Add go files from previous project

db.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+	"time"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type DB struct {
+	Ready     bool
+	path      string
+	readConn  *sql.DB
+	writeConn *sql.DB
+}
+
+func (db *DB) Open() error {
+	if db.path == "" {
+		return fmt.Errorf("database path not set")
+	}
+
+	file, err := os.Open(db.path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			log.Printf("Database file does not exist at %s, creating", db.path)
+			file, err := os.Create(db.path)
+			if err != nil {
+				return fmt.Errorf("failed to create database file: %v", err)
+			}
+			log.Printf("Database created at %s", db.path)
+			file.Close()
+		} else {
+			return fmt.Errorf("failed to open database file: %v", err)
+		}
+	}
+	file.Close()
+
+	writeConn, err := sql.Open("sqlite3", db.path+"?_journal=WAL&_synchronous=NORMAL")
+	if err != nil {
+		Error.Printf("%++v", err)
+		return err
+	}
+	writeConn.SetMaxOpenConns(1)
+	writeConn.SetConnMaxIdleTime(30 * time.Second)
+	writeConn.SetConnMaxLifetime(30 * time.Second)
+	db.writeConn = writeConn
+
+	readConn, err := sql.Open("sqlite3", db.path+"?mode=ro&_journal=WAL&_synchronous=NORMAL&_mode=ro")
+	if err != nil {
+		Error.Printf("%++v", err)
+		return err
+	}
+	readConn.SetMaxOpenConns(4)
+	readConn.SetConnMaxIdleTime(30 * time.Second)
+	readConn.SetConnMaxLifetime(30 * time.Second)
+	db.readConn = readConn
+
+	db.Ready = true
+	return nil
+}
+
+func (db *DB) Init(ddl string) error {
+	if !db.Ready {
+		return fmt.Errorf("database not ready")
+	}
+
+	var rows map[string]struct{} = make(map[string]struct{})
+	// TODO: Maybe make this better one day...
+	var expected = map[string]struct{}{
+		"Bill":     {},
+		"Payment":   {},
+	}
+
+	res, err := db.readConn.Query("SELECT name FROM sqlite_master WHERE type='table';")
+	if err != nil {
+		Error.Printf("%++v", err)
+		return err
+	}
+	defer res.Close()
+	for res.Next() {
+		var name string
+		err := res.Scan(&name)
+		if err != nil {
+			Error.Printf("%++v", err)
+			return err
+		}
+		rows[name] = struct{}{}
+	}
+
+	var needsInit bool
+	for table := range expected {
+		if _, ok := rows[table]; !ok {
+			log.Printf("Table %s not found, initializing", table)
+			needsInit = true
+			break
+		}
+	}
+
+	if !needsInit {
+		log.Printf("Database already initialized")
+		return nil
+	}
+
+	_, err = db.writeConn.Exec(ddl)
+	if err != nil {
+		Error.Printf("%++v", err)
+		log.Printf("%#v", "Rolling back")
+		_, err2 := db.writeConn.Exec("ROLLBACK;")
+		if err2 != nil {
+			Error.Printf("Error rolling back! %++v", err)
+		}
+		return err
+	}
+
+	log.Printf("Database init OK")
+	return nil
+}
+
+func (db *DB) Close() error {
+	err := db.writeConn.Close()
+	if err != nil {
+		return err
+	}
+
+	err = db.readConn.Close()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}