cmd/k8s-operator: use the client's authkey method to create auth keys.

Also introduces an intermediary interface for the tailscale client, in
preparation for operator tests that fake out the Tailscale API interaction.

Updates #502.

Signed-off-by: David Anderson <danderson@tailscale.com>

cmd/k8s-operator/main.go

@@ -7,14 +7,10 @@
 package main
 
 import (
-	"bytes"
 	"context"
 	_ "embed"
-	"encoding/json"
 	"fmt"
-	"io"
 	"log"
-	"net/http"
 	"os"
 	"strings"
 	"time"
@@ -182,7 +178,13 @@ const (
 type ServiceReconciler struct {
 	client.Client
 	defaultTags []string
-	tsClient    *tailscale.Client
+	tsClient    tsClient
+}
+
+type tsClient interface {
+	DeleteDevice(ctx context.Context, id string) error
+	Tailnet() string
+	CreateKey(ctx context.Context, caps tailscale.KeyCapabilities) (string, *tailscale.Key, error)
 }
 
 func childResourceLabels(parent *corev1.Service) map[string]string {
@@ -414,7 +416,7 @@ func (a *ServiceReconciler) createOrGetSecret(ctx context.Context, svc, hsvc *co
 	}
 
 	secret.StringData = map[string]string{
-		"authkey": authKey.Key,
+		"authkey": authKey,
 	}
 	if err := a.Create(ctx, secret); err != nil {
 		return "", err
@@ -463,36 +465,21 @@ type capability struct {
 	} `json:"devices"`
 }
 
-func (a *ServiceReconciler) newAuthKey(ctx context.Context, tags []string) (*authKey, error) {
-	var nkr newKeyRequest
-	nkr.Capabilities.Devices.Create.Reusable = false
-	nkr.Capabilities.Devices.Create.Preauthorized = true
-	nkr.Capabilities.Devices.Create.Tags = tags
-	jc, err := json.Marshal(nkr)
-	if err != nil {
-		return nil, err
-	}
-	req, err := http.NewRequestWithContext(ctx, "POST", fmt.Sprintf("https://unused/api/v2/tailnet/%s/keys", a.tsClient.Tailnet()), bytes.NewReader(jc))
-	if err != nil {
-		return nil, err
+func (a *ServiceReconciler) newAuthKey(ctx context.Context, tags []string) (string, error) {
+	caps := tailscale.KeyCapabilities{
+		Devices: tailscale.KeyDeviceCapabilities{
+			Create: tailscale.KeyDeviceCreateCapabilities{
+				Reusable:      false,
+				Preauthorized: true,
+				Tags:          tags,
+			},
+		},
 	}
-	resp, err := a.tsClient.Do(req)
+	key, _, err := a.tsClient.CreateKey(ctx, caps)
 	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-	slurp := new(bytes.Buffer)
-	if _, err := io.Copy(slurp, resp.Body); err != nil {
-		return nil, err
-	}
-	if resp.StatusCode != http.StatusOK {
-		return nil, fmt.Errorf("unexpected status code: %d; %v", resp.StatusCode, slurp.String())
-	}
-	var ak authKey
-	if err := json.NewDecoder(slurp).Decode(&ak); err != nil {
-		return nil, err
+		return "", err
 	}
-	return &ak, nil
+	return key, nil
 }
 
 //go:embed manifests/proxy.yaml