Adding the factory method to derive postgres implementation for db

app/server/src/db/constants.go

@@ -0,0 +1,10 @@
+package db
+
+// StorageType is the enum which defines the list of supported databases
+type StorageType int
+
+const (
+	PostgresDb StorageType = iota
+	MysqlDb
+	MongoDb
+)

app/server/src/db/db.go

@@ -7,10 +7,10 @@ type QueryInterface interface {
 
 // ConnectionInterface defines the interface that all db implementations must implement.
 type ConnectionInterface interface {
-	InitDb()
+	InitDb() error
 }
 
-type GoFitDb struct {
+type jdbcDb struct {
 	Dbhost             string
 	Dbport             string
 	Dbuser             string
@@ -18,3 +18,16 @@ type GoFitDb struct {
 	Dbname             string
 	MaxOpenConnections int
 }
+
+type postgresDb jdbcDb
+
+// NewDb returns an instance of the type of database that must be instantiated. For each new database type
+// it must implement the ConnectionInterface and the QueryInterface
+func NewDb(storageType StorageType) ConnectionInterface {
+	switch storageType {
+	case PostgresDb:
+		return &postgresDb{}
+	default:
+		return nil
+	}
+}

app/server/src/db/postgres.go

@@ -19,9 +19,7 @@ const (
 )
 
 // InitDb initializes the database
-func (d *GoFitDb) InitDb() {
-
-	var err error
+func (d *postgresDb) InitDb() (err error) {
 
 	// Initialize the database
 	d.dbConfig()
@@ -34,20 +32,21 @@ func (d *GoFitDb) InitDb() {
 	db, err = sql.Open("postgres", psqlInfo)
 
 	if err != nil {
-		panic(err)
+		return err
 	}
 	// Setup connection pool
 	db.SetMaxOpenConns(d.MaxOpenConnections)
 
 	err = db.Ping()
 	if err != nil {
-		panic(err)
+		return err
 	}
 	fmt.Println("Successfully connected!")
 	listTables()
+	return nil
 }
 
-func (d *GoFitDb) dbConfig() {
+func (d *postgresDb) dbConfig() {
 	var ok bool
 	d.Dbhost, ok = os.LookupEnv(dbhost)
 	if !ok {

app/server/src/server.go

@@ -10,8 +10,8 @@ import (
 )
 
 func main() {
-	goFitDb := db.GoFitDb{}
-	goFitDb.InitDb()
+	db := db.NewDb(db.PostgresDb)
+	db.InitDb()
 
 	router := httprouter.New()