sdk: add a logger interface

we are now ready to make the sdk a separate module

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

util/util.go

@@ -11,7 +11,6 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/pem"
-	"errors"
 	"fmt"
 	"html/template"
 	"io"
@@ -423,19 +422,6 @@ func GetTLSCiphersFromNames(cipherNames []string) []uint16 {
 	return ciphers
 }
 
-// EncodeTLSCertToPem returns the specified certificate PEM encoded.
-// This can be verified using openssl x509 -in cert.crt  -text -noout
-func EncodeTLSCertToPem(tlsCert *x509.Certificate) (string, error) {
-	if len(tlsCert.Raw) == 0 {
-		return "", errors.New("invalid x509 certificate, no der contents")
-	}
-	publicKeyBlock := pem.Block{
-		Type:  "CERTIFICATE",
-		Bytes: tlsCert.Raw,
-	}
-	return string(pem.EncodeToMemory(&publicKeyBlock)), nil
-}
-
 // CheckTCP4Port quits the app if bind on the given IPv4 port fails.
 // This is a ugly hack to avoid to bind on an already used port.
 // It is required on Windows only. Upstream does not consider this