From 7ae07d544790485996674a983996147078090570 Mon Sep 17 00:00:00 2001
From: Bill Thiede <git@xinu.tv>
Date: Sun, 15 Jan 2023 11:04:52 -0800
Subject: [PATCH] Add support for linux snapshot naming pattern.

---
 zfs_replication_exporter.go | 47 ++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 9 deletions(-)

diff --git a/zfs_replication_exporter.go b/zfs_replication_exporter.go
index 528b23f..4c57075 100644
--- a/zfs_replication_exporter.go
+++ b/zfs_replication_exporter.go
@@ -32,9 +32,21 @@ var (
 const snapshotListCmd = "/sbin/zfs list -t snapshot -H -o name -s name"
 
 var (
-	// Example: @auto-20171001.1400-2w
-	snapshotPattern = regexp.MustCompile(`^[^@]+@auto-(\d{8}\.\d{4})-\d+[mwy]$`)
-	snapshotFormat  = "20060102.1504"
+	// FreeNAS example:
+	//   @auto-20171001.1400-2w
+	freenasSnapshotPattern = regexp.MustCompile(`^[^@]+@auto-(\d{8}\.\d{4})-\d+[mwy]$`)
+	// Linux examples:
+	//   @zfs-auto-snap_frequent-2023-01-15-18h00U
+	//   @zfs-auto-snap_frequent-2023-01-15-18h15U
+	//   @zfs-auto-snap_frequent-2023-01-15-18h30U
+	//   @zfs-auto-snap_frequent-2023-01-15-18h45U
+	//   @zfs-auto-snap_daily-2023-01-14-08h00U
+	//   @zfs-auto-snap_hourly-2023-01-14-19h00U
+	//   @zfs-auto-snap_weekly-2022-12-19-08h00U
+	//   @zfs-auto-snap_monthly-2022-12-01-08h00U
+	linuxSnapshotPattern  = regexp.MustCompile(`^[^@]+@zfs-auto-snap_(?:frequent|daily|hourly|weekly|monthly)-(\d{4}-\d{2}-\d{2}-\d{2}h\d{2}U)$`)
+	freenasSnapshotFormat = "20060102.1504"
+	linuxSnapshotFormat   = "2006-01-02-15h04U"
 
 	fetchRequestDurationMetric = prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "ssh_fetch_duration_seconds",
@@ -130,8 +142,6 @@ func fetchSnapshotStats(host string, c *ssh.Client) (snapshotStats, error) {
 	stats := snapshotStats(make(map[filesystemName]*filesystemStat))
 	for scanner.Scan() {
 		l := scanner.Text()
-		m := snapshotPattern.FindStringSubmatch(l)
-
 		filesystem := l
 		if idx := strings.Index(l, "@"); idx != -1 {
 			filesystem = l[:idx]
@@ -141,10 +151,13 @@ func fetchSnapshotStats(host string, c *ssh.Client) (snapshotStats, error) {
 			stats[name] = &filesystemStat{}
 		}
 		stats[name].Counts++
-		if len(m) == 2 {
-			t, err := time.Parse(snapshotFormat, m[1])
+
+		var foundSnapshot bool
+		if m := freenasSnapshotPattern.FindStringSubmatch(l); len(m) == 2 {
+			foundSnapshot = true
+			t, err := time.Parse(freenasSnapshotFormat, m[1])
 			if err != nil {
-				glog.Errorf("[%s] Malformed time in snapshot %q: %v", host, m[1], err)
+				glog.Errorf("[%s] Malformed time in freenas snapshot %q: %v", host, m[1], err)
 				continue
 			}
 			glog.V(3).Infof("filesystem: %s timestamp %v", l, t)
@@ -154,7 +167,23 @@ func fetchSnapshotStats(host string, c *ssh.Client) (snapshotStats, error) {
 			if snapshotTime.Before(t) {
 				stats[name].Timestamp = t
 			}
-		} else {
+		}
+		if m := linuxSnapshotPattern.FindStringSubmatch(l); len(m) == 2 {
+			foundSnapshot = true
+			t, err := time.Parse(linuxSnapshotFormat, m[1])
+			if err != nil {
+				glog.Errorf("[%s] Malformed time in linux snapshot %q: %v", host, m[1], err)
+				continue
+			}
+			glog.V(3).Infof("filesystem: %s timestamp %v", l, t)
+			stats[name].FreenasCounts++
+			snapshotTime := stats[name].Timestamp
+			glog.V(3).Infof("snapshotTime.Before(t) = %v snapshotTime: %v t: %v", snapshotTime.Before(t), snapshotTime, t)
+			if snapshotTime.Before(t) {
+				stats[name].Timestamp = t
+			}
+		}
+		if !foundSnapshot {
 			glog.V(3).Infof("[%s] Skipping snapshot with non-conforming timestamp %q", host, l)
 		}
 	}