v0.5.5.3: wake drives on first poll for SMART baseline

On agent startup, the first poll skips the -n standby flag so smartctl
wakes all drives and reads full SMART data. This ensures every drive is
registered with its serial-based ID immediately. Subsequent polls honor
standby mode normally.

Fixes drives being silently dropped when sleeping on first scan after
agent startup.

Ref: #18 (rolandg-reflow)

Author: DAB-LABS

CHANGELOG.md

@@ -2,6 +2,15 @@
 
 All notable changes to SMART Sniffer are documented here.
 
+## v0.5.5.3 -- 2026-04-25
+
+Agent-only patch. No integration, installer, or config changes.
+
+Fixes drives being silently dropped when sleeping on agent startup, reported by @rolandg-reflow in [#18](https://github.com/DAB-LABS/smart-sniffer/issues/18).
+
+### Fixed
+- **Drives no longer vanish when sleeping on startup** -- the agent's first poll after starting now wakes all drives to collect a full SMART baseline (serial, model, attributes). This ensures every drive is registered with its stable serial-based ID immediately. Subsequent polls honor `standby_mode` normally -- sleeping drives are skipped and cached data is served. Previously, a drive that was asleep on the first poll was silently dropped from the API because there was no cached data to serve.
+
 ## v0.5.5.2 -- 2026-04-25
 
 Agent-only patch. No integration, installer, or config changes.

agent/main.go

@@ -613,10 +613,11 @@ func (dc *DriveCache) Refresh() {
 	// sleeping drives. Fall back to --scan if --scan-open is unsupported.
 	scanCmd := "--scan"
 	dc.mu.Lock()
+	isFirstPoll := dc.firstPoll
 	if dc.firstPoll {
 		scanCmd = "--scan-open"
 		dc.firstPoll = false
-		log.Println("first poll: using --scan-open for protocol detection")
+		log.Println("first poll: using --scan-open for protocol detection, waking drives for SMART baseline")
 	}
 	dc.mu.Unlock()
 
@@ -676,7 +677,7 @@ func (dc *DriveCache) Refresh() {
 	var order []string
 
 	for _, dev := range scanResult.Devices {
-		info, inStandby := dc.fetchDriveInfo(dev.Name, dev.Protocol)
+		info, inStandby := dc.fetchDriveInfo(dev.Name, dev.Protocol, isFirstPoll)
 		if inStandby {
 			// Drive is sleeping -- serve last known data with standby flag.
 			slug := makeDriveSlug("", dev.Name) // fallback slug from path
@@ -779,7 +780,7 @@ func runSmartctl(smartctlPath string, args []string) ([]byte, int, error) {
 // fetchDriveInfo calls smartctl -a --json on a single device and parses the
 // key fields we care about. Returns (info, inStandby). When inStandby is true,
 // the drive was sleeping and no SMART data was collected.
-func (dc *DriveCache) fetchDriveInfo(devicePath, protocol string) (DriveInfo, bool) {
+func (dc *DriveCache) fetchDriveInfo(devicePath, protocol string, skipStandby bool) (DriveInfo, bool) {
 	// Check the protocol cache: if we have a confirmed working protocol for this
 	// device (e.g. "sat" from a previous SAT fallback, or a device_override),
 	// use it upfront instead of relying on the scan-reported protocol.
@@ -790,7 +791,7 @@ func (dc *DriveCache) fetchDriveInfo(devicePath, protocol string) (DriveInfo, bo
 	dc.mu.RUnlock()
 
 	args := []string{"--json", "-a"}
-	if dc.standbyMode != "never" {
+	if dc.standbyMode != "never" && !skipStandby {
 		args = append(args, "-n", dc.standbyMode)
 	}
 	if strings.EqualFold(protocol, "sat") {
@@ -814,7 +815,7 @@ func (dc *DriveCache) fetchDriveInfo(devicePath, protocol string) (DriveInfo, bo
 		// mismatch on NAS HBAs where SATA drives present as SCSI.
 		if code&0x07 != 0 && strings.EqualFold(protocol, "scsi") {
 			satArgs := []string{"--json", "-a", "-d", "sat"}
-			if dc.standbyMode != "never" {
+			if dc.standbyMode != "never" && !skipStandby {
 				satArgs = append(satArgs, "-n", dc.standbyMode)
 			}
 			satArgs = append(satArgs, devicePath)