[ws-daemon] Collect logs from runc command

components/common-go/log/log.go

@@ -6,6 +6,7 @@ package log
 
 import (
 	"fmt"
+	"io"
 	"os"
 
 	"github.com/sirupsen/logrus"
@@ -129,3 +130,29 @@ func (f *gcpFormatter) Format(entry *log.Entry) ([]byte, error) {
 
 	return f.JSONFormatter.Format(entry)
 }
+
+// Writer produces a writer that wraps everything that's written to it in a log message.
+// Callers are expected to close the returned writer.
+//
+// Beware: due to logEntry not being synchronised, writes to the returned writer must not
+//         concurrent.
+func Writer(logEntry *logrus.Entry) io.WriteCloser {
+	rd, rw := io.Pipe()
+	go func() {
+		b := make([]byte, 4096)
+		for {
+			n, err := rd.Read(b)
+			if err == io.EOF {
+				break
+			}
+			if err != nil {
+				log.WithError(err).Error("cannot read from content initializer output")
+				return
+			}
+
+			logEntry.Debug(string(b[:n]))
+		}
+	}()
+
+	return rw
+}

components/ws-daemon/pkg/content/initializer.go

@@ -229,10 +229,12 @@ func RunInitializer(ctx context.Context, destination string, initializer *csapi.
 		withDebug = "--debug"
 	}
 
+	rw := log.Writer(log.WithFields(opts.OWI))
+	defer rw.Close()
 	cmd = exec.Command("runc", "--root", "state", withDebug, "--log-format", "json", "run", "gogogo")
 	cmd.Dir = tmpdir
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
+	cmd.Stdout = rw
+	cmd.Stderr = rw
 	cmd.Stdin = os.Stdin
 	err = cmd.Run()
 	if err != nil {

components/ws-daemon/pkg/iws/iws.go

@@ -665,8 +665,11 @@ func nsinsider(instanceID string, targetPid int, mod func(*exec.Cmd), opts ...ns
 		cmd.ExtraFiles = append(cmd.ExtraFiles, f)
 	}
 
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
+	rw := log.Writer(log.WithFields(log.OWI("", "", instanceID)))
+	defer rw.Close()
+
+	cmd.Stdout = rw
+	cmd.Stderr = rw
 	err = cmd.Run()
 	if err != nil {
 		return fmt.Errorf("cannot run nsinsider: %w", err)