Return non-0 exit code from copilot upload failure

 - The current copilot behavior is to:

   * try to upload the specified file
   * if an error occurs, try to write an error file instead
     * if the error file write succeeds, return success -- otherwise error

   This behavior is not ideal, because it suppresses real issues like
   the inability to find the expected output file. While a case can be
   made that the sidecar succeeded in handling its responsibility,
   important information is lost in the process that is useful to other
   containers in the job.

   Generallyk, it's better to consider the inability to
   find the original file a failure of the job to produce the expected
   file in the expected location (useful especially for container tasks).
   That means that a failure to upload the file should also return a
   non-0 exit code.

 - The new behavior is therefore:

   * try to upload the specified file
   * if an error occurs, try to write an error file instead
     * if the error file write succeeds, return the original error
     * if the error file write fails, return a joined version of the
       errors

Signed-off-by: ddl-ebrown <[email protected]>

flytecopilot/cmd/sidecar.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"context"
+	stderrors "errors"
 	"fmt"
 	"time"
 
@@ -144,10 +145,13 @@ func (u *UploadOptions) Sidecar(ctx context.Context) error {
 
 	if err := u.uploader(ctx); err != nil {
 		logger.Errorf(ctx, "Uploading failed, err %s", err)
-		if err := u.UploadError(ctx, "OutputUploadFailed", err, storage.DataReference(u.remoteOutputsPrefix)); err != nil {
-			logger.Errorf(ctx, "Failed to write error document, err :%s", err)
-			return err
+		if uerr := u.UploadError(ctx, "OutputUploadFailed", err, storage.DataReference(u.remoteOutputsPrefix)); uerr != nil {
+			logger.Errorf(ctx, "Failed to write error document, err :%s", uerr)
+			return stderrors.Join(uerr, err)
 		}
+
+		// failure to upload should still return err exit code from process
+		return err
 	}
 	return nil
 }