hydra-server: Support logs in S3

src/lib/Hydra/View/NixLog.pm

@@ -13,10 +13,17 @@ sub process {
 
     my $fh = new IO::Handle;
 
+    my $tail = int($c->stash->{tail} // "0");
+
     if ($logPath =~ /\.bz2$/) {
-        open $fh, "bzip2 -dc < '$logPath' |" or die;
+        my $doTail = $tail ? " tail -n '$tail' |" : "";
+        open $fh, "bzip2 -dc < '$logPath' | $doTail" or die;
     } else {
-        open $fh, "<$logPath" or die;
+        if ($tail) {
+            open $fh, "tail -n '$tail' '$logPath' |" or die;
+        } else {
+            open $fh, "<$logPath" or die;
+        }
     }
     binmode($fh);
 

src/lib/Hydra/View/TT.pm

@@ -13,17 +13,18 @@ __PACKAGE__->config(
 
 sub buildLogExists {
     my ($self, $c, $build) = @_;
+    return 1 if defined $c->config->{log_prefix};
     my @outPaths = map { $_->path } $build->buildoutputs->all;
     return defined findLog($c, $build->drvpath, @outPaths);
 }
 
 sub buildStepLogExists {
     my ($self, $c, $step) = @_;
+    return 1 if defined $c->config->{log_prefix};
     my @outPaths = map { $_->path } $step->buildstepoutputs->all;
     return defined findLog($c, $step->drvpath, @outPaths);
 }
 
-
 sub stripSSHUser {
     my ($self, $c, $name) = @_;
     if ($name =~ /^.*@(.*)$/) {