api: added disabledCollectors config option

The validation of config options will be done by the operator's
validation webhook.
Validation tests are going to be part of the operator repo.
The MetricsExporterConfigSpec shall be inlined in
the StorageOSCluster.Spec.Metrics.
Operator will be responsible for ConfigMap's creation and patching based
on the StorageOSCluster.Spec.Metrics values.

Signed-off-by: Michal Minář <[email protected]>

api/config.storageos.com/v1/constants.go

@@ -0,0 +1,23 @@
+/*
+Copyright 2022 Ondat.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package v1
+
+const (
+	// MetricsExporterConfigFileName is a mandatory key in the data field of the
+	// ConfigMap/storage-metrics-exporter. The associated value must be a valid MetricsExporterConfig
+	// serialized as YAML.
+	MetricsExporterConfigFileName = "config.yaml"
+)

api/config.storageos.com/v1/default.go

@@ -0,0 +1,26 @@
+/*
+Copyright 2022 Ondat.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+package v1
+
+func (c *MetricsExporterConfig) Default() *MetricsExporterConfig {
+	if c.LogLevel == "" {
+		c.LogLevel = "info"
+	}
+	if c.Timeout == 0 {
+		c.Timeout = 10
+	}
+	return c
+}

api/config.storageos.com/v1/metricsexporterconfig_types.go

@@ -28,6 +28,12 @@ type MetricsExporterConfig struct {
 	metav1.TypeMeta   `json:",inline"`
 	metav1.ObjectMeta `json:"metadata,omitempty"`
 
+	MetricsExporterConfigSpec `json:",inline"`
+}
+
+// MetricsExporterConfigSpec represents the configuration options for the metrics-exporter. These fields shall
+// be inlined in the StorageOSCluster.Spec.Metrics.
+type MetricsExporterConfigSpec struct {
 	// Verbosity of log messages. Accepts go.uber.org/zap log levels.
 	// +kubebuilder:default:info
 	// +kubebuilder:validation:Enum=debug;info;warn;error;dpanic;panic;fatal
@@ -36,9 +42,22 @@ type MetricsExporterConfig struct {
 	// Timeout in seconds to serve metrics.
 	// +kubebuilder:default:10
 	// +kubebuilder:validation:Minimum=1
-	Timeout int `json:"timeout"`
+	Timeout int `json:"timeout,omitempty"`
+
+	// DisabledCollectors is a list of collectors that shall be disabled. By default, all are enabled.
+	DisabledCollectors []MetricsExporterCollector `json:"disabledCollectors,omitempty"`
 }
 
+// MetricsExporterCollector is the name of a metrics collector in the metrics-exporter.
+// +kubebuilder:validation:Enum=diskstats;filesystem
+type MetricsExporterCollector string
+
+// All known metrics-exporter collectors are listed here.
+const (
+	MetricsExporterCollectorDiskStats  MetricsExporterCollector = "diskstats"
+	MetricsExporterCollectorFileSystem MetricsExporterCollector = "filesystem"
+)
+
 func init() {
 	SchemeBuilder.Register(&MetricsExporterConfig{})
 }

collector.go

@@ -7,6 +7,8 @@ import (
 	"github.com/google/uuid"
 	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
+
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 )
 
 type Collector interface {
@@ -77,3 +79,33 @@ func execute(log *zap.SugaredLogger, c Collector, ch chan<- prometheus.Metric, o
 	}
 	ch <- prometheus.MustNewConstMetric(scrapeSuccessMetric.desc, scrapeSuccessMetric.valueType, success, c.Name())
 }
+
+func GetEnabledMetricsCollectors(
+	log *zap.SugaredLogger,
+	disabled []configondatv1.MetricsExporterCollector,
+) []Collector {
+	var metricsCollectors []Collector
+	for name, collectorFactory := range map[configondatv1.MetricsExporterCollector](func() Collector){
+		configondatv1.MetricsExporterCollectorDiskStats:  func() Collector { return NewDiskStatsCollector() },
+		configondatv1.MetricsExporterCollectorFileSystem: func() Collector { return NewFileSystemCollector() },
+	} {
+		if IsCollectorDisabled(disabled, name) {
+			log.Infof("disabling %s collector", name)
+			continue
+		}
+		metricsCollectors = append(metricsCollectors, collectorFactory())
+	}
+	return metricsCollectors
+}
+
+func IsCollectorDisabled(
+	disabled []configondatv1.MetricsExporterCollector,
+	collector configondatv1.MetricsExporterCollector,
+) bool {
+	for _, c := range disabled {
+		if c == collector {
+			return true
+		}
+	}
+	return false
+}

collector_test.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
+
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
+)
+
+func TestGetEnabledMetricsCollectors(t *testing.T) {
+	tests := []struct {
+		name            string
+		disable         []configondatv1.MetricsExporterCollector
+		expectedEnabled []string
+	}{
+		{
+			name:    "all enabled",
+			disable: nil,
+			expectedEnabled: []string{
+				"diskstats",
+				"filesystem",
+			},
+		},
+
+		{
+			name:    "disable filesystem",
+			disable: []configondatv1.MetricsExporterCollector{configondatv1.MetricsExporterCollectorFileSystem},
+			expectedEnabled: []string{
+				"diskstats",
+			},
+		},
+
+		{
+			name:    "disable diskstats",
+			disable: []configondatv1.MetricsExporterCollector{configondatv1.MetricsExporterCollectorDiskStats},
+			expectedEnabled: []string{
+				"filesystem",
+			},
+		},
+
+		{
+			name: "disable both",
+			disable: []configondatv1.MetricsExporterCollector{
+				configondatv1.MetricsExporterCollectorFileSystem,
+				configondatv1.MetricsExporterCollectorDiskStats,
+			},
+			expectedEnabled: []string{},
+		},
+
+		{
+			name: "disable both - reversed",
+			disable: []configondatv1.MetricsExporterCollector{
+				configondatv1.MetricsExporterCollectorDiskStats,
+				configondatv1.MetricsExporterCollectorFileSystem,
+			},
+			expectedEnabled: []string{},
+		},
+
+		{
+			name: "ignore bad value",
+			disable: []configondatv1.MetricsExporterCollector{
+				configondatv1.MetricsExporterCollector("bad"),
+				configondatv1.MetricsExporterCollectorFileSystem,
+			},
+			expectedEnabled: []string{
+				"diskstats",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		var tt = tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			loggerConfig := zap.NewProductionConfig()
+			logger, _ := loggerConfig.Build()
+			log := logger.Sugar()
+
+			collectors := GetEnabledMetricsCollectors(log, tt.disable)
+			names := make([]string, 0, len(collectors))
+			for _, c := range collectors {
+				names = append(names, c.Name())
+			}
+			require.ElementsMatch(t, tt.expectedEnabled, names)
+		})
+	}
+}

config.go

@@ -22,16 +22,10 @@ import (
 	"log"
 	"os"
 
-	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/serializer"
-)
 
-var (
-	configDefaults = configondatv1.MetricsExporterConfig{
-		LogLevel: "info",
-		Timeout:  10,
-	}
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 )
 
 func readConfigFile(path string) (*configondatv1.MetricsExporterConfig, error) {
@@ -42,25 +36,28 @@ func readConfigFile(path string) (*configondatv1.MetricsExporterConfig, error) {
 
 	codecs := serializer.NewCodecFactory(scheme)
 
-	cfg := *configDefaults.DeepCopy()
-	if err = runtime.DecodeInto(codecs.UniversalDecoder(), content, &cfg); err != nil {
+	cfg := (&configondatv1.MetricsExporterConfig{}).Default()
+	if err = runtime.DecodeInto(codecs.UniversalDecoder(), content, cfg); err != nil {
 		return nil, fmt.Errorf("could not decode file into runtime.Object: %v", err)
 	}
-	return &cfg, nil
+
+	return cfg, nil
 }
 
 func getConfigOrDie() (path string, cfg configondatv1.MetricsExporterConfig) {
 	var configFile string
 	var logLevelFlag string
 	var timeoutFlag int
 
+	defaults := (&configondatv1.MetricsExporterConfig{}).Default()
+
 	flag.StringVar(&configFile, "config", "",
 		"The exporter will load its initial configuration from this file. "+
 			"Omit this flag to use the default configuration values. "+
 			"Command-line flags override configuration from this file.")
-	flag.StringVar(&logLevelFlag, "log-level", configDefaults.LogLevel,
+	flag.StringVar(&logLevelFlag, "log-level", defaults.LogLevel,
 		"Verbosity of log messages. Accepts go.uber.org/zap log levels.")
-	flag.IntVar(&timeoutFlag, "timeout", configDefaults.Timeout, "Timeout in seconds to serve metrics.")
+	flag.IntVar(&timeoutFlag, "timeout", defaults.Timeout, "Timeout in seconds to serve metrics.")
 	flag.Parse()
 
 	if len(configFile) > 0 {
@@ -71,7 +68,7 @@ func getConfigOrDie() (path string, cfg configondatv1.MetricsExporterConfig) {
 		}
 		cfg = *parsedCfg
 	} else {
-		cfg = *configDefaults.DeepCopy()
+		cfg = *defaults
 	}
 
 	// override defaults/configmap with the supplied flag values

diskstats_collector.go

@@ -5,13 +5,15 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
+
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 )
 
 const (
 	// SECOND_IN_MILLISECONDS defines the number of seconds on a milliseconds. Used
 	// to transform metrics that express a duration in milliseconds.
 	SECOND_IN_MILLISECONDS   = 1.0 / 1000.0
-	DISKSTATS_COLLECTOR_NAME = "diskstats"
+	DISKSTATS_COLLECTOR_NAME = string(configondatv1.MetricsExporterCollectorDiskStats)
 )
 
 // DiskStatsCollector implements the prometheus Collector interface

filesystem_collector.go

@@ -13,9 +13,11 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
 	"golang.org/x/sys/unix"
+
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 )
 
-const FILE_SYSTEM_COLLECTOR_NAME = "filesystem"
+const FILE_SYSTEM_COLLECTOR_NAME = string(configondatv1.MetricsExporterCollectorFileSystem)
 
 var stuckMounts = make(map[string]struct{})
 var stuckMountsMtx = &sync.Mutex{}

main.go

@@ -23,13 +23,14 @@ import (
 	"os"
 	"time"
 
-	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+
+	configondatv1 "github.com/ondat/metrics-exporter/api/config.storageos.com/v1"
 )
 
 const (
@@ -72,9 +73,9 @@ func main() {
 	}
 	log.Debugf("Serve metrics timeout set to %d seconds", cfg.Timeout)
 
-	metricsCollectors := []Collector{
-		NewDiskStatsCollector(),
-		NewFileSystemCollector(),
+	metricsCollectors := GetEnabledMetricsCollectors(log, cfg.DisabledCollectors)
+	if len(metricsCollectors) == 0 {
+		log.Fatal("there is nothing to do with all metrics collectors disabled")
 	}
 
 	prometheusRegistry := prometheus.NewRegistry()