initial work for smarter database cleanup

src/storage/feed.go

@@ -194,3 +194,15 @@ func (s *Storage) GetFeedErrors() map[int64]string {
 	}
 	return errors
 }
+
+func (s *Storage) SetFeedSize(feedId int64, size int) {
+	_, err := s.db.Exec(`
+		insert into feed_sizes (feed_id, size)
+		values (?, ?)
+		on conflict (feed_id) do update set size = excluded.size`,
+		feedId, size,
+	)
+	if err != nil {
+		log.Print(err)
+	}
+}

src/storage/item.go

@@ -292,6 +292,13 @@ func (s *Storage) SyncSearch() {
 	}
 }
 
+
+// TODO: better naming
+var (
+	itemsKeepSize = 100
+	itemsKeepDays = 90
+)
+
 func (s *Storage) DeleteOldItems() {
 	rows, err := s.db.Query(fmt.Sprintf(`
 		select feed_id, count(*) as num_items
@@ -318,7 +325,7 @@ func (s *Storage) DeleteOldItems() {
 			delete from items where feed_id = ? and status != ? and date_arrived < ?`,
 			feedId,
 			STARRED,
-			time.Now().Add(-time.Hour*24*90), // 90 days
+			time.Now().Add(-time.Hour*time.Duration(24*itemsKeepDays)),
 		)
 		if err != nil {
 			log.Print(err)

src/storage/item_test.go

@@ -3,6 +3,7 @@ package storage
 import (
 	"log"
 	"reflect"
+	"strconv"
 	"testing"
 	"time"
 )
@@ -271,3 +272,57 @@ func TestMarkItemsRead(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestDeleteOldItems(t *testing.T) {
+	extraItems := 10
+
+	now := time.Now()
+	db := testDB()
+	feed := db.CreateFeed("feed", "", "", "http://test.com/feed11.xml", nil)
+
+	items := make([]Item, 0)
+	for i := 0; i < itemsKeepSize+extraItems; i++ {
+		istr := strconv.Itoa(i)
+		items = append(items, Item{
+			GUID:   istr,
+			FeedId: feed.Id,
+			Title:  istr,
+			Date:   now.Add(time.Hour * time.Duration(i)),
+		})
+	}
+	db.CreateItems(items)
+	
+	db.SetFeedSize(feed.Id, len(items))
+	var feedSize int
+	err := db.db.QueryRow(
+		`select size from feed_sizes where feed_id = ?`, feed.Id,
+	).Scan(&feedSize)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if feedSize != itemsKeepSize+extraItems {
+		t.Fatalf(
+			"expected feed size to get updated\nwant: %d\nhave: %d", 
+			itemsKeepSize+extraItems,
+			feedSize,
+		)
+	}
+
+	_, err = db.db.Exec(
+		`update items set date_arrived = ?`,
+		now.Add(-time.Hour*time.Duration(itemsKeepDays*24)),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	db.DeleteOldItems()
+	feedItems := db.ListItems(ItemFilter{FeedID: &feed.Id}, 1000, false)
+	if len(feedItems) != itemsKeepSize {
+		t.Fatalf(
+			"invalid number of old items kept\nwant: %d\nhave: %d",
+			itemsKeepSize,
+			len(feedItems),
+		)
+	}
+}

src/storage/migration.go

@@ -13,6 +13,7 @@ var migrations = []func(*sql.Tx) error{
 	m04_item_podcasturl,
 	m05_move_description_to_content,
 	m06_fill_missing_dates,
+	m07_add_feed_size,
 }
 
 var maxVersion = int64(len(migrations))
@@ -259,3 +260,14 @@ func m06_fill_missing_dates(tx *sql.Tx) error {
 	_, err := tx.Exec(sql)
 	return err
 }
+
+func m07_add_feed_size(tx *sql.Tx) error {
+	sql := `
+		create table if not exists feed_sizes (
+		 feed_id        references feeds(id) unique,
+		 size           integer not null default 0
+		);
+	`
+	_, err := tx.Exec(sql)
+	return err
+}

src/storage/storage_test.go

@@ -11,6 +11,7 @@ func testDB() *Storage {
 	log.SetOutput(io.Discard)
 	db, _ := New(":memory:")
 	log.SetOutput(os.Stderr)
+	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
 	return db
 }