fix: Handle accept result and download result errors (#416)

* fix: Add accept result error handling

* fix: Add download result error handling

* fix: Check download path before downloading

If the path exists, we have already attempted to download the results.

* fix: Unblock error channel

The unbuffered error channel blocks on the receiver which does not
get set up in time. The buffered channel will hold the message until
the receiver is available.

pkg/jobcreator/controller.go

@@ -2,7 +2,10 @@ package jobcreator
 
 import (
 	"context"
+	"errors"
 	"fmt"
+	"io/fs"
+	"os"
 	"time"
 
 	"github.com/lilypad-tech/lilypad/pkg/data"
@@ -161,7 +164,7 @@ func (controller *JobCreatorController) subscribeToWeb3() error {
 }
 
 func (controller *JobCreatorController) Start(ctx context.Context, cm *system.CleanupManager) chan error {
-	errorChan := make(chan error)
+	errorChan := make(chan error, 1)
 	err := controller.subscribeToSolver()
 	if err != nil {
 		errorChan <- err
@@ -319,9 +322,23 @@ func (controller *JobCreatorController) checkResults() error {
 			// there is an error with the job
 			// accept anyway
 			// TODO: trigger mediation here
-			controller.acceptResult(dealContainer)
+			err := controller.acceptResult(dealContainer)
+			if err != nil {
+				controller.log.Error("failed to accept results", err)
+				return err
+			}
 		} else {
-			controller.downloadResult(dealContainer)
+			// We check for all completed deals, including deals whose results
+			// we have already downloaded. Check the download path and download
+			// if results do not exist.
+			downloadPath := solver.GetDownloadsFilePath(dealContainer.ID)
+			if _, err := os.Stat(downloadPath); errors.Is(err, fs.ErrNotExist) {
+				err := controller.downloadResult(dealContainer)
+				if err != nil {
+					controller.log.Error("failed to download results", err)
+					return err
+				}
+			}
 		}
 	}
 
@@ -337,7 +354,11 @@ func (controller *JobCreatorController) downloadResult(dealContainer data.DealCo
 	controller.log.Debug("Downloaded results for job", solver.GetDownloadsFilePath(dealContainer.ID))
 
 	// TODO: activate the mediation check here
-	controller.acceptResult(dealContainer)
+	err = controller.acceptResult(dealContainer)
+	if err != nil {
+		controller.log.Error("failed to accept results", err)
+		return err
+	}
 
 	// work out if we should check or accept the results
 	// if controller.options.Mediation.CheckResultsPercentage >= rand.Intn(100) {