stead from pg

kv.go

@@ -0,0 +1,46 @@
+package with
+
+import (
+	"context"
+	"database/sql"
+)
+
+type SQLKV struct {
+	db *sql.DB
+}
+
+func KV(ctx context.Context, db *sql.DB, foo func(SQLKV) error) error {
+	if _, err := db.ExecContext(ctx, `
+		CREATE TABLE IF NOT EXISTS with_kv(
+			k TEXT PRIMARY KEY
+			, v TEXT
+		)
+	`); err != nil {
+		return err
+	}
+
+	return foo(SQLKV{db: db})
+}
+
+func (kv SQLKV) Get(ctx context.Context, k string) ([]byte, error) {
+	row := kv.db.QueryRowContext(ctx, `
+		SELECT v FROM with_kv WHERE k=$1
+	`, k)
+
+	var v []byte
+	if err := row.Scan(&v); err != nil {
+		return nil, err
+	}
+
+	return v, row.Err()
+}
+
+func (kv SQLKV) Set(ctx context.Context, k string, v []byte) error {
+	_, err := kv.db.ExecContext(ctx, `
+		INSERT INTO with_kv
+		(k, v) VALUES ($1, $2)
+		ON CONFLICT DO UPDATE
+		SET v=$2 WHERE k=$1
+	`, k, v)
+	return err
+}