refactor(zfs): Allow testing collector output

TODO: Test caching

.github/workflows/release.yml

@@ -19,6 +19,9 @@ jobs:
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
+      - name: Go Report Card
+        uses: creekorful/[email protected]
+
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
       - name: Checkout
         id: checkout

README.md

@@ -1,6 +1,8 @@
 # ZFS Exporter
 
+[![Test](https://github.com/pdf/zfs_exporter/actions/workflows/test.yml/badge.svg)](https://github.com/pdf/zfs_exporter/actions/workflows/test.yml)
 [![Release](https://github.com/pdf/zfs_exporter/actions/workflows/release.yml/badge.svg)](https://github.com/pdf/zfs_exporter/actions/workflows/release.yml)
+[![Go Report Card](https://goreportcard.com/badge/github.com/pdf/zfs_exporter)](https://goreportcard.com/report/github.com/pdf/zfs_exporter)
 [![License](https://img.shields.io/badge/License-MIT-%23a31f34)](https://github.com/pdf/zfs_exporter/blob/master/LICENSE)
 
 Prometheus exporter for ZFS (pools, filesystems, snapshots and volumes). Other implementations exist, however performance can be quite variable, producing occasional timeouts (and associated alerts). This exporter was built with a few features aimed at allowing users to avoid collecting more than they need to, and to ensure timeouts cannot occur, but that we eventually return useful data:

collector/collector.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/go-kit/log"
+	"github.com/pdf/zfs_exporter/zfs"
 	"github.com/prometheus/client_golang/prometheus"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
@@ -45,7 +46,7 @@ var (
 	errUnsupportedProperty = errors.New(`unsupported property`)
 )
 
-type factoryFunc func(l log.Logger, properties []string) (Collector, error)
+type factoryFunc func(l log.Logger, c zfs.Client, properties []string) (Collector, error)
 
 type transformFunc func(string) (float64, error)
 
@@ -60,6 +61,7 @@ type State struct {
 // Collector defines the minimum functionality for registering a collector
 type Collector interface {
 	update(ch chan<- metric, pools []string, excludes regexpCollection) error
+	describe(ch chan<- *prometheus.Desc)
 }
 
 type metric struct {

collector/collector_test.go

@@ -0,0 +1,52 @@
+package collector
+
+import (
+	"bytes"
+	"context"
+	"time"
+
+	"github.com/go-kit/kit/log"
+	"github.com/pdf/zfs_exporter/zfs"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+)
+
+var (
+	logger = log.NewNopLogger()
+	//logger = log.NewLogfmtLogger(os.Stderr)
+)
+
+func callCollector(ctx context.Context, collector prometheus.Collector, metricResults []byte, metricNames []string) error {
+	result := make(chan error)
+	go func() {
+		result <- testutil.CollectAndCompare(collector, bytes.NewBuffer(metricResults), metricNames...)
+	}()
+
+	select {
+	case err := <-result:
+		return err
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
+func defaultConfig(z zfs.Client) (ZFSConfig, error) {
+	duration, err := time.ParseDuration(`5m`)
+	if err != nil {
+		return ZFSConfig{}, err
+	}
+	return ZFSConfig{
+		DisableMetrics: true,
+		Deadline:       duration,
+		Logger:         logger,
+		ZFSClient:      z,
+	}, nil
+}
+
+func stringPointer(s string) *string {
+	return &s
+}
+
+func boolPointer(b bool) *bool {
+	return &b
+}

collector/dataset.go

@@ -7,6 +7,7 @@ import (
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 	"github.com/pdf/zfs_exporter/zfs"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 const (
@@ -165,9 +166,21 @@ func init() {
 }
 
 type datasetCollector struct {
-	kind  zfs.DatasetKind
-	log   log.Logger
-	props []string
+	kind   zfs.DatasetKind
+	log    log.Logger
+	client zfs.Client
+	props  []string
+}
+
+func (c *datasetCollector) describe(ch chan<- *prometheus.Desc) {
+	for _, k := range c.props {
+		prop, err := datasetProperties.find(k)
+		if err != nil {
+			_ = level.Warn(c.log).Log(`msg`, propertyUnsupportedMsg, `help`, helpIssue, `collector`, c.kind, `property`, k, `err`, err)
+			continue
+		}
+		ch <- prop.desc
+	}
 }
 
 func (c *datasetCollector) update(ch chan<- metric, pools []string, excludes regexpCollection) error {
@@ -193,13 +206,14 @@ func (c *datasetCollector) update(ch chan<- metric, pools []string, excludes reg
 }
 
 func (c *datasetCollector) updatePoolMetrics(ch chan<- metric, pool string, excludes regexpCollection) error {
-	datasets, err := zfs.DatasetProperties(pool, c.kind, c.props...)
+	datasets := c.client.Datasets(pool, c.kind)
+	props, err := datasets.Properties(c.props...)
 	if err != nil {
 		return err
 	}
 
-	for _, dataset := range datasets {
-		if excludes.MatchString(dataset.Name) {
+	for _, dataset := range props {
+		if excludes.MatchString(dataset.DatasetName()) {
 			continue
 		}
 		if err = c.updateDatasetMetrics(ch, pool, dataset); err != nil {
@@ -210,10 +224,10 @@ func (c *datasetCollector) updatePoolMetrics(ch chan<- metric, pool string, excl
 	return nil
 }
 
-func (c *datasetCollector) updateDatasetMetrics(ch chan<- metric, pool string, dataset zfs.Dataset) error {
-	labelValues := []string{dataset.Name, pool, string(c.kind)}
+func (c *datasetCollector) updateDatasetMetrics(ch chan<- metric, pool string, dataset zfs.DatasetProperties) error {
+	labelValues := []string{dataset.DatasetName(), pool, string(c.kind)}
 
-	for k, v := range dataset.Properties {
+	for k, v := range dataset.Properties() {
 		prop, err := datasetProperties.find(k)
 		if err != nil {
 			_ = level.Warn(c.log).Log(`msg`, propertyUnsupportedMsg, `help`, helpIssue, `collector`, c.kind, `property`, k, `err`, err)
@@ -226,24 +240,24 @@ func (c *datasetCollector) updateDatasetMetrics(ch chan<- metric, pool string, d
 	return nil
 }
 
-func newDatasetCollector(kind zfs.DatasetKind, l log.Logger, props []string) (Collector, error) {
+func newDatasetCollector(kind zfs.DatasetKind, l log.Logger, c zfs.Client, props []string) (Collector, error) {
 	switch kind {
 	case zfs.DatasetFilesystem, zfs.DatasetSnapshot, zfs.DatasetVolume:
 	default:
 		return nil, fmt.Errorf("unknown dataset type: %s", kind)
 	}
 
-	return &datasetCollector{kind: kind, log: l, props: props}, nil
+	return &datasetCollector{kind: kind, log: l, client: c, props: props}, nil
 }
 
-func newFilesystemCollector(l log.Logger, props []string) (Collector, error) {
-	return newDatasetCollector(zfs.DatasetFilesystem, l, props)
+func newFilesystemCollector(l log.Logger, c zfs.Client, props []string) (Collector, error) {
+	return newDatasetCollector(zfs.DatasetFilesystem, l, c, props)
 }
 
-func newSnapshotCollector(l log.Logger, props []string) (Collector, error) {
-	return newDatasetCollector(zfs.DatasetSnapshot, l, props)
+func newSnapshotCollector(l log.Logger, c zfs.Client, props []string) (Collector, error) {
+	return newDatasetCollector(zfs.DatasetSnapshot, l, c, props)
 }
 
-func newVolumeCollector(l log.Logger, props []string) (Collector, error) {
-	return newDatasetCollector(zfs.DatasetVolume, l, props)
+func newVolumeCollector(l log.Logger, c zfs.Client, props []string) (Collector, error) {
+	return newDatasetCollector(zfs.DatasetVolume, l, c, props)
 }