feat: use a debug logger for agent

agent/internal/config/config.go

@@ -0,0 +1,52 @@
+package config
+
+import "os"
+
+// Config represents the configuration for the agent.
+type Config struct {
+	Debug        bool
+	Hostname     string
+	TSControlURL string
+	TSAuthKey    string
+	HPControlURL string
+	HPAuthKey    string
+}
+
+const (
+	DebugEnv        = "HEADPLANE_AGENT_DEBUG"
+	HostnameEnv     = "HEADPLANE_AGENT_HOSTNAME"
+	TSControlURLEnv = "HEADPLANE_AGENT_TS_SERVER"
+	TSAuthKeyEnv    = "HEADPLANE_AGENT_TS_AUTHKEY"
+	HPControlURLEnv = "HEADPLANE_AGENT_HP_SERVER"
+	HPAuthKeyEnv    = "HEADPLANE_AGENT_HP_AUTHKEY"
+)
+
+// 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),
+		HPAuthKey:    os.Getenv(HPAuthKeyEnv),
+	}
+
+	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/internal/config/preflight.go

@@ -0,0 +1,72 @@
+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)
+	}
+
+	if config.HPAuthKey == "" {
+		return fmt.Errorf("%s is required", HPAuthKeyEnv)
+	}
+
+	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/health", 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/internal/hpagent/handler.go

@@ -0,0 +1,84 @@
+package hpagent
+
+import (
+	"encoding/json"
+	"sync"
+
+	"github.com/tale/headplane/agent/internal/util"
+	"tailscale.com/tailcfg"
+)
+
+// Represents messages from the Headplane master
+type RecvMessage struct {
+	NodeIDs []string
+}
+
+// Starts listening for messages from the Headplane master
+func (s *Socket) FollowMaster() {
+	log := util.GetLogger()
+
+	for {
+		_, message, err := s.ReadMessage()
+		if err != nil {
+			log.Error("Error reading message: %s", err)
+			return
+		}
+
+		var msg RecvMessage
+		err = json.Unmarshal(message, &msg)
+		if err != nil {
+			log.Error("Unable to unmarshal message: %s", err)
+			log.Debug("Full Error: %v", err)
+			continue
+		}
+
+		log.Debug("Recieved message from master: %v", message)
+
+		if len(msg.NodeIDs) == 0 {
+			log.Debug("Message recieved had no node IDs")
+			log.Debug("Full message: %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.Error("Unable to get status for node %s: %s", nodeID, err)
+					return
+				}
+
+				if result == nil {
+					log.Debug("No status for node %s", nodeID)
+					return
+				}
+
+				mu.Lock()
+				results[nodeID] = result
+				mu.Unlock()
+			}(nodeID)
+		}
+
+		wg.Wait()
+
+		// Send the results back to the Headplane master
+		log.Debug("Sending status back to master: %v", results)
+		err = s.SendStatus(results)
+		if err != nil {
+			log.Error("Error sending status: %s", err)
+			return
+		}
+	}
+}
+
+// Stops listening for messages from the Headplane master
+func (s *Socket) StopListening() {
+	s.Close()
+}

agent/internal/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/internal/hpagent/websocket.go

@@ -0,0 +1,67 @@
+package hpagent
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/gorilla/websocket"
+	"github.com/tale/headplane/agent/internal/config"
+	"github.com/tale/headplane/agent/internal/tsnet"
+	"github.com/tale/headplane/agent/internal/util"
+)
+
+type Socket struct {
+	*websocket.Conn
+	Agent *tsnet.TSAgent
+}
+
+// Creates a new websocket connection to the Headplane server.
+func NewSocket(agent *tsnet.TSAgent, cfg *config.Config) (*Socket, error) {
+	log := util.GetLogger()
+
+	wsURL, err := httpToWs(cfg.HPControlURL)
+	if err != nil {
+		return nil, err
+	}
+
+	headers := http.Header{}
+	headers.Add("X-Headplane-Tailnet-ID", agent.ID)
+	auth := fmt.Sprintf("Bearer %s", cfg.HPAuthKey)
+	headers.Add("Authorization", auth)
+
+	log.Info("Dialing WebSocket with master: %s", wsURL)
+	ws, _, err := websocket.DefaultDialer.Dial(wsURL, headers)
+	if err != nil {
+		log.Debug("Failed to dial WebSocket: %s", err)
+		return nil, err
+	}
+
+	return &Socket{ws, agent}, nil
+}
+
+// We need to convert the control URL to a websocket URL
+func httpToWs(controlURL string) (string, error) {
+	log := util.GetLogger()
+	u, err := url.Parse(controlURL)
+	if err != nil {
+		log.Debug("Failed to parse control URL: %s", err)
+		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)
+	}
+
+	// We also need to append /_dial to the path
+	if u.Path[len(u.Path)-1] != '/' {
+		u.Path += "/"
+	}
+
+	u.Path += "_dial"
+	return u.String(), nil
+}

agent/internal/tsnet/peers.go

@@ -0,0 +1,66 @@
+package tsnet
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"strings"
+
+	"github.com/tale/headplane/agent/internal/util"
+	"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) {
+	log := util.GetLogger()
+
+	if !strings.HasPrefix(id, "nodekey:") {
+		log.Debug("Node ID with missing prefix: %s", id)
+		return nil, fmt.Errorf("invalid node ID: %s", id)
+	}
+
+	log.Debug("Querying status of peer: %s", id)
+	status, err := s.Lc.Status(context.Background())
+	if err != nil {
+		log.Debug("Failed to get status: %s", err)
+		return nil, fmt.Errorf("failed to get status: %w", err)
+	}
+
+	// We need to convert from 64 char hex to 32 byte raw.
+	bytes, err := hex.DecodeString(id[8:])
+	if err != nil {
+		log.Debug("Failed to decode hex: %s", err)
+		return nil, fmt.Errorf("failed to decode hex: %w", err)
+	}
+
+	raw := mem.B(bytes)
+	if raw.Len() != 32 {
+		log.Debug("Invalid node ID length: %d", raw.Len())
+		return nil, fmt.Errorf("invalid node ID length: %d", raw.Len())
+	}
+
+	nodeKey := key.NodePublicFromRaw32(raw)
+	peer := status.Peer[nodeKey]
+	if peer == nil {
+		// Check if we are on Self.
+		if status.Self.PublicKey == nodeKey {
+			peer = status.Self
+		} else {
+			log.Debug("Peer not found in status: %s", id)
+			return nil, nil
+		}
+	}
+
+	ip := peer.TailscaleIPs[0].String()
+	whois, err := s.Lc.WhoIs(context.Background(), ip)
+	if err != nil {
+		log.Debug("Failed to get whois: %s", err)
+		return nil, fmt.Errorf("failed to get whois: %w", err)
+	}
+
+	log.Debug("Got whois for peer %s: %v", id, whois)
+	return &whois.Node.Hostinfo, nil
+}

agent/internal/tsnet/server.go

@@ -0,0 +1,57 @@
+package tsnet
+
+import (
+	"context"
+	"github.com/tale/headplane/agent/internal/config"
+	"github.com/tale/headplane/agent/internal/util"
+	"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
+}
+
+// Creates a new tsnet agent and returns an instance of the server.
+func NewAgent(cfg *config.Config) *TSAgent {
+	server := &tsnet.Server{
+		Hostname:   cfg.Hostname,
+		ControlURL: cfg.TSControlURL,
+		AuthKey:    cfg.TSAuthKey,
+		Logf:       func(string, ...interface{}) {}, // Disabled by default
+	}
+
+	if cfg.Debug {
+		log := util.GetLogger()
+		server.Logf = log.Debug
+	}
+
+	return &TSAgent{server, nil, ""}
+}
+
+// Starts the tsnet agent and sets the node ID.
+func (s *TSAgent) Connect() {
+	log := util.GetLogger()
+
+	// Waits until the agent is up and running.
+	status, err := s.Up(context.Background())
+	if err != nil {
+		log.Fatal("Failed to connect to Tailnet: %s", err)
+	}
+
+	s.Lc, err = s.LocalClient()
+	if err != nil {
+		log.Fatal("Failed to initialize local Tailscale client: %s", err)
+	}
+
+	log.Info("Connected to Tailnet (PublicKey: %s)", status.Self.PublicKey)
+	s.ID = string(status.Self.ID)
+}
+
+// Shuts down the tsnet agent.
+func (s *TSAgent) Shutdown() {
+	s.Close()
+}

agent/internal/util/logger.go

@@ -0,0 +1,66 @@
+package util
+
+import (
+	"log"
+	"os"
+	"sync"
+)
+
+type Logger struct {
+	debug *log.Logger
+	info  *log.Logger
+	error *log.Logger
+}
+
+var lock = &sync.Mutex{}
+var logger *Logger
+
+func GetLogger() *Logger {
+	if logger == nil {
+		lock.Lock()
+		defer lock.Unlock()
+		if logger == nil {
+			logger = NewLogger()
+		}
+	}
+
+	return logger
+}
+
+func NewLogger() *Logger {
+	// Create a new Logger for stdout and stderr
+	// Errors still go to both stdout and stderr
+	return &Logger{
+		debug: nil,
+		info:  log.New(os.Stdout, "[INFO] ", log.LstdFlags),
+		error: log.New(os.Stderr, "[ERROR] ", log.LstdFlags),
+	}
+}
+
+func (logger *Logger) SetDebug(debug bool) {
+	if debug {
+		logger.Info("Enabling Debug logging for headplane-agent")
+		logger.Info("Be careful, this will spam a lot of information")
+		logger.debug = log.New(os.Stdout, "[DEBUG] ", log.LstdFlags)
+	} else {
+		logger.debug = nil
+	}
+}
+
+func (logger *Logger) Info(fmt string, v ...any) {
+	logger.info.Printf(fmt, v...)
+}
+
+func (logger *Logger) Debug(fmt string, v ...any) {
+	if logger.debug != nil {
+		logger.debug.Printf(fmt, v...)
+	}
+}
+
+func (logger *Logger) Error(fmt string, v ...any) {
+	logger.error.Printf(fmt, v...)
+}
+
+func (logger *Logger) Fatal(fmt string, v ...any) {
+	logger.error.Fatalf(fmt, v...)
+}