Support Go agent side-by-side identity

agent/README.md

@@ -86,6 +86,21 @@ Run once against an existing config:
 ./tmp/rmm-agent-go -config /etc/rmm-agent.conf -once
 ```
 
+For side-by-side testing, use a separate config and hostname suffix so the Go preview enrolls as a separate device:
+
+```sh
+cp /etc/rmm-agent.conf /etc/rmm-agent-go.conf
+sed -i '/^DEVICE_ID=/d;/^DEVICE_TOKEN=/d' /etc/rmm-agent-go.conf
+cat >>/etc/rmm-agent-go.conf <<'EOF'
+HOSTNAME_SUFFIX="-go"
+LOCK_FILE="/tmp/rmm-agent-go.lock"
+SPOOL_DIR="/tmp/rmm-agent-go-results"
+BACKUP_DIR="/tmp/rmm-agent-go-backups"
+TUNNEL_STATE_DIR="/tmp/rmm-agent-go-tunnels"
+EOF
+./tmp/rmm-agent-go -config /etc/rmm-agent-go.conf -once
+```
+
 ## OpenWrt Package
 
 Package skeleton:

agent/go/cmd/rmm-agent/main.go

@@ -35,6 +35,8 @@ type config struct {
 	TunnelIdentity   string
 	TunnelStateDir   string
 	CheckTargets     []string
+	HostnameOverride string
+	HostnameSuffix   string
 	ConfigFile       string
 }
 
@@ -128,6 +130,8 @@ func loadConfig(path string) (config, error) {
 		TunnelIdentity:   envDefault("TUNNEL_IDENTITY_FILE", "/etc/rmm-agent/tunnel_key"),
 		TunnelStateDir:   envDefault("TUNNEL_STATE_DIR", "/tmp/rmm-agent-tunnels"),
 		CheckTargets:     splitWords(envDefault("CHECK_TARGETS", "1.1.1.1 8.8.8.8")),
+		HostnameOverride: os.Getenv("HOSTNAME_OVERRIDE"),
+		HostnameSuffix:   os.Getenv("HOSTNAME_SUFFIX"),
 		ConfigFile:       path,
 	}
 	data, err := os.ReadFile(path)
@@ -171,6 +175,12 @@ func loadConfig(path string) (config, error) {
 	if value := values["CHECK_TARGETS"]; value != "" {
 		cfg.CheckTargets = splitWords(value)
 	}
+	if value := values["HOSTNAME_OVERRIDE"]; value != "" {
+		cfg.HostnameOverride = value
+	}
+	if value := values["HOSTNAME_SUFFIX"]; value != "" {
+		cfg.HostnameSuffix = value
+	}
 	cfg.ServerURL = strings.TrimRight(cfg.ServerURL, "/")
 	if cfg.IntervalSeconds <= 0 {
 		cfg.IntervalSeconds = 30
@@ -205,6 +215,12 @@ func saveConfig(cfg config) error {
 	writeConfigLine(&b, "BACKUP_DIR", cfg.BackupDir)
 	writeConfigLine(&b, "TUNNEL_IDENTITY_FILE", cfg.TunnelIdentity)
 	writeConfigLine(&b, "TUNNEL_STATE_DIR", cfg.TunnelStateDir)
+	if cfg.HostnameOverride != "" {
+		writeConfigLine(&b, "HOSTNAME_OVERRIDE", cfg.HostnameOverride)
+	}
+	if cfg.HostnameSuffix != "" {
+		writeConfigLine(&b, "HOSTNAME_SUFFIX", cfg.HostnameSuffix)
+	}
 	writeConfigLine(&b, "DEVICE_ID", cfg.DeviceID)
 	writeConfigLine(&b, "DEVICE_TOKEN", cfg.DeviceToken)
 	tmp := cfg.ConfigFile + ".tmp"
@@ -228,7 +244,7 @@ func acquireLock(path string) (func(), error) {
 func enroll(ctx context.Context, client *http.Client, cfg *config) error {
 	body := map[string]string{
 		"enrollment_token": cfg.EnrollmentToken,
-		"hostname":         hostnameValue(),
+		"hostname":         cfg.displayHostname(),
 		"openwrt_version":  openwrtVersion(),
 	}
 	var resp enrollResponse
@@ -249,7 +265,7 @@ func heartbeatOnce(ctx context.Context, client *http.Client, cfg config) error {
 	}
 	body := map[string]any{
 		"device_id": cfg.DeviceID,
-		"inventory": buildInventory(),
+		"inventory": buildInventory(cfg),
 		"metrics":   buildMetrics(cfg.CheckTargets),
 	}
 	var resp heartbeatResponse
@@ -262,9 +278,9 @@ func heartbeatOnce(ctx context.Context, client *http.Client, cfg config) error {
 	return nil
 }
 
-func buildInventory() map[string]any {
+func buildInventory(cfg config) map[string]any {
 	return map[string]any{
-		"hostname":        hostnameValue(),
+		"hostname":        cfg.displayHostname(),
 		"openwrt_version": openwrtVersion(),
 		"agent_version":   agentVersion,
 		"agent_runtime":   "go",
@@ -277,6 +293,13 @@ func buildInventory() map[string]any {
 	}
 }
 
+func (cfg config) displayHostname() string {
+	if strings.TrimSpace(cfg.HostnameOverride) != "" {
+		return strings.TrimSpace(cfg.HostnameOverride)
+	}
+	return hostnameValue() + strings.TrimSpace(cfg.HostnameSuffix)
+}
+
 func buildMetrics(targets []string) map[string]any {
 	return map[string]any{
 		"system":              jsonObjectOrEmpty(commandOutput("ubus", "call", "system", "info")),