refactor into cmd/pkg

1 files changed, 97 insertions, 0 deletions

diff --git a/pkg/config/main.go b/pkg/config/main.go
new file mode 100644
index 0000000..142738d
--- /dev/null
+++ b/pkg/config/main.go
@@ -0,0 +1,97 @@
+package config
+
+import (
+	"flag"
+	"log"
+	"os"
+	"reflect"
+)
+
+const DefaultAuthenticationModule = "anonymous"
+
+type Opts struct {
+	Notls  bool
+	CaCrt  string
+	CaKey  string
+	TlsCrt string
+	TlsKey string
+	Port   string
+	Auth   string
+}
+
+func (o *Opts) fallbackToEnv(field string, envVar string, defaultVal string) {
+	r := reflect.ValueOf(o)
+	f := reflect.Indirect(r).FieldByName(field)
+
+	if f.String() == "" {
+		val, exists := os.LookupEnv(envVar)
+		if exists && val != "" {
+			f.SetString(val)
+		} else {
+			f.SetString(defaultVal)
+		}
+	}
+}
+
+func doCaFilesSanityCheck(caCrt string, caKey string) {
+	if _, err := os.Stat(caCrt); os.IsNotExist(err) {
+		log.Fatal("cannot find caCrt file")
+	}
+	if _, err := os.Stat(caKey); os.IsNotExist(err) {
+		log.Fatal("cannot find caKey file")
+	}
+}
+
+func doTlsFilesSanityCheck(tlsCrt string, tlsKey string) {
+	if _, err := os.Stat(tlsCrt); os.IsNotExist(err) {
+		log.Fatal("cannot find tlsCrt file")
+	}
+	if _, err := os.Stat(tlsKey); os.IsNotExist(err) {
+		log.Fatal("cannot find tlsKey file")
+	}
+}
+
+func InitializeFlags(opts *Opts) {
+	flag.BoolVar(&opts.Notls, "notls", false, "disable TLS on the service")
+	flag.StringVar(&opts.CaCrt, "caCrt", "", "path to the CA public key")
+	flag.StringVar(&opts.CaKey, "caKey", "", "path to the CA private key")
+	flag.StringVar(&opts.TlsCrt, "tls_crt", "", "path to the cert file for TLS")
+	flag.StringVar(&opts.TlsKey, "tls_key", "", "path to the key file for TLS")
+	flag.StringVar(&opts.Port, "port", "", "port where the server will listen (default: 8000)")
+	flag.StringVar(&opts.Auth, "auth", "", "authentication module (anonymous, sip)")
+	flag.Parse()
+
+	opts.fallbackToEnv("CaCrt", "VPNWEB_CACRT", "")
+	opts.fallbackToEnv("CaKey", "VPNWEB_CAKEY", "")
+	opts.fallbackToEnv("TlsCrt", "VPNWEB_TLSCRT", "")
+	opts.fallbackToEnv("TlsKey", "VPNWEB_TLSKEY", "")
+	opts.fallbackToEnv("Port", "VPNWEB_PORT", "8000")
+	opts.fallbackToEnv("Auth", "VPNWEB_AUTH", DefaultAuthenticationModule)
+}
+
+func CheckConfigurationOptions(opts *Opts) {
+	if opts.CaCrt == "" {
+		log.Fatal("missing caCrt parameter")
+	}
+	if opts.CaKey == "" {
+		log.Fatal("missing caKey parameter")
+	}
+
+	if opts.Notls == false {
+		if opts.TlsCrt == "" {
+			log.Fatal("missing tls_crt parameter. maybe use -notls?")
+		}
+		if opts.TlsKey == "" {
+			log.Fatal("missing tls_key parameter. maybe use -notls?")
+		}
+	}
+
+	doCaFilesSanityCheck(opts.CaCrt, opts.CaKey)
+	if opts.Notls == false {
+		doTlsFilesSanityCheck(opts.TlsCrt, opts.TlsKey)
+	}
+
+	log.Println("Authentication module:", opts.Auth)
+
+	// TODO -- check authentication module is valud, bail out otherwise
+}