feat: add comprehensive node cleanup system

Implements automated cleanup workflow when nodes are deleted from Pulse, removing all monitoring footprint from the host. Changes include a new RPC handler in the sensor proxy for cleanup requests, enhanced node deletion modal with detailed cleanup explanations, and improved SSH key management with proper tagging for atomic updates.

cmd/pulse-sensor-proxy/cleanup.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/rs/zerolog"
+)
+
+const cleanupRequestFilename = "cleanup-request.json"
+
+func (p *Proxy) cleanupRequestPath() (string, error) {
+	workDir := p.workDir
+	if workDir == "" {
+		workDir = defaultWorkDir()
+	}
+
+	if workDir == "" {
+		return "", errors.New("cleanup working directory not configured")
+	}
+
+	return filepath.Join(workDir, cleanupRequestFilename), nil
+}
+
+func (p *Proxy) handleRequestCleanup(ctx context.Context, req *RPCRequest, logger zerolog.Logger) (interface{}, error) {
+	cleanupPath, err := p.cleanupRequestPath()
+	if err != nil {
+		return nil, err
+	}
+
+	dir := filepath.Dir(cleanupPath)
+	if err := os.MkdirAll(dir, 0o750); err != nil {
+		return nil, fmt.Errorf("ensure cleanup directory: %w", err)
+	}
+
+	payload := map[string]any{
+		"requestedAt": time.Now().UTC().Format(time.RFC3339),
+	}
+	if req != nil && req.Params != nil {
+		if host, ok := req.Params["host"].(string); ok && host != "" {
+			payload["host"] = host
+		}
+		if reason, ok := req.Params["reason"].(string); ok && reason != "" {
+			payload["reason"] = reason
+		}
+	}
+
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("encode cleanup payload: %w", err)
+	}
+
+	tmpFile, err := os.CreateTemp(dir, "cleanup-request-*.tmp")
+	if err != nil {
+		return nil, fmt.Errorf("prepare cleanup signal: %w", err)
+	}
+	tmpName := tmpFile.Name()
+	if _, err := tmpFile.Write(append(data, '\n')); err != nil {
+		tmpFile.Close()
+		os.Remove(tmpName)
+		return nil, fmt.Errorf("write cleanup payload: %w", err)
+	}
+	if err := tmpFile.Chmod(0o600); err != nil {
+		logger.Warn().Err(err).Str("path", tmpName).Msg("Failed to set cleanup payload permissions")
+	}
+	if err := tmpFile.Close(); err != nil {
+		os.Remove(tmpName)
+		return nil, fmt.Errorf("close cleanup payload: %w", err)
+	}
+
+	// Replace any existing request atomically so systemd path units trigger on change.
+	if err := os.Rename(tmpName, cleanupPath); err != nil {
+		os.Remove(tmpName)
+		return nil, fmt.Errorf("activate cleanup payload: %w", err)
+	}
+
+	logger.Info().
+		Str("path", cleanupPath).
+		Interface("payload", payload).
+		Msg("Cleanup request signalled")
+
+	return map[string]any{"queued": true}, nil
+}

cmd/pulse-sensor-proxy/main.go

@@ -35,6 +35,10 @@ const (
 	maxRequestBytes   = 16 * 1024 // 16 KiB max request size
 )
 
+func defaultWorkDir() string {
+	return "/var/lib/pulse-sensor-proxy"
+}
+
 var rootCmd = &cobra.Command{
 	Use:     "pulse-sensor-proxy",
 	Short:   "Pulse Sensor Proxy - Secure sensor data bridge for containerized Pulse",
@@ -74,6 +78,7 @@ func main() {
 type Proxy struct {
 	socketPath  string
 	sshKeyPath  string
+	workDir     string
 	listener    net.Listener
 	rateLimiter *rateLimiter
 	nodeGate    *nodeGate
@@ -93,6 +98,7 @@ const (
 	RPCRegisterNodes     = "register_nodes"
 	RPCGetTemperature    = "get_temperature"
 	RPCGetStatus         = "get_status"
+	RPCRequestCleanup    = "request_cleanup"
 )
 
 // RPCRequest represents a request from Pulse
@@ -158,12 +164,20 @@ func runProxy() {
 		metrics:     metrics,
 	}
 
+	if wd, err := os.Getwd(); err == nil {
+		proxy.workDir = wd
+	} else {
+		log.Warn().Err(err).Msg("Failed to determine working directory; using default")
+		proxy.workDir = defaultWorkDir()
+	}
+
 	// Register RPC method handlers
 	proxy.router = map[string]handlerFunc{
 		RPCGetStatus:         proxy.handleGetStatusV2,
 		RPCEnsureClusterKeys: proxy.handleEnsureClusterKeysV2,
 		RPCRegisterNodes:     proxy.handleRegisterNodesV2,
 		RPCGetTemperature:    proxy.handleGetTemperatureV2,
+		RPCRequestCleanup:    proxy.handleRequestCleanup,
 	}
 
 	if err := proxy.initAuthRules(); err != nil {

cmd/pulse-sensor-proxy/ssh.go

@@ -136,7 +136,7 @@ func (p *Proxy) testSSHConnection(nodeHost string) error {
 
 	privKeyPath := filepath.Join(p.sshKeyPath, "id_ed25519")
 	cmd := fmt.Sprintf(
-		`ssh -i %s -o StrictHostKeyChecking=no -o ConnectTimeout=5 root@%s "echo test"`,
+		`ssh -i %[1]s -T -n -o BatchMode=yes -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -o ConnectTimeout=5 root@%[2]s "echo test"`,
 		privKeyPath,
 		nodeHost,
 	)
@@ -166,7 +166,7 @@ func (p *Proxy) getTemperatureViaSSH(nodeHost string) (string, error) {
 	// Since we use ForceCommand="sensors -j", any SSH command will run sensors
 	// We don't need to specify the command
 	cmd := fmt.Sprintf(
-		`ssh -i %s -o StrictHostKeyChecking=no -o ConnectTimeout=5 root@%s ""`,
+		`ssh -i %[1]s -T -n -o BatchMode=yes -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -o ConnectTimeout=5 root@%[2]s ""`,
 		privKeyPath,
 		nodeHost,
 	)