log stderr on failed CGIs

1 files changed, 9 insertions, 1 deletions

diff --git a/contrib/cgi/spartan.go b/contrib/cgi/spartan.go
index 6994466..272bd92 100644
--- a/contrib/cgi/spartan.go
+++ b/contrib/cgi/spartan.go
@@ -1,11 +1,13 @@
 package cgi
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"strings"
 
 	sr "tildegit.org/tjp/sliderule"
+	"tildegit.org/tjp/sliderule/logging"
 	"tildegit.org/tjp/sliderule/spartan"
 )
 
@@ -29,11 +31,17 @@ func SpartanCGIDirectory(pathRoot, fsRoot string) sr.Handler {
 			return nil
 		}
 
-		stdout, exitCode, err := RunCGI(ctx, request, filepath, pathinfo)
+		stderr := &bytes.Buffer{}
+		stdout, exitCode, err := RunCGI(ctx, request, filepath, pathinfo, stderr)
 		if err != nil {
 			return spartan.ServerError(err)
 		}
 		if exitCode != 0 {
+			ctx.Value("warnlog").(logging.Logger).Log(
+				"msg", "cgi exited with non-zero exit code",
+				"code", exitCode,
+				"stderr", stderr.String(),
+			)
 			return spartan.ServerError(fmt.Errorf("CGI process exited with status %d", exitCode))
 		}