zfs: move Linux-specific code out of zfs.go

Avoid Linux-specific code scattered in two places by moving it to the
already-existing zfs_linux.go.

Signed-off-by: Daniel Swarbrick <daniel.swarbrick@gmail.com>

collector/zfs.go

@@ -11,148 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build linux && !nozfs
+//go:build !nozfs
-// +build linux,!nozfs
+// +build !nozfs
 
 package collector
-
-import (
-	"errors"
-	"log/slog"
-	"strings"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-var errZFSNotAvailable = errors.New("ZFS / ZFS statistics are not available")
-
-type zfsSysctl string
-
-func init() {
-	registerCollector("zfs", defaultEnabled, NewZFSCollector)
-}
-
-type zfsCollector struct {
-	linuxProcpathBase    string
-	linuxZpoolIoPath     string
-	linuxZpoolObjsetPath string
-	linuxZpoolStatePath  string
-	linuxPathMap         map[string]string
-	logger               *slog.Logger
-}
-
-// NewZFSCollector returns a new Collector exposing ZFS statistics.
-func NewZFSCollector(logger *slog.Logger) (Collector, error) {
-	return &zfsCollector{
-		linuxProcpathBase:    "spl/kstat/zfs",
-		linuxZpoolIoPath:     "/*/io",
-		linuxZpoolObjsetPath: "/*/objset-*",
-		linuxZpoolStatePath:  "/*/state",
-		linuxPathMap: map[string]string{
-			"zfs_abd":         "abdstats",
-			"zfs_arc":         "arcstats",
-			"zfs_dbuf":        "dbufstats",
-			"zfs_dmu_tx":      "dmu_tx",
-			"zfs_dnode":       "dnodestats",
-			"zfs_fm":          "fm",
-			"zfs_vdev_cache":  "vdev_cache_stats", // vdev_cache is deprecated
-			"zfs_vdev_mirror": "vdev_mirror_stats",
-			"zfs_xuio":        "xuio_stats", // no known consumers of the XUIO interface on Linux exist
-			"zfs_zfetch":      "zfetchstats",
-			"zfs_zil":         "zil",
-		},
-		logger: logger,
-	}, nil
-}
-
-func (c *zfsCollector) Update(ch chan<- prometheus.Metric) error {
-
-	if _, err := c.openProcFile(c.linuxProcpathBase); err != nil {
-		if err == errZFSNotAvailable {
-			c.logger.Debug(err.Error())
-			return ErrNoData
-		}
-	}
-
-	for subsystem := range c.linuxPathMap {
-		if err := c.updateZfsStats(subsystem, ch); err != nil {
-			if err == errZFSNotAvailable {
-				c.logger.Debug(err.Error())
-				// ZFS /proc files are added as new features to ZFS arrive, it is ok to continue
-				continue
-			}
-			return err
-		}
-	}
-
-	// Pool stats
-	return c.updatePoolStats(ch)
-}
-
-func (s zfsSysctl) metricName() string {
-	parts := strings.Split(string(s), ".")
-	return strings.Replace(parts[len(parts)-1], "-", "_", -1)
-}
-
-func (c *zfsCollector) constSysctlMetric(subsystem string, sysctl zfsSysctl, value float64) prometheus.Metric {
-	metricName := sysctl.metricName()
-
-	return prometheus.MustNewConstMetric(
-		prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, subsystem, metricName),
-			string(sysctl),
-			nil,
-			nil,
-		),
-		prometheus.UntypedValue,
-		value,
-	)
-}
-
-func (c *zfsCollector) constPoolMetric(poolName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
-	metricName := sysctl.metricName()
-
-	return prometheus.MustNewConstMetric(
-		prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "zfs_zpool", metricName),
-			string(sysctl),
-			[]string{"zpool"},
-			nil,
-		),
-		prometheus.UntypedValue,
-		float64(value),
-		poolName,
-	)
-}
-
-func (c *zfsCollector) constPoolObjsetMetric(poolName string, datasetName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
-	metricName := sysctl.metricName()
-
-	return prometheus.MustNewConstMetric(
-		prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "zfs_zpool_dataset", metricName),
-			string(sysctl),
-			[]string{"zpool", "dataset"},
-			nil,
-		),
-		prometheus.UntypedValue,
-		float64(value),
-		poolName,
-		datasetName,
-	)
-}
-
-func (c *zfsCollector) constPoolStateMetric(poolName string, stateName string, isActive uint64) prometheus.Metric {
-	return prometheus.MustNewConstMetric(
-		prometheus.NewDesc(
-			prometheus.BuildFQName(namespace, "zfs_zpool", "state"),
-			"kstat.zfs.misc.state",
-			[]string{"zpool", "state"},
-			nil,
-		),
-		prometheus.GaugeValue,
-		float64(isActive),
-		poolName,
-		stateName,
-	)
-}

collector/zfs_linux.go

@@ -18,8 +18,10 @@ package collector
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -41,7 +43,71 @@ const (
 	// kstatDataString = "7"
 )
 
-var zfsPoolStatesName = []string{"online", "degraded", "faulted", "offline", "removed", "unavail", "suspended"}
+var (
+	errZFSNotAvailable = errors.New("ZFS / ZFS statistics are not available")
+
+	zfsPoolStatesName = []string{"online", "degraded", "faulted", "offline", "removed", "unavail", "suspended"}
+)
+
+type zfsCollector struct {
+	linuxProcpathBase    string
+	linuxZpoolIoPath     string
+	linuxZpoolObjsetPath string
+	linuxZpoolStatePath  string
+	linuxPathMap         map[string]string
+	logger               *slog.Logger
+}
+
+func init() {
+	registerCollector("zfs", defaultEnabled, NewZFSCollector)
+}
+
+// NewZFSCollector returns a new Collector exposing ZFS statistics.
+func NewZFSCollector(logger *slog.Logger) (Collector, error) {
+	return &zfsCollector{
+		linuxProcpathBase:    "spl/kstat/zfs",
+		linuxZpoolIoPath:     "/*/io",
+		linuxZpoolObjsetPath: "/*/objset-*",
+		linuxZpoolStatePath:  "/*/state",
+		linuxPathMap: map[string]string{
+			"zfs_abd":         "abdstats",
+			"zfs_arc":         "arcstats",
+			"zfs_dbuf":        "dbufstats",
+			"zfs_dmu_tx":      "dmu_tx",
+			"zfs_dnode":       "dnodestats",
+			"zfs_fm":          "fm",
+			"zfs_vdev_cache":  "vdev_cache_stats", // vdev_cache is deprecated
+			"zfs_vdev_mirror": "vdev_mirror_stats",
+			"zfs_xuio":        "xuio_stats", // no known consumers of the XUIO interface on Linux exist
+			"zfs_zfetch":      "zfetchstats",
+			"zfs_zil":         "zil",
+		},
+		logger: logger,
+	}, nil
+}
+
+func (c *zfsCollector) Update(ch chan<- prometheus.Metric) error {
+	if _, err := c.openProcFile(c.linuxProcpathBase); err != nil {
+		if err == errZFSNotAvailable {
+			c.logger.Debug(err.Error())
+			return ErrNoData
+		}
+	}
+
+	for subsystem := range c.linuxPathMap {
+		if err := c.updateZfsStats(subsystem, ch); err != nil {
+			if err == errZFSNotAvailable {
+				c.logger.Debug(err.Error())
+				// ZFS /proc files are added as new features to ZFS arrive, it is ok to continue
+				continue
+			}
+			return err
+		}
+	}
+
+	// Pool stats
+	return c.updatePoolStats(ch)
+}
 
 func (c *zfsCollector) openProcFile(path string) (*os.File, error) {
 	file, err := os.Open(procFilePath(path))
@@ -304,3 +370,73 @@ func (c *zfsCollector) parsePoolStateFile(reader io.Reader, zpoolPath string, ha
 
 	return nil
 }
+
+func (c *zfsCollector) constSysctlMetric(subsystem string, sysctl zfsSysctl, value float64) prometheus.Metric {
+	metricName := sysctl.metricName()
+
+	return prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, subsystem, metricName),
+			string(sysctl),
+			nil,
+			nil,
+		),
+		prometheus.UntypedValue,
+		value,
+	)
+}
+
+func (c *zfsCollector) constPoolMetric(poolName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
+	metricName := sysctl.metricName()
+
+	return prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "zfs_zpool", metricName),
+			string(sysctl),
+			[]string{"zpool"},
+			nil,
+		),
+		prometheus.UntypedValue,
+		float64(value),
+		poolName,
+	)
+}
+
+func (c *zfsCollector) constPoolObjsetMetric(poolName string, datasetName string, sysctl zfsSysctl, value uint64) prometheus.Metric {
+	metricName := sysctl.metricName()
+
+	return prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "zfs_zpool_dataset", metricName),
+			string(sysctl),
+			[]string{"zpool", "dataset"},
+			nil,
+		),
+		prometheus.UntypedValue,
+		float64(value),
+		poolName,
+		datasetName,
+	)
+}
+
+func (c *zfsCollector) constPoolStateMetric(poolName string, stateName string, isActive uint64) prometheus.Metric {
+	return prometheus.MustNewConstMetric(
+		prometheus.NewDesc(
+			prometheus.BuildFQName(namespace, "zfs_zpool", "state"),
+			"kstat.zfs.misc.state",
+			[]string{"zpool", "state"},
+			nil,
+		),
+		prometheus.GaugeValue,
+		float64(isActive),
+		poolName,
+		stateName,
+	)
+}
+
+type zfsSysctl string
+
+func (s zfsSysctl) metricName() string {
+	parts := strings.Split(string(s), ".")
+	return strings.Replace(parts[len(parts)-1], "-", "_", -1)
+}