Refactor metrics package to implement reader interface

internal/http/services/prometheus/prometheus.go

@@ -21,14 +21,15 @@ package prometheus
 import (
 	"net/http"
 
-	"github.com/cs3org/reva/pkg/metrics"
-
 	"contrib.go.opencensus.io/exporter/prometheus"
 	"github.com/cs3org/reva/pkg/rhttp/global"
 	"github.com/mitchellh/mapstructure"
 	"github.com/pkg/errors"
 	"github.com/rs/zerolog"
 	"go.opencensus.io/stats/view"
+
+	// Initializes goroutines which periodically update stats
+	_ "github.com/cs3org/reva/pkg/metrics/reader/dummy"
 )
 
 func init() {
@@ -52,16 +53,6 @@ func New(m map[string]interface{}, log *zerolog.Logger) (global.Service, error)
 	}
 
 	view.RegisterExporter(pe)
-
-	// register the desired measures' views
-	if err = view.Register(
-		metrics.GetNumUsersView(),
-		metrics.GetNumGroupsView(),
-		metrics.GetAmountStorageView(),
-	); err != nil {
-		return nil, errors.Wrap(err, "prometheus: error registering exporter")
-	}
-
 	return &svc{prefix: conf.Prefix, h: pe}, nil
 }
 

pkg/metrics/metrics.go

@@ -18,96 +18,22 @@
 
 package metrics
 
-// This package defines site metrics measures and views based on opencensus.io
-
 import (
-	"context"
-	"math/rand"
-	"time"
-
-	"go.opencensus.io/stats"
 	"go.opencensus.io/stats/view"
 )
 
-func init() {
-	// call the actual metric provider functions for the latest metrics every 4th second
-	go func() {
-		rand.Seed(time.Now().UnixNano())
-		for {
-			getNumUsers()
-			getNumGroups()
-			getAmountStorage()
-			time.Sleep(4 * time.Second)
-		}
-	}()
-}
-
-// Create the measures
-var (
-	NumUsersMeasure      = stats.Int64("cs3_org_sciencemesh_site_total_num_users", "The total number of users within this site", stats.UnitDimensionless)
-	NumGroupsMeasure     = stats.Int64("cs3_org_sciencemesh_site_total_num_groups", "The total number of groups within this site", stats.UnitDimensionless)
-	AmountStorageMeasure = stats.Int64("cs3_org_sciencemesh_site_total_amount_storage", "The total amount of storage used within this site", stats.UnitBytes)
-)
-
-// initialize local dummy counters
-var (
-	numUsersCounter      = int64(0)
-	amountStorageCounter = int64(0)
-)
+// Reader is the interface that defines how the metrics will be read.
+type Reader interface {
 
-// getNumberUsers links to the underlying number of site users provider
-func getNumUsers() {
-	ctx := context.Background()
-	// here we must request the actual number of site users
-	// for now this is a mockup: a number increasing over time
-	numUsersCounter += int64(rand.Intn(100))
-	stats.Record(ctx, NumUsersMeasure.M(numUsersCounter))
-}
+	// GetNumUsersView returns an OpenCensus stats view which records the
+	// number of users registered in the mesh provider.
+	GetNumUsersView() *view.View
 
-// GetNumUsersView returns the number of site users measure view
-func GetNumUsersView() *view.View {
-	return &view.View{
-		Name:        NumUsersMeasure.Name(),
-		Description: NumUsersMeasure.Description(),
-		Measure:     NumUsersMeasure,
-		Aggregation: view.LastValue(),
-	}
-}
-
-// getNumberGroups links to the underlying number of site groups provider
-func getNumGroups() {
-	ctx := context.Background()
-	// here we must request the actual number of site groups
-	// for now this is a mockup: a number changing over time
-	var numGroupsCounter = int64(rand.Intn(100))
-	stats.Record(ctx, NumGroupsMeasure.M(numGroupsCounter))
-}
-
-// GetNumGroupsView returns the number of site groups measure view
-func GetNumGroupsView() *view.View {
-	return &view.View{
-		Name:        NumGroupsMeasure.Name(),
-		Description: NumGroupsMeasure.Description(),
-		Measure:     NumGroupsMeasure,
-		Aggregation: view.LastValue(),
-	}
-}
-
-// getAmountStorage links to the underlying amount of storage provider
-func getAmountStorage() {
-	ctx := context.Background()
-	// here we must request the actual amount of storage used
-	// for now this is a mockup: a number increasing over time
-	amountStorageCounter += int64(rand.Intn(12865000))
-	stats.Record(ctx, AmountStorageMeasure.M(amountStorageCounter))
-}
+	// GetNumGroupsView returns an OpenCensus stats view which records the
+	// number of user groups registered in the mesh provider.
+	GetNumGroupsView() *view.View
 
-// GetAmountStorageView returns the amount of site storage measure view
-func GetAmountStorageView() *view.View {
-	return &view.View{
-		Name:        AmountStorageMeasure.Name(),
-		Description: AmountStorageMeasure.Description(),
-		Measure:     AmountStorageMeasure,
-		Aggregation: view.LastValue(),
-	}
+	// GetAmountStorageView returns an OpenCensus stats view which records the
+	// amount of storage in the system.
+	GetAmountStorageView() *view.View
 }

pkg/metrics/reader/dummy/dummy.go

@@ -0,0 +1,131 @@
+// Copyright 2018-2020 CERN
+//
+// 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.
+//
+// In applying this license, CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+package dummy
+
+import (
+	"context"
+	"math/rand"
+	"os"
+	"time"
+
+	"github.com/cs3org/reva/pkg/logger"
+	"github.com/cs3org/reva/pkg/metrics"
+	"go.opencensus.io/stats"
+	"go.opencensus.io/stats/view"
+)
+
+func init() {
+
+	log := logger.New().With().Int("pid", os.Getpid()).Logger()
+
+	m := &Metrics{
+		NumUsersMeasure:      stats.Int64("cs3_org_sciencemesh_site_total_num_users", "The total number of users within this site", stats.UnitDimensionless),
+		NumGroupsMeasure:     stats.Int64("cs3_org_sciencemesh_site_total_num_groups", "The total number of groups within this site", stats.UnitDimensionless),
+		AmountStorageMeasure: stats.Int64("cs3_org_sciencemesh_site_total_amount_storage", "The total amount of storage used within this site", stats.UnitBytes),
+	}
+
+	// Verify that the struct implements the metrics.Reader interface
+	_, ok := interface{}(m).(metrics.Reader)
+	if !ok {
+		log.Error().Msg("the driver does not implement the metrics.Reader interface")
+		return
+	}
+
+	// register the desired measures' views
+	if err := view.Register(
+		m.GetNumUsersView(),
+		m.GetNumGroupsView(),
+		m.GetAmountStorageView(),
+	); err != nil {
+		log.Error().Err(err).Msg("error registering views with opencensus exporter")
+		return
+	}
+
+	// call the actual metric provider functions for the latest metrics every 4th second
+	go func() {
+		rand.Seed(time.Now().UnixNano())
+		for {
+			m.getNumUsers()
+			m.getNumGroups()
+			m.getAmountStorage()
+			time.Sleep(4 * time.Second)
+		}
+	}()
+}
+
+// Metrics returns randomly generated values for the defined metrics.
+type Metrics struct {
+	numUsersCounter      int64
+	amountStorageCounter int64
+
+	NumUsersMeasure      *stats.Int64Measure
+	NumGroupsMeasure     *stats.Int64Measure
+	AmountStorageMeasure *stats.Int64Measure
+}
+
+// getNumberUsers links to the underlying number of site users provider
+func (m *Metrics) getNumUsers() {
+	ctx := context.Background()
+	m.numUsersCounter += int64(rand.Intn(100))
+	stats.Record(ctx, m.NumUsersMeasure.M(m.numUsersCounter))
+}
+
+// GetNumUsersView returns the number of site users measure view
+func (m *Metrics) GetNumUsersView() *view.View {
+	return &view.View{
+		Name:        m.NumUsersMeasure.Name(),
+		Description: m.NumUsersMeasure.Description(),
+		Measure:     m.NumUsersMeasure,
+		Aggregation: view.LastValue(),
+	}
+}
+
+// getNumberGroups links to the underlying number of site groups provider
+func (m *Metrics) getNumGroups() {
+	ctx := context.Background()
+	var numGroupsCounter = int64(rand.Intn(100))
+	stats.Record(ctx, m.NumGroupsMeasure.M(numGroupsCounter))
+}
+
+// GetNumGroupsView returns the number of site groups measure view
+func (m *Metrics) GetNumGroupsView() *view.View {
+	return &view.View{
+		Name:        m.NumGroupsMeasure.Name(),
+		Description: m.NumGroupsMeasure.Description(),
+		Measure:     m.NumGroupsMeasure,
+		Aggregation: view.LastValue(),
+	}
+}
+
+// getAmountStorage links to the underlying amount of storage provider
+func (m *Metrics) getAmountStorage() {
+	ctx := context.Background()
+	m.amountStorageCounter += int64(rand.Intn(12865000))
+	stats.Record(ctx, m.AmountStorageMeasure.M(m.amountStorageCounter))
+}
+
+// GetAmountStorageView returns the amount of site storage measure view
+func (m *Metrics) GetAmountStorageView() *view.View {
+	return &view.View{
+		Name:        m.AmountStorageMeasure.Name(),
+		Description: m.AmountStorageMeasure.Description(),
+		Measure:     m.AmountStorageMeasure,
+		Aggregation: view.LastValue(),
+	}
+}

pkg/metrics/reader/script/script.go

@@ -0,0 +1,78 @@
+// Copyright 2018-2020 CERN
+//
+// 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.
+//
+// In applying this license, CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+package script
+
+import (
+	"os"
+
+	"github.com/cs3org/reva/pkg/logger"
+	"github.com/cs3org/reva/pkg/metrics"
+	"go.opencensus.io/stats"
+	"go.opencensus.io/stats/view"
+)
+
+func init() {
+
+	log := logger.New().With().Int("pid", os.Getpid()).Logger()
+
+	m := &Metrics{
+		NumUsersMeasure:      stats.Int64("cs3_org_sciencemesh_site_total_num_users", "The total number of users within this site", stats.UnitDimensionless),
+		NumGroupsMeasure:     stats.Int64("cs3_org_sciencemesh_site_total_num_groups", "The total number of groups within this site", stats.UnitDimensionless),
+		AmountStorageMeasure: stats.Int64("cs3_org_sciencemesh_site_total_amount_storage", "The total amount of storage used within this site", stats.UnitBytes),
+	}
+
+	// Verify that the struct implements the metrics.Reader interface
+	_, ok := interface{}(m).(metrics.Reader)
+	if !ok {
+		log.Error().Msg("the driver does not implement the metrics.Reader interface")
+		return
+	}
+
+	// register the desired measures' views
+	if err := view.Register(
+		m.GetNumUsersView(),
+		m.GetNumGroupsView(),
+		m.GetAmountStorageView(),
+	); err != nil {
+		log.Error().Err(err).Msg("error registering views with opencensus exporter")
+		return
+	}
+}
+
+// Metrics returns randomly generated values for the defined metrics.
+type Metrics struct {
+	NumUsersMeasure      *stats.Int64Measure
+	NumGroupsMeasure     *stats.Int64Measure
+	AmountStorageMeasure *stats.Int64Measure
+}
+
+// GetNumUsersView returns the number of site users measure view
+func (m *Metrics) GetNumUsersView() *view.View {
+	return nil
+}
+
+// GetNumGroupsView returns the number of site groups measure view
+func (m *Metrics) GetNumGroupsView() *view.View {
+	return nil
+}
+
+// GetAmountStorageView returns the amount of site storage measure view
+func (m *Metrics) GetAmountStorageView() *view.View {
+	return nil
+}