client/tailscale,cmd/k8s-operator,internal/client/tailscale: move VIP service client methods into internal control client

Updates tailscale/corp#22748

Signed-off-by: Percy Wegmann <percy@tailscale.com>

internal/client/tailscale/tailscale.go

@@ -8,9 +8,16 @@
 package tailscale
 
 import (
+	"errors"
+	"io"
+	"net/http"
+
 	tsclient "tailscale.com/client/tailscale"
 )
 
+// maxSize is the maximum read size (10MB) of responses from the server.
+const maxReadSize = 10 << 20
+
 func init() {
 	tsclient.I_Acknowledge_This_API_Is_Unstable = true
 }
@@ -50,3 +57,27 @@ func NewClient(tailnet string, auth AuthMethod) *Client {
 type Client struct {
 	*tsclient.Client
 }
+
+// HandleErrorResponse is an alias to tailscale.com/client/tailscale.
+func HandleErrorResponse(b []byte, resp *http.Response) error {
+	return tsclient.HandleErrorResponse(b, resp)
+}
+
+// SendRequest add the authentication key to the request and sends it. It
+// receives the response and reads up to 10MB of it.
+func SendRequest(c *Client, req *http.Request) ([]byte, *http.Response, error) {
+	resp, err := c.Do(req)
+	if err != nil {
+		return nil, resp, err
+	}
+	defer resp.Body.Close()
+
+	// Read response. Limit the response to 10MB.
+	// This limit is carried over from client/tailscale/tailscale.go.
+	body := io.LimitReader(resp.Body, maxReadSize+1)
+	b, err := io.ReadAll(body)
+	if len(b) > maxReadSize {
+		err = errors.New("API response too large")
+	}
+	return b, resp, err
+}

internal/client/tailscale/vip_service.go

@@ -0,0 +1,103 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package tailscale
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/httpm"
+)
+
+// VIPService is a Tailscale VIPService with Tailscale API JSON representation.
+type VIPService struct {
+	// Name is a VIPService name in form svc:<leftmost-label-of-service-DNS-name>.
+	Name tailcfg.ServiceName `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"`
+}
+
+// GetVIPService retrieves a VIPService by its name. It returns 404 if the VIPService is not found.
+func (client *Client) GetVIPService(ctx context.Context, name tailcfg.ServiceName) (*VIPService, error) {
+	path := client.BuildTailnetURL("vip-services", name.String())
+	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 := SendRequest(client, 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
+}
+
+// CreateOrUpdateVIPService 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 (client *Client) CreateOrUpdateVIPService(ctx context.Context, svc *VIPService) error {
+	data, err := json.Marshal(svc)
+	if err != nil {
+		return err
+	}
+	path := client.BuildTailnetURL("vip-services", svc.Name.String())
+	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 := SendRequest(client, 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
+}
+
+// DeleteVIPService deletes a VIPService by its name. It returns an error if the VIPService
+// does not exist or if the deletion fails.
+func (client *Client) DeleteVIPService(ctx context.Context, name tailcfg.ServiceName) error {
+	path := client.BuildTailnetURL("vip-services", name.String())
+	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 := SendRequest(client, 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
+}