cmd/k8s-operator,k8s-operator/api-proxy: move k8s proxy code to library (#15857)

The defaultEnv and defaultBool functions are copied over temporarily
to minimise diff. This lays the ground work for having both the operator
and the new k8s-proxy binary implement the API proxy

Updates #13358

Change-Id: Ieacc79af64df2f13b27a18135517bb31c80a5a02
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>

cmd/k8s-operator/operator.go

@@ -45,6 +45,7 @@ import (
 	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
 	"tailscale.com/ipn/store/kubestore"
+	apiproxy "tailscale.com/k8s-operator/api-proxy"
 	tsapi "tailscale.com/k8s-operator/apis/v1alpha1"
 	"tailscale.com/kube/kubetypes"
 	"tailscale.com/tsnet"
@@ -102,8 +103,8 @@ func main() {
 	// The operator can run either as a plain operator or it can
 	// additionally act as api-server proxy
 	// https://tailscale.com/kb/1236/kubernetes-operator/?q=kubernetes#accessing-the-kubernetes-control-plane-using-an-api-server-proxy.
-	mode := parseAPIProxyMode()
-	if mode == apiserverProxyModeDisabled {
+	mode := apiproxy.ParseAPIProxyMode()
+	if mode == apiproxy.APIServerProxyModeDisabled {
 		hostinfo.SetApp(kubetypes.AppOperator)
 	} else {
 		hostinfo.SetApp(kubetypes.AppAPIServerProxy)
@@ -112,7 +113,7 @@ func main() {
 	s, tsc := initTSNet(zlog)
 	defer s.Close()
 	restConfig := config.GetConfigOrDie()
-	maybeLaunchAPIServerProxy(zlog, restConfig, s, mode)
+	apiproxy.MaybeLaunchAPIServerProxy(zlog, restConfig, s, mode)
 	rOpts := reconcilerOpts{
 		log:                           zlog,
 		tsServer:                      s,