feat: app

db.go

@@ -0,0 +1,160 @@
+package main
+
+import (
+	"database/sql"
+	_ "embed"
+	"errors"
+	_ "github.com/glebarez/go-sqlite"
+	"log"
+	"os"
+)
+
+const dbFileName = "healthr.db"
+const driverName = "sqlite"
+
+type Database interface {
+	Initialize() error
+	GetAllStatus() ([]Service, error)
+	Get(serviceName string) *Service
+	Update(service Service) error
+}
+
+type SqliteDatabase struct {
+}
+
+//go:embed sql_queries/init-db.sql
+var initDbQuery string
+
+func (sqldb *SqliteDatabase) Initialize() error {
+	fileInfo, err := os.Stat(dbFileName)
+	if fileInfo != nil && fileInfo.IsDir() {
+		return errors.New(dbFileName + " is exists, but is a directory instead of a file")
+	}
+
+	if err == nil {
+		return nil
+	}
+
+	db, err := sql.Open(driverName, dbFileName)
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	defer db.Close()
+
+	db.Exec(initDbQuery)
+	log.Default().Println("Database initialized!")
+
+	return nil
+}
+
+//go:embed sql_queries/get-service.sql
+var getServiceQuery string
+
+func (sqldb *SqliteDatabase) Get(serviceName string) *Service {
+	db, err := sql.Open(driverName, dbFileName)
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	defer db.Close()
+
+	rows, err := db.Query(getServiceQuery, serviceName)
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	defer rows.Close()
+
+	hasItem := rows.Next()
+	if !hasItem {
+		return nil
+	}
+
+	var service Service
+	err = rows.Scan(&service.Name, &service.Healthy)
+	if err != nil {
+		log.Fatal(err.Error())
+		return nil
+	}
+
+	return &service
+}
+
+//go:embed sql_queries/get-all.sql
+var getAllQuery string
+
+func (sqldb *SqliteDatabase) GetAllStatus() ([]Service, error) {
+	db, err := sql.Open(driverName, dbFileName)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	rows, err := db.Query(getAllQuery)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer rows.Close()
+
+	services := make([]Service, 0)
+
+	for rows.Next() {
+		var service Service
+		if err := rows.Scan(&service.Name, &service.Healthy); err != nil {
+			log.Default().Print("Error while parsing row", err)
+		}
+
+		services = append(services, service)
+	}
+
+	return services, nil
+}
+
+func (sqldb *SqliteDatabase) Update(service Service) error {
+	sqldb.Get(service.Name)
+	existingService := sqldb.Get(service.Name)
+
+	if existingService == nil {
+		return sqldb.insert(service)
+	} else {
+		return sqldb.update(service)
+	}
+}
+
+//go:embed sql_queries/insert-service.sql
+var insertQuery string
+
+func (sqldb *SqliteDatabase) insert(service Service) error {
+	db, err := sql.Open(driverName, dbFileName)
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	defer db.Close()
+
+	_, err = db.Exec(insertQuery, service.Name, service.Healthy)
+
+	if err != nil {
+		println("ERROR", err.Error())
+		return err
+	}
+
+	return nil
+}
+
+//go:embed sql_queries/update-service.sql
+var updateQuery string
+
+func (sqldb *SqliteDatabase) update(service Service) error {
+	db, err := sql.Open(driverName, dbFileName)
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	defer db.Close()
+
+	_, err = db.Exec(updateQuery, service.Name, service.Healthy, service.Name)
+
+	if err != nil {
+		println("ERROR", err.Error())
+		return err
+	}
+
+	return nil
+}