feat: create initial agent for localapi

agent/cmd/hp_agent/hp_agent.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	_ "github.com/joho/godotenv/autoload"
+	"github.com/tale/headplane/agent/config"
+	"github.com/tale/headplane/agent/tsnet"
+	"github.com/tale/headplane/agent/hpagent"
+	"log"
+)
+
+func main() {
+	cfg, err := config.Load()
+	if err != nil {
+		log.Fatalf("Failed to load configuration: %s", err)
+	}
+
+	agent := tsnet.NewAgent(
+		cfg.Hostname,
+		cfg.TSControlURL,
+		cfg.TSAuthKey,
+		cfg.Debug,
+	)
+
+	agent.StartAndFetchID()
+	defer agent.Shutdown()
+
+	ws, err := hpagent.NewSocket(agent, cfg.HPControlURL, cfg.Debug)
+	if err != nil {
+		log.Fatalf("Failed to create websocket: %s", err)
+	}
+
+	defer ws.StopListening()
+	ws.StartListening()
+}

agent/config/config.go

@@ -0,0 +1,52 @@
+package config
+
+import (
+	_ "github.com/joho/godotenv/autoload"
+	"os"
+)
+
+// Config represents the configuration for the agent.
+type Config struct {
+	Debug        bool
+	Hostname     string
+	TSControlURL string
+	TSAuthKey    string
+	HPControlURL string
+}
+
+const (
+	DebugEnv        = "HP_AGENT_DEBUG"
+	HostnameEnv     = "HP_AGENT_HOSTNAME"
+	TSControlURLEnv = "HP_AGENT_TS_SERVER"
+	TSAuthKeyEnv    = "HP_AGENT_TS_AUTHKEY"
+	HPControlURLEnv = "HP_AGENT_HP_SERVER"
+)
+
+// Load reads the agent configuration from environment variables.
+func Load() (*Config, error) {
+	c := &Config{
+		Debug:        false,
+		Hostname:     os.Getenv(HostnameEnv),
+		TSControlURL: os.Getenv(TSControlURLEnv),
+		TSAuthKey:    os.Getenv(TSAuthKeyEnv),
+		HPControlURL: os.Getenv(HPControlURLEnv),
+	}
+
+	if os.Getenv(DebugEnv) == "true" {
+		c.Debug = true
+	}
+
+	if err := validateRequired(c); err != nil {
+		return nil, err
+	}
+
+	if err := validateTSReady(c); err != nil {
+		return nil, err
+	}
+
+	if err := validateHPReady(c); err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}

agent/config/preflight.go

@@ -0,0 +1,68 @@
+package config
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+// Checks to make sure all required environment variables are set
+func validateRequired(config *Config) error {
+	if config.Hostname == "" {
+		return fmt.Errorf("%s is required", HostnameEnv)
+	}
+
+	if config.TSControlURL == "" {
+		return fmt.Errorf("%s is required", TSControlURLEnv)
+	}
+
+	if config.HPControlURL == "" {
+		return fmt.Errorf("%s is required", HPControlURLEnv)
+	}
+
+	if config.TSAuthKey == "" {
+		return fmt.Errorf("%s is required", TSAuthKeyEnv)
+	}
+
+	return nil
+}
+
+// Pings the Tailscale control server to make sure it's up and running
+func validateTSReady(config *Config) error {
+	testURL := config.TSControlURL
+	if strings.HasSuffix(testURL, "/") {
+		testURL = testURL[:len(testURL)-1]
+	}
+
+	testURL = fmt.Sprintf("%s/key?v=109", testURL)
+	resp, err := http.Get(testURL)
+	if err != nil {
+		return fmt.Errorf("Failed to connect to TS control server: %s", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("Failed to connect to TS control server: %s", resp.Status)
+	}
+
+	return nil
+}
+
+// Pings the Headplane server to make sure it's up and running
+func validateHPReady(config *Config) error {
+	testURL := config.HPControlURL
+	if strings.HasSuffix(testURL, "/") {
+		testURL = testURL[:len(testURL)-1]
+	}
+
+	testURL = fmt.Sprintf("%s/healthz", testURL)
+	resp, err := http.Get(testURL)
+	if err != nil {
+		return fmt.Errorf("Failed to connect to HP control server: %s", err)
+	}
+
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("Failed to connect to HP control server: %s", resp.Status)
+	}
+
+	return nil
+}

agent/hpagent/handler.go

@@ -0,0 +1,83 @@
+package hpagent
+
+import (
+	"encoding/json"
+	"log"
+	"sync"
+	"tailscale.com/tailcfg"
+)
+
+// Represents messages from the Headplane master
+type RecvMessage struct {
+	NodeIDs []string `json:omitempty`
+}
+
+// Starts listening for messages from the Headplane master
+func (s *Socket) StartListening() {
+	for {
+		_, message, err := s.ReadMessage()
+		if err != nil {
+			log.Printf("error reading message: %v", err)
+			return
+		}
+
+		var msg RecvMessage
+		err = json.Unmarshal(message, &msg)
+		if err != nil {
+			log.Printf("error unmarshalling message: %v", err)
+			continue
+		}
+
+		if s.Debug {
+			log.Printf("got message: %s", message)
+		}
+
+		if len(msg.NodeIDs) == 0 {
+			log.Printf("got a message with no node IDs? %s", message)
+			continue
+		}
+
+		// Accumulate the results since we invoke via gofunc
+		results := make(map[string]*tailcfg.HostinfoView)
+		mu := sync.Mutex{}
+		wg := sync.WaitGroup{}
+
+		for _, nodeID := range msg.NodeIDs {
+			wg.Add(1)
+			go func(nodeID string) {
+				defer wg.Done()
+				result, err := s.Agent.GetStatusForPeer(nodeID)
+				if err != nil {
+					log.Printf("error getting status: %v", err)
+					return
+				}
+
+				if result == nil {
+					return
+				}
+
+				mu.Lock()
+				results[nodeID] = result
+				mu.Unlock()
+			}(nodeID)
+		}
+
+		wg.Wait()
+
+		// Send the results back to the Headplane master
+		err = s.SendStatus(results)
+		if err != nil {
+			log.Printf("error sending status: %v", err)
+			return
+		}
+
+		if s.Debug {
+			log.Printf("sent status: %s", results)
+		}
+	}
+}
+
+// Stops listening for messages from the Headplane master
+func (s *Socket) StopListening() {
+	s.Close()
+}

agent/hpagent/sender.go

@@ -0,0 +1,11 @@
+package hpagent
+
+import (
+	"tailscale.com/tailcfg"
+)
+
+// Sends the status to the Headplane master
+func (s *Socket) SendStatus(status map[string]*tailcfg.HostinfoView) error {
+	err := s.WriteJSON(status)
+	return err
+}

agent/hpagent/websocket.go

@@ -0,0 +1,53 @@
+package hpagent
+
+import (
+	"fmt"
+	"github.com/gorilla/websocket"
+	"github.com/tale/headplane/agent/tsnet"
+	"log"
+	"net/http"
+	"net/url"
+)
+
+type Socket struct {
+	*websocket.Conn
+	Debug bool
+	Agent *tsnet.TSAgent
+}
+
+// Creates a new websocket connection to the Headplane server.
+func NewSocket(agent *tsnet.TSAgent, controlURL string, debug bool) (*Socket, error) {
+	wsURL, err := httpToWs(controlURL)
+	if err != nil {
+		return nil, err
+	}
+
+	headers := http.Header{}
+	headers.Add("X-Headplane-TS-Node-ID", agent.ID)
+
+	log.Printf("dialing websocket at %s", wsURL)
+	ws, _, err := websocket.DefaultDialer.Dial(wsURL, headers)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Socket{ws, debug, agent}, nil
+}
+
+// We need to convert the control URL to a websocket URL
+func httpToWs(controlURL string) (string, error) {
+	u, err := url.Parse(controlURL)
+	if err != nil {
+		return "", err
+	}
+
+	if u.Scheme == "http" {
+		u.Scheme = "ws"
+	} else if u.Scheme == "https" {
+		u.Scheme = "wss"
+	} else {
+		return "", fmt.Errorf("unsupported scheme: %s", u.Scheme)
+	}
+
+	return u.String(), nil
+}

agent/tsnet/peers.go

@@ -0,0 +1,42 @@
+package tsnet
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"strings"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/key"
+
+	"go4.org/mem"
+)
+
+// Returns the raw hostinfo for a peer based on node ID.
+func (s *TSAgent) GetStatusForPeer(id string) (*tailcfg.HostinfoView, error) {
+	if !strings.HasPrefix(id, "nodekey:") {
+		return nil, fmt.Errorf("invalid node ID")
+	}
+
+	if s.Debug {
+		log.Printf("querying peer state for %s", id)
+	}
+
+	status, err := s.Lc.Status(context.Background())
+	if err != nil {
+		return nil, fmt.Errorf("failed to get status: %w", err)
+	}
+
+	nodeKey, err := key.ParseNodePublicUntyped(mem.S(id[8:]))
+	peer := status.Peer[nodeKey]
+	if peer == nil {
+		return nil, nil
+	}
+
+	ip := peer.TailscaleIPs[0].String()
+	whois, err := s.Lc.WhoIs(context.Background(), ip)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get whois: %w", err)
+	}
+
+	return &whois.Node.Hostinfo, nil
+}

agent/tsnet/server.go

@@ -0,0 +1,61 @@
+package tsnet
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+
+	"tailscale.com/client/tailscale"
+	"tailscale.com/tsnet"
+)
+
+// Wrapper type so we can add methods to the server.
+type TSAgent struct {
+	*tsnet.Server
+	Lc *tailscale.LocalClient
+	ID string
+	Debug bool
+}
+
+// Creates a new tsnet agent and returns an instance of the server.
+func NewAgent(hostname, controlURL, authKey string, debug bool) *TSAgent {
+	s := &tsnet.Server{
+		Hostname:   hostname,
+		ControlURL: controlURL,
+		AuthKey:    authKey,
+		Logf:       func(string, ...interface{}) {}, // Disabled by default
+	}
+
+	if debug {
+		s.Logf = log.New(
+			os.Stderr,
+			fmt.Sprintf("[DBG:%s] ", hostname),
+			log.LstdFlags,
+		).Printf
+	}
+
+	return &TSAgent{s, nil, "", debug}
+}
+
+// Starts the tsnet agent and sets the node ID.
+func (s *TSAgent) StartAndFetchID() {
+	// Waits until the agent is up and running.
+	status, err := s.Up(context.Background())
+	if err != nil {
+		log.Fatalf("Failed to start agent: %v", err)
+	}
+
+	s.Lc, err = s.LocalClient()
+	if err != nil {
+		log.Fatalf("Failed to create local client: %v", err)
+	}
+
+	log.Printf("Agent running with ID: %s", status.Self.PublicKey)
+	s.ID = string(status.Self.ID)
+}
+
+// Shuts down the tsnet agent.
+func (s *TSAgent) Shutdown() {
+	s.Close()
+}