cmd/{k8s-operator,containerboot},kube/kubetypes: parse Ingresses for ingress ProxyGroup (#14583)

cmd/k8s-operator: add logic to parse L7 Ingresses in HA mode

- Wrap the Tailscale API client used by the Kubernetes Operator
into a client that knows how to manage VIPServices.
- Create/Delete VIPServices and update serve config for L7 Ingresses
for ProxyGroup.
- Ensure that ingress ProxyGroup proxies mount serve config from a shared ConfigMap.

Updates tailscale/corp#24795


Signed-off-by: Irbe Krumina <irbe@tailscale.com>

cmd/k8s-operator/tsclient.go

@@ -0,0 +1,185 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !plan9
+
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+
+	"golang.org/x/oauth2/clientcredentials"
+	"tailscale.com/client/tailscale"
+	"tailscale.com/util/httpm"
+)
+
+// defaultTailnet is a value that can be used in Tailscale API calls instead of tailnet name to indicate that the API
+// call should be performed on the default tailnet for the provided credentials.
+const (
+	defaultTailnet = "-"
+	defaultBaseURL = "https://api.tailscale.com"
+)
+
+func newTSClient(ctx context.Context, clientIDPath, clientSecretPath string) (tsClient, error) {
+	clientID, err := os.ReadFile(clientIDPath)
+	if err != nil {
+		return nil, fmt.Errorf("error reading client ID %q: %w", clientIDPath, err)
+	}
+	clientSecret, err := os.ReadFile(clientSecretPath)
+	if err != nil {
+		return nil, fmt.Errorf("reading client secret %q: %w", clientSecretPath, err)
+	}
+	credentials := clientcredentials.Config{
+		ClientID:     string(clientID),
+		ClientSecret: string(clientSecret),
+		TokenURL:     "https://login.tailscale.com/api/v2/oauth/token",
+	}
+	c := tailscale.NewClient(defaultTailnet, nil)
+	c.UserAgent = "tailscale-k8s-operator"
+	c.HTTPClient = credentials.Client(ctx)
+	tsc := &tsClientImpl{
+		Client:  c,
+		baseURL: defaultBaseURL,
+		tailnet: defaultTailnet,
+	}
+	return tsc, nil
+}
+
+type tsClient interface {
+	CreateKey(ctx context.Context, caps tailscale.KeyCapabilities) (string, *tailscale.Key, error)
+	Device(ctx context.Context, deviceID string, fields *tailscale.DeviceFieldsOpts) (*tailscale.Device, error)
+	DeleteDevice(ctx context.Context, nodeStableID string) error
+	getVIPServiceByName(ctx context.Context, name string) (*VIPService, error)
+	createOrUpdateVIPServiceByName(ctx context.Context, svc *VIPService) error
+	deleteVIPServiceByName(ctx context.Context, name string) error
+}
+
+type tsClientImpl struct {
+	*tailscale.Client
+	baseURL string
+	tailnet string
+}
+
+// VIPService is a Tailscale VIPService with Tailscale API JSON representation.
+type VIPService struct {
+	// Name is the leftmost label of the DNS name of the VIP service.
+	// Name is required.
+	Name string `json:"name,omitempty"`
+	// Addrs are the IP addresses of the VIP Service. There are two addresses:
+	// the first is IPv4 and the second is IPv6.
+	// When creating a new VIP Service, the IP addresses are optional: if no
+	// addresses are specified then they will be selected. If an IPv4 address is
+	// specified at index 0, then that address will attempt to be used. An IPv6
+	// address can not be specified upon creation.
+	Addrs []string `json:"addrs,omitempty"`
+	// Comment is an optional text string for display in the admin panel.
+	Comment string `json:"comment,omitempty"`
+	// Ports are the ports of a VIPService that will be configured via Tailscale serve config.
+	// If set, any node wishing to advertise this VIPService must have this port configured via Tailscale serve.
+	Ports []string `json:"ports,omitempty"`
+	// Tags are optional ACL tags that will be applied to the VIPService.
+	Tags []string `json:"tags,omitempty"`
+}
+
+// GetVIPServiceByName retrieves a VIPService by its name. It returns 404 if the VIPService is not found.
+func (c *tsClientImpl) getVIPServiceByName(ctx context.Context, name string) (*VIPService, error) {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/by-name/%s", c.baseURL, c.tailnet, url.PathEscape(name))
+	req, err := http.NewRequestWithContext(ctx, httpm.GET, path, nil)
+	if err != nil {
+		return nil, fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return nil, fmt.Errorf("error making Tailsale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return nil, handleErrorResponse(b, resp)
+	}
+	svc := &VIPService{}
+	if err := json.Unmarshal(b, svc); err != nil {
+		return nil, err
+	}
+	return svc, nil
+}
+
+// CreateOrUpdateVIPServiceByName creates or updates a VIPService by its name. Caller must ensure that, if the
+// VIPService already exists, the VIPService is fetched first to ensure that any auto-allocated IP addresses are not
+// lost during the update. If the VIPService was created without any IP addresses explicitly set (so that they were
+// auto-allocated by Tailscale) any subsequent request to this function that does not set any IP addresses will error.
+func (c *tsClientImpl) createOrUpdateVIPServiceByName(ctx context.Context, svc *VIPService) error {
+	data, err := json.Marshal(svc)
+	if err != nil {
+		return err
+	}
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/by-name/%s", c.baseURL, c.tailnet, url.PathEscape(svc.Name))
+	req, err := http.NewRequestWithContext(ctx, httpm.PUT, path, bytes.NewBuffer(data))
+	if err != nil {
+		return fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return fmt.Errorf("error making Tailscale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	// TODO: Change the check for the StatusCode to include other 2XX success codes.
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+	return nil
+}
+
+// DeleteVIPServiceByName deletes a VIPService by its name. It returns an error if the VIPService
+// does not exist or if the deletion fails.
+func (c *tsClientImpl) deleteVIPServiceByName(ctx context.Context, name string) error {
+	path := fmt.Sprintf("%s/api/v2/tailnet/%s/vip-services/by-name/%s", c.baseURL, c.tailnet, url.PathEscape(name))
+	req, err := http.NewRequestWithContext(ctx, httpm.DELETE, path, nil)
+	if err != nil {
+		return fmt.Errorf("error creating new HTTP request: %w", err)
+	}
+	b, resp, err := c.sendRequest(req)
+	if err != nil {
+		return fmt.Errorf("error making Tailscale API request: %w", err)
+	}
+	// If status code was not successful, return the error.
+	if resp.StatusCode != http.StatusOK {
+		return handleErrorResponse(b, resp)
+	}
+	return nil
+}
+
+// sendRequest add the authentication key to the request and sends it. It
+// receives the response and reads up to 10MB of it.
+func (c *tsClientImpl) sendRequest(req *http.Request) ([]byte, *http.Response, error) {
+	resp, err := c.Do(req)
+	if err != nil {
+		return nil, resp, fmt.Errorf("error actually doing request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	// Read response
+	b, err := io.ReadAll(resp.Body)
+	if err != nil {
+		err = fmt.Errorf("error reading response body: %v", err)
+	}
+	return b, resp, err
+}
+
+// handleErrorResponse decodes the error message from the server and returns
+// an ErrResponse from it.
+func handleErrorResponse(b []byte, resp *http.Response) error {
+	var errResp tailscale.ErrResponse
+	if err := json.Unmarshal(b, &errResp); err != nil {
+		return err
+	}
+	errResp.Status = resp.StatusCode
+	return errResp
+}