gistfile1.txt

func (app *application) checkExpirationDate() {
	// Read the certificate file
	certPEM, err := os.ReadFile(app.ssl.crt)
	if err != nil {
		app.logger.Fatal("failed to read certificate file", zap.Error(err))
	}

	// Decode the PEM encoded certificate
	block, _ := pem.Decode(certPEM)
	if block == nil || block.Type != "CERTIFICATE" {
		app.logger.Fatal("failed to decode PEM block containing certificate")
	}

	// Parse the X.509 certificate
	cert, err := x509.ParseCertificate(block.Bytes)
	if err != nil {
		app.logger.Fatal("failed to parse certificate", zap.Error(err))
	}

	now := time.Now()
	duration := cert.NotAfter.Sub(now)
	remainingDays := int(duration.Hours() / 24)
	remainingHours := int(duration.Hours()) % 24

	// Print the expiration date
	app.logger.Info("Certificate expires on: ", zap.Int("days", remainingDays), zap.Int("hours", remainingHours))
}