Initial commit

struct/db.go

@@ -0,0 +1,96 @@
+package ckh
+
+import (
+	"database/sql"
+	"log"
+	"os"
+	"strings"
+	"time"
+	_ "github.com/go-sql-driver/mysql"
+)
+
+// db stores the connection to the database
+var db *sql.DB
+
+// DSNGenerator returns DSN filed with values from environment
+func DSNGenerator() string {
+	db_user := "checkhome"
+	db_password := "checkhome"
+	db_host := ""
+	db_db := "checkhome"
+
+	if v, exists := os.LookupEnv("MYSQL_HOST"); exists {
+		db_host = v
+	}
+	if v, exists := os.LookupEnv("MYSQL_PASSWORD"); exists {
+		db_password = v
+	} else if v, exists := os.LookupEnv("MYSQL_ROOT_PASSWORD"); exists {
+		db_user = "root"
+		db_password = v
+	}
+	if v, exists := os.LookupEnv("MYSQL_USER"); exists {
+		db_user = v
+	}
+	if v, exists := os.LookupEnv("MYSQL_DATABASE"); exists {
+		db_db = v
+	}
+
+	return db_user + ":" + db_password + "@" + db_host + "/" + db_db
+}
+
+// DBInit establishes the connection to the database
+func DBInit(dsn string) (err error) {
+	if db, err = sql.Open("mysql", dsn + "?parseTime=true&foreign_key_checks=1"); err != nil {
+		return
+	}
+
+	_, err = db.Exec(`SET SESSION sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';`)
+	for i := 0; err != nil && i < 15; i += 1 {
+		if _, err = db.Exec(`SET SESSION sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';`); err != nil && i <= 5 {
+			log.Println("An error occurs when trying to connect to DB, will retry in 2 seconds: ", err)
+			time.Sleep(2 * time.Second)
+		}
+	}
+
+	return
+}
+
+// DBCreate creates all necessary tables used by the package
+func DBCreate() (err error) {
+	ct := `
+CREATE TABLE IF NOT EXISTS rooms (id_room INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT, label TEXT NOT NULL);
+CREATE TABLE IF NOT EXISTS tags (id_tag INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT, label TEXT NOT NULL);
+CREATE TABLE IF NOT EXISTS items (id_item INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT, label TEXT NOT NULL, description TEXT NOT NULL, id_room INTEGER);
+CREATE TABLE IF NOT EXISTS item_tag (id_item INTEGER NOT NULL, id_tag INTEGER NOT NULL);
+CREATE TABLE IF NOT EXISTS users (id_user INTEGER NOT NULL, username VARCHAR(255), password BINARY(64));
+`
+	for _, ln := range strings.Split(ct, "\n") {
+		if len(ln) == 0 {
+			continue
+		}
+		if _, err = db.Exec(ln); err != nil {
+			return
+		}
+	}
+	return
+}
+
+func DBClose() error {
+	return db.Close()
+}
+
+func DBPrepare(query string) (*sql.Stmt, error) {
+	return db.Prepare(query)
+}
+
+func DBQuery(query string, args ...interface{}) (*sql.Rows, error) {
+	return db.Query(query, args...)
+}
+
+func DBExec(query string, args ...interface{}) (sql.Result, error) {
+	return db.Exec(query, args...)
+}
+
+func DBQueryRow(query string, args ...interface{}) *sql.Row {
+	return db.QueryRow(query, args...)
+}