tsk-5: Fetch token (#9)

Closes #5

Reviewed-on: #9
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

internal/app/app.go

@@ -0,0 +1,51 @@
+package app
+
+import (
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/joho/godotenv"
+)
+
+const App_Name = "catapult"
+
+type App struct {
+	ApiUrl            string
+	AuthUrl           string
+	ServiceUsername   string
+	ServicePassphrase string
+}
+
+func Load() (*App, error) {
+	err := godotenv.Load()
+	if err != nil {
+		cwd, _ := os.Getwd()
+		envPath := path.Join(cwd, "../..", ".env")
+		if err = godotenv.Load(envPath); err != nil {
+			prevPath := path.Join(envPath, "../..", ".env")
+			if err = godotenv.Load(prevPath); err != nil {
+				return nil, fmt.Errorf("Error loading .env file: %w", err)
+			}
+		}
+	}
+
+	apiUrl := os.Getenv("API_URL")
+	authUrl := os.Getenv("AUTH_URL")
+	serviceUsername := os.Getenv("SERVICE_USERNAME")
+	servicePassphrase := os.Getenv("SERVICE_PASSPHRASE")
+
+	if len(apiUrl) == 0 {
+		return nil, fmt.Errorf("Api Url not provided")
+	} else if len(authUrl) == 0 {
+		return nil, fmt.Errorf("Auth url not provided")
+	} else if len(serviceUsername) == 0 {
+		return nil, fmt.Errorf("Service username not provided")
+	} else if len(servicePassphrase) == 0 {
+		return nil, fmt.Errorf("Service passphrase not provided")
+	} else {
+		return &App{
+			ApiUrl: apiUrl, AuthUrl: authUrl, ServiceUsername: serviceUsername, ServicePassphrase: servicePassphrase,
+		}, nil
+	}
+}