factor db creation to its own package

db/db.go

@@ -0,0 +1,34 @@
+package db
+
+import (
+	"fmt"
+	"log"
+	"net/url"
+	"os"
+
+	"github.com/jinzhu/gorm"
+	"github.com/pkg/errors"
+)
+
+var (
+	dbMaxOpenConns = 1
+	dbOptions      = url.Values{
+		// with this, multiple connections share a single data and schema cache.
+		// see https://www.sqlite.org/sharedcache.html
+		"cache": []string{"shared"},
+		// with this, the db sleeps for a little while when locked. can prevent
+		// a SQLITE_BUSY. see https://www.sqlite.org/c3ref/busy_timeout.html
+		"_busy_timeout": []string{"30000"},
+	}
+)
+
+func New(path string) (*gorm.DB, error) {
+	pathAndArgs := fmt.Sprintf("%s?%s", path, dbOptions.Encode())
+	db, err := gorm.Open("sqlite3", pathAndArgs)
+	if err != nil {
+		return nil, errors.Wrap(err, "with gorm")
+	}
+	db.DB().SetMaxOpenConns(dbMaxOpenConns)
+	db.SetLogger(log.New(os.Stdout, "gorm ", 0))
+	return db, nil
+}