Run exporter in goroutine

Use channel to pass data from exporter to importer

models/interfaces.go

@@ -38,13 +38,13 @@ type ListensExport interface {
 	// Returns a list of all listens newer then oldestTimestamp.
 	// The returned list of listens is supposed to be ordered by the
 	// Listen.ListenedAt timestamp, with the oldest entry first.
-	ExportListens(oldestTimestamp time.Time) ([]Listen, error)
+	ExportListens(oldestTimestamp time.Time, results chan ListensResult)
 }
 
 // Must be implemented by services supporting the import of listens.
 type ListensImport interface {
 	// Imports the given list of listens.
-	ImportListens(listens []Listen, oldestTimestamp time.Time) (ImportResult, error)
+	ImportListens(results chan ListensResult, oldestTimestamp time.Time) (ImportResult, error)
 }
 
 // Must be implemented by services supporting the export of loves.
@@ -52,13 +52,23 @@ type LovesExport interface {
 	// Returns a list of all loves newer then oldestTimestamp.
 	// The returned list of listens is supposed to be ordered by the
 	// Love.Created timestamp, with the oldest entry first.
-	ExportLoves(oldestTimestamp time.Time) ([]Love, error)
+	ExportLoves(oldestTimestamp time.Time, results chan LovesResult)
 }
 
 // Must be implemented by services supporting the import of loves.
 type LovesImport interface {
 	// Imports the given list of loves.
-	ImportLoves(loves []Love, oldestTimestamp time.Time) (ImportResult, error)
+	ImportLoves(results chan LovesResult, oldestTimestamp time.Time) (ImportResult, error)
+}
+
+type ListensResult struct {
+	Error   error
+	Listens ListensList
+}
+
+type LovesResult struct {
+	Error error
+	Loves LovesList
 }
 
 type ImportResult struct {