[TASK] add database

database/main.go

@@ -0,0 +1,79 @@
+// Package that provides the functionality to open, close and use a database
+package database
+
+import (
+	"github.com/jinzhu/gorm"
+	_ "github.com/jinzhu/gorm/dialects/postgres"
+	_ "github.com/jinzhu/gorm/dialects/sqlite"
+	_ "github.com/jinzhu/gorm/dialects/mysql"
+
+	"github.com/genofire/golang-lib/lib/log"
+)
+
+// Database connection for writing purposes
+var Write *gorm.DB
+
+// Database connection for reading purposes
+var Read *gorm.DB
+
+// Configuration files
+var (
+	config  *Config
+	runtime []interface{}
+)
+
+// Configuration of the database connection
+type Config struct {
+	// type of the database, currently supports sqlite and postgres
+	Type string
+	// connection configuration
+	Connection string
+	// create another connection for reading only
+	ReadConnection string
+	// enable logging of the generated sql string
+	Logging bool
+}
+
+// Function to open a database and set the given configuration
+func Open(c Config) (err error) {
+	writeLog := log.Log.WithField("db", "write")
+	config = &c
+	Write, err = gorm.Open(config.Type, config.Connection)
+	if err != nil {
+		return
+	}
+	Write.SingularTable(true)
+	Write.LogMode(c.Logging)
+	Write.SetLogger(writeLog)
+	Write.Callback().Create().Remove("gorm:update_time_stamp")
+	Write.Callback().Update().Remove("gorm:update_time_stamp")
+	if len(config.ReadConnection) > 0 {
+		readLog := log.Log.WithField("db", "read")
+		Read, err = gorm.Open(config.Type, config.ReadConnection)
+		if err != nil {
+			return
+		}
+		Read.SingularTable(true)
+		Read.LogMode(c.Logging)
+		Read.SetLogger(readLog)
+		Read.Callback().Create().Remove("gorm:update_time_stamp")
+		Read.Callback().Update().Remove("gorm:update_time_stamp")
+	} else {
+		Read = Write
+	}
+	Write.AutoMigrate(runtime...)
+	return
+}
+
+// Function to safely close the database
+func Close() {
+	Write.Close()
+	if len(config.ReadConnection) > 0 {
+		Read.Close()
+	}
+}
+
+// Function to add a model to the runtime
+func AddModel(m interface{}) {
+	runtime = append(runtime, m)
+}

database/main_test.go

@@ -0,0 +1,84 @@
+// Package that provides the functionality to open, close and use a database
+package database
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type TestModel struct {
+	ID    int64
+	Value string `gorm:"type:varchar(255);column:value" json:"value"`
+}
+
+// Function to test the error handling for the database opening
+func TestOpenNoDB(t *testing.T) {
+	assert := assert.New(t)
+
+	c := Config{}
+
+	err := Open(c)
+	assert.Error(err, "error")
+}
+
+// Function to test the opening of one database
+func TestOpenOneDB(t *testing.T) {
+	assert := assert.New(t)
+	AddModel(&TestModel{})
+
+	c := Config{
+		Type:       "sqlite3",
+		Logging:    true,
+		Connection: "file:database?mode=memory",
+	}
+	var count int64
+
+	err := Open(c)
+	assert.NoError(err, "no error")
+
+	Write.Create(&TestModel{Value: "first"})
+	Write.Create(&TestModel{Value: "secound"})
+
+	var list []*TestModel
+	Read.Find(&list).Count(&count)
+	assert.Equal(int64(2), count, "not enought entries")
+	Close()
+}
+
+// Function to test the opening of a second database
+func TestOpenTwoDB(t *testing.T) {
+	assert := assert.New(t)
+	AddModel(&TestModel{})
+	c := Config{
+		Type:           "sqlite3",
+		Logging:        true,
+		Connection:     "file:database?mode=memory",
+		ReadConnection: "file/",
+	}
+
+	err := Open(c)
+	assert.Error(err, "no error found")
+
+	c = Config{
+		Type:           "sqlite3",
+		Logging:        true,
+		Connection:     "file:database?mode=memory",
+		ReadConnection: "file:database2?mode=memory",
+	}
+	var count int64
+
+	err = Open(c)
+	assert.NoError(err, "no error")
+
+	Write.Create(&TestModel{Value: "first"})
+	Write.Create(&TestModel{Value: "secound"})
+
+	var list []*TestModel
+	Write.Find(&list).Count(&count)
+	assert.Equal(int64(2), count, "not enought entries")
+
+	result := Read.Find(&list)
+	assert.Error(result.Error, "error, because it is the wrong database")
+	Close()
+}