Restore downloads directory before downloading (#2222) (#2229)

(cherry picked from commit fdd1465)

Co-authored-by: Michal Pristas <michal.pristas@gmail.com>

Author: mergify[bot]

internal/pkg/agent/application/upgrade/cleanup.go

@@ -22,6 +22,11 @@ func cleanNonMatchingVersionsFromDownloads(log *logger.Logger, version string) e
 	log.Debugw("Cleaning up non-matching downloaded versions", "version", version, "downloads.path", downloadsPath)
 
 	files, err := os.ReadDir(downloadsPath)
+	if os.IsNotExist(err) {
+		// nothing to clean up
+		return nil
+	}
+
 	if err != nil {
 		return fmt.Errorf("unable to read directory %q: %w", paths.Downloads(), err)
 	}

internal/pkg/agent/application/upgrade/step_download.go

@@ -6,10 +6,13 @@ package upgrade
 
 import (
 	"context"
+	"fmt"
+	"os"
 	"strings"
 
 	"go.elastic.co/apm"
 
+	"github.com/elastic/elastic-agent/internal/pkg/agent/application/paths"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact/download"
 	"github.com/elastic/elastic-agent/internal/pkg/agent/application/upgrade/artifact/download/composed"
@@ -54,6 +57,10 @@ func (u *Upgrader) downloadArtifact(ctx context.Context, version, sourceURI stri
 		return "", errors.New(err, "initiating fetcher")
 	}
 
+	if err := os.MkdirAll(paths.Downloads(), 0750); err != nil {
+		return "", errors.New(err, fmt.Sprintf("failed to create download directory at %s", paths.Downloads()))
+	}
+
 	path, err := fetcher.Download(ctx, agentArtifact, version)
 	if err != nil {
 		return "", errors.New(err, "failed upgrade of agent binary")