Load identity certificate from disk in each connection.

ca/identity/client.go

@@ -60,7 +60,9 @@ func LoadClient() (*Client, error) {
 
 	// Prepare transport with information in defaults.json and identity.json
 	tr := http.DefaultTransport.(*http.Transport).Clone()
-	tr.TLSClientConfig = &tls.Config{}
+	tr.TLSClientConfig = &tls.Config{
+		GetClientCertificate: identity.GetClientCertificateFunc(),
+	}
 
 	// RootCAs
 	b, err = ioutil.ReadFile(defaults.Root)
@@ -72,13 +74,6 @@ func LoadClient() (*Client, error) {
 		tr.TLSClientConfig.RootCAs = pool
 	}
 
-	// Certificate
-	crt, err := tls.LoadX509KeyPair(identity.Certificate, identity.Key)
-	if err != nil {
-		return nil, fmt.Errorf("error loading certificate: %v", err)
-	}
-	tr.TLSClientConfig.Certificates = []tls.Certificate{crt}
-
 	return &Client{
 		CaURL: caURL,
 		Client: &http.Client{

ca/identity/client_test.go

@@ -185,11 +185,21 @@ func TestLoadClient(t *testing.T) {
 					t.Errorf("LoadClient() = %#v, want %#v", got, tt.want)
 				}
 			} else {
-				if !reflect.DeepEqual(got.CaURL, tt.want.CaURL) ||
-					!reflect.DeepEqual(got.Client.Transport.(*http.Transport).TLSClientConfig.RootCAs, tt.want.Client.Transport.(*http.Transport).TLSClientConfig.RootCAs) ||
-					!reflect.DeepEqual(got.Client.Transport.(*http.Transport).TLSClientConfig.Certificates, tt.want.Client.Transport.(*http.Transport).TLSClientConfig.Certificates) {
+				gotTransport := got.Client.Transport.(*http.Transport)
+				wantTransport := tt.want.Client.Transport.(*http.Transport)
+				if gotTransport.TLSClientConfig.GetClientCertificate == nil {
+					t.Error("LoadClient() transport does not define GetClientCertificate")
+				} else if !reflect.DeepEqual(got.CaURL, tt.want.CaURL) || !reflect.DeepEqual(gotTransport.TLSClientConfig.RootCAs, wantTransport.TLSClientConfig.RootCAs) {
 					t.Errorf("LoadClient() = %#v, want %#v", got, tt.want)
+				} else {
+					crt, err := gotTransport.TLSClientConfig.GetClientCertificate(nil)
+					if err != nil {
+						t.Errorf("LoadClient() GetClientCertificate error = %v", err)
+					} else if !reflect.DeepEqual(*crt, wantTransport.TLSClientConfig.Certificates[0]) {
+						t.Errorf("LoadClient() GetClientCertificate crt = %#v, want %#v", *crt, wantTransport.TLSClientConfig.Certificates[0])
+					}
 				}
+
 			}
 		})
 	}

ca/identity/identity.go

@@ -203,6 +203,18 @@ func (i *Identity) TLSCertificate() (tls.Certificate, error) {
 	}
 }
 
+// GetClientCertificateFunc returns a method that can be used as the
+// GetClientCertificate property in a tls.Config.
+func (i *Identity) GetClientCertificateFunc() func(*tls.CertificateRequestInfo) (*tls.Certificate, error) {
+	return func(*tls.CertificateRequestInfo) (*tls.Certificate, error) {
+		crt, err := tls.LoadX509KeyPair(i.Certificate, i.Key)
+		if err != nil {
+			return nil, errors.Wrap(err, "error loading identity certificate")
+		}
+		return &crt, nil
+	}
+}
+
 // Renewer is that interface that a renew client must implement.
 type Renewer interface {
 	GetRootCAs() *x509.CertPool