) = 1;
+}
+
 sub should_be_retried {
     # Should this job be retried?
     # Returns
@@ -3551,6 +3602,7 @@ sub print {
 		 $self->exitstatus(), $self->exitsignal(), $cmd
 		 ). "\n";
 	flush $Global::joblog;
+	$self->set_job_in_joblog();
     }
 
     if(($::opt_dryrun or $Global::verbose) and $Global::grouped) {

src/parallel.pod

@@ -525,6 +525,8 @@ To convert the times into ISO-8601 strict do:
 
 B<perl -a -F"\t" -ne 'chomp($F[2]=`date -d \@$F[2] +%FT%T`); print join("\t",@F)'>
 
+See also B<--resume>.
+
 
 =item B<--jobs> I<N>
 
@@ -923,6 +925,17 @@ it to the command.
 Only used with B<--pipe>.
 
 
+=item B<--resume>
+
+Resumes from the last unfinished job. By reading B<--joblog> GNU
+B<parallel> will figure out the last unfinished job and continue from
+there. As GNU B<parallel> only looks at the sequence numbers in
+B<--joblog> then the input, the command, and B<--joblog> all have to
+remain unchanged; otherwise GNU B<parallel> may run wrong commands.
+
+See also: B<--joblog>.
+
+
 =item B<--retries> I<n>
 
 If a job fails, retry it on another computer. Do this I<n> times. If

testsuite/tests-to-run/test65.sh

@@ -12,6 +12,18 @@ echo '### Test retired';
   stdout parallel -U; 
   stdout parallel -W; 
   stdout parallel -Y;
+echo '### Test --joblog followed by --resume --joblog'; 
+  rm -f /tmp/joblog; 
+  timeout -k 1 1 parallel -j2 --joblog /tmp/joblog sleep {} ::: 1.1 2.2 3.3 4.4 2>/dev/null; 
+  parallel -j2 --resume --joblog /tmp/joblog sleep {} ::: 1.1 2.2 3.3 4.4; 
+  cat /tmp/joblog | wc; 
+  rm -f /tmp/joblog;
+echo '### Test --resume --joblog followed by --resume --joblog'; 
+  rm -f /tmp/joblog2; 
+  timeout -k 1 1 parallel -j2 --resume --joblog /tmp/joblog2 sleep {} ::: 1.1 2.2 3.3 4.4 2>/dev/null; 
+  parallel -j2 --resume --joblog /tmp/joblog2 sleep {} ::: 1.1 2.2 3.3 4.4; 
+  cat /tmp/joblog2 | wc; 
+  rm -f /tmp/joblog2;
 EOF
 
 echo '### Test --shellquote'

testsuite/wanted-results/test30

@@ -19,8 +19,8 @@ Computers / CPU cores / Max jobs to run
 1:local / 2 / 1
 
 ### --timeout on remote machines
-1
+slept 1
-1
+slept 1
-2
+jobs failed: 2
 ### --pipe without command
 parallel: --pipe must have a command to pipe into (e.g. 'cat')

testsuite/wanted-results/test65

@@ -26,6 +26,10 @@ parallel: -U has been retired. Use --er.
 parallel: -W has been retired. Use --wd.
 parallel: -Y has been retired. Use --shebang.
 parallel: -H has been retired. Use --halt.
+### Test --joblog followed by --resume --joblog
+      5      49     205
+### Test --resume --joblog followed by --resume --joblog
+      5      49     205
 ### Test --shellquote
 awk\ -v\ FS=\"\\\",\\\"\"\ \'\{print\ \$1,\ \$3,\ \$4,\ \$5,\ \$9,\ \$14\}\'\ \|\ grep\ -v\ \"\#\"\ \|\ sed\ -e\ \'1d\'\ -e\ \'s/\\\"//g\'\ -e\ \'s/\\/\\/\\//\\t/g\'\ \|\ cut\ -f1-6,11\ \|\ sed\ -e\ \'s/\\/\\//\\t/g\'\ -e\ \'s/\ /\\t/g
 ### Test make .deb package