fix(installer): Fix reporting of error code

pkg/fleet/daemon/daemon.go

@@ -494,7 +494,10 @@ func (d *daemonImpl) handleRemoteAPIRequest(request remoteAPIRequest) (err error
 		}
 		experimentPackage, ok := d.catalog.getPackage(request.Package, params.Version, runtime.GOARCH, runtime.GOOS)
 		if !ok {
-			return fmt.Errorf("could not get package %s, %s for %s, %s", request.Package, params.Version, runtime.GOARCH, runtime.GOOS)
+			return installerErrors.Wrap(
+				installerErrors.ErrPackageNotFound,
+				fmt.Errorf("could not get package %s, %s for %s, %s", request.Package, params.Version, runtime.GOARCH, runtime.GOOS),
+			)
 		}
 		log.Infof("Installer: Received remote request %s to start experiment for package %s version %s", request.ID, request.Package, request.Params)
 		if request.Package == "datadog-installer" {

pkg/fleet/installer/errors/errors.go

@@ -105,16 +105,16 @@ func (e InstallerError) ToJSON() string {
 }
 
 // FromJSON returns an InstallerError from a JSON string.
-func FromJSON(errStr string) InstallerError {
+func FromJSON(errStr string) *InstallerError {
 	var jsonError installerErrorJSON
 	err := json.Unmarshal([]byte(errStr), &jsonError)
 	if err != nil {
-		return InstallerError{
+		return &InstallerError{
 			err:  errors.New(errStr),
 			code: errUnknown,
 		}
 	}
-	return InstallerError{
+	return &InstallerError{
 		err:  errors.New(jsonError.Error),
 		code: InstallerErrorCode(jsonError.Code),
 	}

pkg/fleet/internal/exec/installer_exec.go

@@ -252,5 +252,5 @@ func (iCmd *installerCmd) Run() error {
 	}
 
 	installerError := installerErrors.FromJSON(strings.TrimSpace(errBuf.String()))
-	return fmt.Errorf("run failed: %v \n%s", installerError, err.Error())
+	return fmt.Errorf("run failed: %w \n%s", installerError, err.Error())
 }