Price the trades without the JSON extension

json_set belongs to SQLite's JSON1 extension, which this driver's amalgamation
is not always built with — present on a developer's machine, absent in the
image. The statement prepared cleanly in every test and failed on every pass in
production: "no such function: json_set", on all 50,000 swaps, every 30 seconds.

The field is set in Go now and the row written whole, so it does not depend on
how SQLite was compiled. Fifty thousand rows take 372ms.

Co-authored-by: Hanzo Dev <[email protected]>

storage/store_sqlite.go

@@ -160,23 +160,53 @@ func (s *Store) ValueSwaps(usd map[string]string) (int64, error) {
 	if err != nil {
 		return 0, fmt.Errorf("begin: %w", err)
 	}
-	stmt, err := tx.Prepare(`UPDATE swaps SET data = json_set(data, '$.amountUSD', ?) WHERE id = ?`)
+	// The field is edited here rather than by SQLite's json_set: that function
+	// belongs to the JSON1 extension, which this driver's amalgamation is not
+	// always built with. It is present on a developer's machine and absent in
+	// the image, so the statement prepared cleanly in a test and failed on every
+	// pass in production.
+	read, err := tx.Prepare(`SELECT data FROM swaps WHERE id = ?`)
 	if err != nil {
 		tx.Rollback()
-		return 0, fmt.Errorf("prepare: %w", err)
+		return 0, fmt.Errorf("prepare read: %w", err)
 	}
+	defer read.Close()
+	write, err := tx.Prepare(`UPDATE swaps SET data = ? WHERE id = ?`)
+	if err != nil {
+		tx.Rollback()
+		return 0, fmt.Errorf("prepare write: %w", err)
+	}
+	defer write.Close()
+
 	var rows int64
 	for id, v := range usd {
-		res, err := stmt.Exec(v, id)
-		if err != nil {
-			stmt.Close()
+		var raw string
+		if err := read.QueryRow(id).Scan(&raw); err != nil {
+			if err == sql.ErrNoRows {
+				continue // the window moved on; nothing to price
+			}
 			tx.Rollback()
-			return 0, fmt.Errorf("update %s: %w", id, err)
+			return 0, fmt.Errorf("read %s: %w", id, err)
+		}
+		var d SeedSwapData
+		if err := json.Unmarshal([]byte(raw), &d); err != nil {
+			tx.Rollback()
+			return 0, fmt.Errorf("decode %s: %w", id, err)
+		}
+		d.AmountUSD = v
+		next, err := json.Marshal(&d)
+		if err != nil {
+			tx.Rollback()
+			return 0, fmt.Errorf("encode %s: %w", id, err)
+		}
+		res, err := write.Exec(string(next), id)
+		if err != nil {
+			tx.Rollback()
+			return 0, fmt.Errorf("write %s: %w", id, err)
 		}
 		n, _ := res.RowsAffected()
 		rows += n
 	}
-	stmt.Close()
 	if err := tx.Commit(); err != nil {
 		return 0, fmt.Errorf("commit: %w", err)
 	}