Basic retention scanner w/ unit tests

Not wired into anything yet!

smtpd/retention.go

@@ -1,12 +1,37 @@
 package smtpd
 
 import (
-	//"github.com/jhillyerd/inbucket/config"
-	//"github.com/jhillyerd/inbucket/log"
-//	"io/ioutil"
+	"github.com/jhillyerd/inbucket/log"
+	"time"
 )
 
 // retentionScan does a single pass of all mailboxes looking for messages that can be purged
-func retentionScan(ds *DataStore) {
+func retentionScan(ds DataStore, maxAge time.Duration, sleep time.Duration) error {
+	log.Trace("Starting retention scan")
+	cutoff := time.Now().Add(-1 * maxAge)
+	mboxes, err := ds.AllMailboxes()
+	if err != nil {
+		return err
+	}
 
+	for _, mb := range mboxes {
+		messages, err := mb.GetMessages()
+		if err != nil {
+			return err
+		}
+		for _, msg := range messages {
+			if msg.Date().Before(cutoff) {
+				log.Trace("Purging expired message %v", msg.Id())
+				err = msg.Delete()
+				if err != nil {
+					// Log but don't abort
+					log.Error("Failed to purge message %v: %v", msg.Id(), err)
+				}
+			}
+		}
+		// Sleep after completing a mailbox
+		time.Sleep(sleep)
+	}
+
+	return nil
 }