15954: Ensure stdout is copied before returning from RunProgram.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@tomclegg.ca>

diff --git a/lib/boot/cmd.go b/lib/boot/cmd.go
index 62088a604d37bb875b5e906e2dd3e0032c927045..e2bb98542bb36decf4d23b446005ed2390cd738e 100644 (file)
--- a/lib/boot/cmd.go
+++ b/lib/boot/cmd.go
@@ -485,12 +485,21 @@ func (boot *Booter) RunProgram(ctx context.Context, dir string, output io.Writer
                return err
        }
        logwriter := &service.LogPrefixer{Writer: boot.Stderr, Prefix: []byte("[" + logprefix + "] ")}
-       go io.Copy(logwriter, stderr)
-       if output == nil {
-               go io.Copy(logwriter, stdout)
-       } else {
-               go io.Copy(output, stdout)
-       }
+       var copiers sync.WaitGroup
+       copiers.Add(1)
+       go func() {
+               io.Copy(logwriter, stderr)
+               copiers.Done()
+       }()
+       copiers.Add(1)
+       go func() {
+               if output == nil {
+                       io.Copy(logwriter, stdout)
+               } else {
+                       io.Copy(output, stdout)
+               }
+               copiers.Done()
+       }()
 
        if strings.HasPrefix(dir, "/") {
                cmd.Dir = dir
@@ -527,6 +536,7 @@ func (boot *Booter) RunProgram(ctx context.Context, dir string, output io.Writer
        if err != nil {
                return err
        }
+       copiers.Wait()
        err = cmd.Wait()
        if ctx.Err() != nil {
                // Return "context canceled", instead of the "killed"