feat: switch away from websocket to stdout messaging for agent

agent/internal/tsnet/server.go

@@ -2,6 +2,9 @@ package tsnet
 
 import (
 	"context"
+	"os"
+	"path/filepath"
+
 	"github.com/tale/headplane/agent/internal/config"
 	"github.com/tale/headplane/agent/internal/util"
 	"tailscale.com/client/tailscale"
@@ -17,15 +20,27 @@ type TSAgent struct {
 
 // Creates a new tsnet agent and returns an instance of the server.
 func NewAgent(cfg *config.Config) *TSAgent {
+	log := util.GetLogger()
+
+	dir, err := filepath.Abs(cfg.WorkDir)
+	if err != nil {
+		log.Fatal("Failed to get absolute path: %s", err)
+	}
+
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		log.Fatal("Cannot create agent work directory: %s", err)
+	}
+
 	server := &tsnet.Server{
+		Dir:        dir,
 		Hostname:   cfg.Hostname,
 		ControlURL: cfg.TSControlURL,
 		AuthKey:    cfg.TSAuthKey,
-		Logf:       func(string, ...interface{}) {}, // Disabled by default
+		Logf:       func(string, ...any) {}, // Disabled by default
+		UserLogf:   log.Info,
 	}
 
 	if cfg.Debug {
-		log := util.GetLogger()
 		server.Logf = log.Debug
 	}
 
@@ -47,8 +62,13 @@ func (s *TSAgent) Connect() {
 		log.Fatal("Failed to initialize local Tailscale client: %s", err)
 	}
 
+	id, err := status.Self.PublicKey.MarshalText()
+	if err != nil {
+		log.Fatal("Failed to marshal public key: %s", err)
+	}
+
 	log.Info("Connected to Tailnet (PublicKey: %s)", status.Self.PublicKey)
-	s.ID = string(status.Self.ID)
+	s.ID = string(id)
 }
 
 // Shuts down the tsnet agent.