From 0764f8824ed0dcad7692e1b29d16b3932dc4f8b8 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Thu, 5 Apr 2018 22:12:25 +0200
Subject: [PATCH] zfs: prometheus metrics

refs #67
---
 zfs/prometheus.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++
 zfs/versions.go   | 11 ++++++++++
 zfs/zfs.go        |  7 +++++++
 3 files changed, 71 insertions(+)
 create mode 100644 zfs/prometheus.go

diff --git a/zfs/prometheus.go b/zfs/prometheus.go
new file mode 100644
index 0000000..f27d797
--- /dev/null
+++ b/zfs/prometheus.go
@@ -0,0 +1,53 @@
+package zfs
+
+import "github.com/prometheus/client_golang/prometheus"
+
+var prom struct {
+	ZFSListFilesystemVersionDuration    *prometheus.HistogramVec
+	ZFSDestroyFilesystemVersionDuration *prometheus.HistogramVec
+	ZFSSnapshotDuration                 *prometheus.HistogramVec
+	ZFSBookmarkDuration                 *prometheus.HistogramVec
+}
+
+func init() {
+	prom.ZFSListFilesystemVersionDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "zrepl",
+		Subsystem: "zfs",
+		Name:      "list_filesystem_versions_duration",
+		Help:      "Seconds it took for listing the versions of a given filesystem",
+	}, []string{"filesystem"})
+	prom.ZFSDestroyFilesystemVersionDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "zrepl",
+		Subsystem: "zfs",
+		Name:      "destroy_filesystem_version_duration",
+		Help:      "Seconds it took to destroy a version of a given filesystem",
+	}, []string{"filesystem", "version_type"})
+	prom.ZFSSnapshotDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "zrepl",
+		Subsystem: "zfs",
+		Name:      "snapshot_duration",
+		Help:      "Seconds it took to create a snapshot a given filesystem",
+	}, []string{"filesystem"})
+	prom.ZFSBookmarkDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "zrepl",
+		Subsystem: "zfs",
+		Name:      "bookmark_duration",
+		Help:      "Duration it took to bookmark a given snapshot",
+	}, []string{"filesystem"})
+}
+
+func PrometheusRegister(registry prometheus.Registerer) error {
+	if err := registry.Register(prom.ZFSListFilesystemVersionDuration); err != nil {
+		return err
+	}
+	if err := registry.Register(prom.ZFSDestroyFilesystemVersionDuration); err != nil {
+		return err
+	}
+	if err := registry.Register(prom.ZFSBookmarkDuration); err != nil {
+		return err
+	}
+	if err := registry.Register(prom.ZFSSnapshotDuration); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/zfs/versions.go b/zfs/versions.go
index 643c74a..1ef9e20 100644
--- a/zfs/versions.go
+++ b/zfs/versions.go
@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"github.com/prometheus/client_golang/prometheus"
 	"strconv"
 	"strings"
 	"time"
@@ -28,6 +29,10 @@ func (t VersionType) DelimiterChar() string {
 	}
 }
 
+func (t VersionType) String() string {
+	return string(t)
+}
+
 type FilesystemVersion struct {
 	Type VersionType
 
@@ -64,6 +69,9 @@ type FilesystemVersionFilter interface {
 func ZFSListFilesystemVersions(fs *DatasetPath, filter FilesystemVersionFilter) (res []FilesystemVersion, err error) {
 	listResults := make(chan ZFSListResult)
 
+	promTimer := prometheus.NewTimer(prom.ZFSListFilesystemVersionDuration.WithLabelValues(fs.ToString()))
+	defer promTimer.ObserveDuration()
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 	go ZFSListChan(ctx, listResults,
@@ -137,6 +145,9 @@ func ZFSListFilesystemVersions(fs *DatasetPath, filter FilesystemVersionFilter)
 
 func ZFSDestroyFilesystemVersion(filesystem *DatasetPath, version FilesystemVersion) (err error) {
 
+	promTimer := prometheus.NewTimer(prom.ZFSDestroyFilesystemVersionDuration.WithLabelValues(filesystem.ToString(), version.Type.String()))
+	defer promTimer.ObserveDuration()
+
 	datasetPath := version.ToAbsPath(filesystem)
 
 	// Sanity check...
diff --git a/zfs/zfs.go b/zfs/zfs.go
index f6a3b2b..29da261 100644
--- a/zfs/zfs.go
+++ b/zfs/zfs.go
@@ -12,6 +12,7 @@ import (
 
 	"context"
 	"github.com/problame/go-rwccmd"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/zrepl/zrepl/util"
 )
 
@@ -386,6 +387,9 @@ func zfsBuildBookmarkName(fs *DatasetPath, name string) string { // TODO defensi
 
 func ZFSSnapshot(fs *DatasetPath, name string, recursive bool) (err error) {
 
+	promTimer := prometheus.NewTimer(prom.ZFSSnapshotDuration.WithLabelValues(fs.ToString()))
+	defer promTimer.ObserveDuration()
+
 	snapname := zfsBuildSnapName(fs, name)
 	cmd := exec.Command(ZFS_BINARY, "snapshot", snapname)
 
@@ -409,6 +413,9 @@ func ZFSSnapshot(fs *DatasetPath, name string, recursive bool) (err error) {
 
 func ZFSBookmark(fs *DatasetPath, snapshot, bookmark string) (err error) {
 
+	promTimer := prometheus.NewTimer(prom.ZFSBookmarkDuration.WithLabelValues(fs.ToString()))
+	defer promTimer.ObserveDuration()
+
 	snapname := zfsBuildSnapName(fs, snapshot)
 	bookmarkname := zfsBuildBookmarkName(fs, bookmark)