epn: improve detecting epn issues

make epn worker die on invalid requests and detect those errors as well.

epn.go

@@ -59,6 +59,8 @@ var (
 	ePNRestartPattern = []string{
 		"Attempt to free nonexistent shared string",
 		", Perl interpreter: ",
+		"**ePN: invalid request:",
+		"/mod_gearman_worker_epn.pl line ",
 	}
 )
 
@@ -318,6 +320,16 @@ func executeWithEmbeddedPerl(cmd *command, result *answer, received *receivedStr
 		return fmt.Errorf("json unpacking failed: %w: %s", err, err.Error())
 	}
 
+	for _, p := range ePNRestartPattern {
+		if strings.Contains(res.Stdout, p) {
+			logger.Errorf("found epn error, triggering epn server restart")
+			logger.Errorf("%s", res.Stdout)
+			ePNStarted = nil
+			received.Canceled = true
+			return fmt.Errorf("check result matched restart pattern: %s", p)
+		}
+	}
+
 	result.output = res.Stdout
 	result.returnCode = res.RC
 	result.compileDuration = res.CompileDuration

mod_gearman_worker_epn.pl

@@ -187,6 +187,7 @@ sub _handle_connection {
     eval {
         my $req     = <$client>;
         my $request = _parse_request($req);
+        die("**ePN: invalid request: ".($req // 'undef')) unless $request->{'bin'};
         $res        = _handle_request($request);
     };
     my $err = $@;
@@ -324,6 +325,7 @@ sub _test_run {
     eval {
         my $req     = join(" ", @{$args});
         my $request = _parse_request($req);
+        die("**ePN: invalid request: ".($req // 'undef')) unless $request->{'bin'};
         $res        = _handle_request($request, 1);
     };
     my $err = $@;