Add support for self-signed CA certificates (#2268)

Co-authored-by: Bassem Dghaidi <568794+Link-@users.noreply.github.com>
Co-authored-by: Nikola Jokic <jokicnikola07@gmail.com>
Co-authored-by: Tingluo Huang <tingluohuang@github.com>

apis/actions.github.com/v1alpha1/tls_config_test.go

@@ -0,0 +1,105 @@
+package v1alpha1_test
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"net/http"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/actions/actions-runner-controller/apis/actions.github.com/v1alpha1"
+	"github.com/actions/actions-runner-controller/github/actions/testserver"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	v1 "k8s.io/api/core/v1"
+)
+
+func TestGitHubServerTLSConfig_ToCertPool(t *testing.T) {
+	t.Run("returns an error if CertificateFrom not specified", func(t *testing.T) {
+		c := &v1alpha1.GitHubServerTLSConfig{
+			CertificateFrom: nil,
+		}
+
+		pool, err := c.ToCertPool(nil)
+		assert.Nil(t, pool)
+
+		require.Error(t, err)
+		assert.Equal(t, err.Error(), "certificateFrom not specified")
+	})
+
+	t.Run("returns an error if CertificateFrom.ConfigMapKeyRef not specified", func(t *testing.T) {
+		c := &v1alpha1.GitHubServerTLSConfig{
+			CertificateFrom: &v1alpha1.TLSCertificateSource{},
+		}
+
+		pool, err := c.ToCertPool(nil)
+		assert.Nil(t, pool)
+
+		require.Error(t, err)
+		assert.Equal(t, err.Error(), "configMapKeyRef not specified")
+	})
+
+	t.Run("returns a valid cert pool with correct configuration", func(t *testing.T) {
+		c := &v1alpha1.GitHubServerTLSConfig{
+			CertificateFrom: &v1alpha1.TLSCertificateSource{
+				ConfigMapKeyRef: &v1.ConfigMapKeySelector{
+					LocalObjectReference: v1.LocalObjectReference{
+						Name: "name",
+					},
+					Key: "key",
+				},
+			},
+		}
+
+		certsFolder := filepath.Join(
+			"../../../",
+			"github",
+			"actions",
+			"testdata",
+		)
+
+		fetcher := func(name, key string) ([]byte, error) {
+			cert, err := os.ReadFile(filepath.Join(certsFolder, "rootCA.crt"))
+			require.NoError(t, err)
+
+			pool := x509.NewCertPool()
+			ok := pool.AppendCertsFromPEM(cert)
+			assert.True(t, ok)
+
+			return cert, nil
+		}
+
+		pool, err := c.ToCertPool(fetcher)
+		require.NoError(t, err)
+		require.NotNil(t, pool)
+
+		// can be used to communicate with a server
+		serverSuccessfullyCalled := false
+		server := testserver.NewUnstarted(t, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			serverSuccessfullyCalled = true
+			w.WriteHeader(http.StatusOK)
+		}))
+
+		cert, err := tls.LoadX509KeyPair(
+			filepath.Join(certsFolder, "server.crt"),
+			filepath.Join(certsFolder, "server.key"),
+		)
+		require.NoError(t, err)
+
+		server.TLS = &tls.Config{Certificates: []tls.Certificate{cert}}
+		server.StartTLS()
+
+		client := &http.Client{
+			Transport: &http.Transport{
+				TLSClientConfig: &tls.Config{
+					RootCAs: pool,
+				},
+			},
+		}
+
+		_, err = client.Get(server.URL)
+		assert.NoError(t, err)
+		assert.True(t, serverSuccessfullyCalled)
+	})
+}