Add ability to aggregate steve servers through remotedialer

pkg/aggregation/watch.go

@@ -0,0 +1,93 @@
+package aggregation
+
+import (
+	"bytes"
+	"context"
+	"net/http"
+
+	v1 "github.com/rancher/wrangler/pkg/generated/controllers/core/v1"
+	"github.com/sirupsen/logrus"
+	corev1 "k8s.io/api/core/v1"
+)
+
+func Watch(ctx context.Context, controller v1.SecretController, secretNamespace, secretName string, httpHandler http.Handler) {
+	if secretNamespace == "" || secretName == "" {
+		return
+	}
+	h := handler{
+		ctx:       ctx,
+		handler:   httpHandler,
+		namespace: secretNamespace,
+		name:      secretName,
+	}
+	controller.OnChange(ctx, "aggregation-controller", h.OnSecret)
+}
+
+type handler struct {
+	handler         http.Handler
+	namespace, name string
+
+	url    string
+	caCert []byte
+	token  string
+	ctx    context.Context
+	cancel func()
+}
+
+func (h *handler) OnSecret(key string, secret *corev1.Secret) (*corev1.Secret, error) {
+	if secret == nil {
+		return nil, nil
+	}
+
+	if secret.Namespace != h.namespace ||
+		secret.Name != h.name {
+		return secret, nil
+	}
+
+	url, caCert, token, restart, err := h.shouldRestart(secret)
+	if err != nil {
+		return secret, err
+	}
+	if !restart {
+		return secret, nil
+	}
+
+	if h.cancel != nil {
+		logrus.Info("Restarting steve aggregation client")
+		h.cancel()
+	} else {
+		logrus.Info("Starting steve aggregation client")
+	}
+
+	ctx, cancel := context.WithCancel(h.ctx)
+	go ListenAndServe(ctx, url, caCert, token, h.handler)
+
+	h.url = url
+	h.caCert = caCert
+	h.token = token
+	h.cancel = cancel
+
+	return secret, nil
+}
+
+func (h *handler) shouldRestart(secret *corev1.Secret) (string, []byte, string, bool, error) {
+	url := string(secret.Data["url"])
+	if url == "" {
+		return "", nil, "", false, nil
+	}
+
+	token := string(secret.Data["token"])
+	if token == "" {
+		return "", nil, "", false, nil
+	}
+
+	caCert := secret.Data["ca.crt"]
+
+	if h.url != url ||
+		h.token != token ||
+		bytes.Equal(h.caCert, caCert) {
+		return url, caCert, token, true, nil
+	}
+
+	return "", nil, "", false, nil
+}