Create key and certificate in golang same as openssl do for local host

Question

How can I code in Go the equivalent of the following openssl command?

openssl req -subj /C=/ST=/O=/L=/CN=localhost/OU=/ -x509 -nodes -days 3650  \
            -newkey rsa:4096 -keyout test.key -out test.crt

The goal is to generate a new certificate from its certificate request.

Answer 1

Found my solution by this way-

key, err := rsa.GenerateKey(rand.Reader, 4096)
    if err != nil {
        return "", "", err
    }
    keyBytes := x509.MarshalPKCS1PrivateKey(key)
    // PEM encoding of private key
    keyPEM := pem.EncodeToMemory(
        &pem.Block{
            Type:  "RSA PRIVATE KEY",
            Bytes: keyBytes,
        },
    )
    fmt.Println(string(keyPEM))
    
    notBefore := time.Now()
    notAfter := notBefore.Add(365*24*10*time.Hour)

    //Create certificate templet
    template := x509.Certificate{
        SerialNumber:          big.NewInt(0),
        Subject:               pkix.Name{CommonName: "localhost"},
        SignatureAlgorithm:    x509.SHA256WithRSA,
        NotBefore:             notBefore,
        NotAfter:              notAfter,
        BasicConstraintsValid: true,
        KeyUsage:              x509.KeyUsageDigitalSignature | x509.KeyUsageKeyAgreement | x509.KeyUsageKeyEncipherment | x509.KeyUsageDataEncipherment,
        ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
    }
    //Create certificate using templet
    derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &key.PublicKey, key)
    if err != nil {
        return "", "", err

    }
    //pem encoding of certificate
    certPem := string(pem.EncodeToMemory(
        &pem.Block{
            Type:  "CERTIFICATE",
            Bytes: derBytes,
        },
    ))
    fmt.Println(certPem))