Implement VMMetrics factory and config V2

Github issue: open-telemetry#35

Testing done: make && make otelsvc

cmd/otelsvc/main.go

@@ -16,7 +16,10 @@
 // and traces and exports to a configured backend.
 package main
 
-import "github.com/open-telemetry/opentelemetry-service/otelsvc"
+import (
+	"github.com/open-telemetry/opentelemetry-service/otelsvc"
+	_ "github.com/open-telemetry/opentelemetry-service/receiver/vmmetricsreceiver"
+)
 
 func main() {
 	otelsvc.Run()

receiver/vmmetricsreceiver/config.go

@@ -0,0 +1,30 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// 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 vmmetricsreceiver
+
+import (
+	"time"
+
+	"github.com/open-telemetry/opentelemetry-service/models"
+)
+
+// ConfigV2 defines configuration for Prometheus receiver.
+type ConfigV2 struct {
+	models.ReceiverSettings `mapstructure:",squash"`
+	ScrapeInterval          time.Duration `mapstructure:"scrape_interval"`
+	MountPoint              string        `mapstructure:"mount_point"`
+	ProcessMountPoint       string        `mapstructure:"process_mount_point"`
+	MetricPrefix            string        `mapstructure:"metric_prefix"`
+}

receiver/vmmetricsreceiver/config_test.go

@@ -0,0 +1,57 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// 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 vmmetricsreceiver
+
+import (
+	"path"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/open-telemetry/opentelemetry-service/configv2"
+	"github.com/open-telemetry/opentelemetry-service/models"
+	"github.com/open-telemetry/opentelemetry-service/receiver"
+)
+
+var _ = configv2.RegisterTestFactories()
+
+func TestLoadConfig(t *testing.T) {
+	factory := receiver.GetReceiverFactory(typeStr)
+
+	config, err := configv2.LoadConfigFile(t, path.Join(".", "testdata", "config.yaml"))
+
+	require.NoError(t, err)
+	require.NotNil(t, config)
+
+	assert.Equal(t, len(config.Receivers), 2)
+
+	r0 := config.Receivers["vmmetrics"]
+	assert.Equal(t, r0, factory.CreateDefaultConfig())
+
+	r1 := config.Receivers["vmmetrics/customname"].(*ConfigV2)
+	assert.Equal(t, r1,
+		&ConfigV2{
+			ReceiverSettings: models.ReceiverSettings{
+				TypeVal: typeStr,
+				NameVal: "vmmetrics/customname",
+			},
+			ScrapeInterval:    5 * time.Second,
+			MetricPrefix:      "testmetric",
+			MountPoint:        "/mountpoint",
+			ProcessMountPoint: "/proc",
+		})
+}

receiver/vmmetricsreceiver/factory.go

@@ -0,0 +1,89 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// 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 vmmetricsreceiver
+
+import (
+	"context"
+
+	"go.uber.org/zap"
+
+	"github.com/open-telemetry/opentelemetry-service/consumer"
+	"github.com/open-telemetry/opentelemetry-service/models"
+	"github.com/open-telemetry/opentelemetry-service/receiver"
+)
+
+// This file implements config V2 for Prometheus receiver.
+
+var _ = receiver.RegisterReceiverFactory(&ReceiverFactory{})
+
+const (
+	// The value of "type" key in configuration.
+	typeStr = "vmmetrics"
+)
+
+// ReceiverFactory is the factory for receiver.
+type ReceiverFactory struct {
+}
+
+// Type gets the type of the Receiver config created by this factory.
+func (f *ReceiverFactory) Type() string {
+	return typeStr
+}
+
+// CustomUnmarshaler returns custom unmarshaler for this config.
+func (f *ReceiverFactory) CustomUnmarshaler() receiver.CustomUnmarshaler {
+	return nil
+}
+
+// CreateDefaultConfig creates the default configuration for receiver.
+func (f *ReceiverFactory) CreateDefaultConfig() models.Receiver {
+	return &ConfigV2{
+		ReceiverSettings: models.ReceiverSettings{
+			TypeVal: typeStr,
+			NameVal: typeStr,
+		},
+	}
+}
+
+// CreateTraceReceiver creates a trace receiver based on provided config.
+func (f *ReceiverFactory) CreateTraceReceiver(
+	ctx context.Context,
+	logger *zap.Logger,
+	cfg models.Receiver,
+	nextConsumer consumer.TraceConsumer,
+) (receiver.TraceReceiver, error) {
+	// Prometheus does not support traces
+	return nil, models.ErrDataTypeIsNotSupported
+}
+
+// CreateMetricsReceiver creates a metrics receiver based on provided config.
+func (f *ReceiverFactory) CreateMetricsReceiver(
+	logger *zap.Logger,
+	config models.Receiver,
+	consumer consumer.MetricsConsumer,
+) (receiver.MetricsReceiver, error) {
+
+	cfg := config.(*ConfigV2)
+
+	vmc, err := NewVMMetricsCollector(cfg.ScrapeInterval, cfg.MountPoint, cfg.ProcessMountPoint, cfg.MetricPrefix, consumer)
+	if err != nil {
+		return nil, err
+	}
+
+	vmr := &Receiver{
+		vmc: vmc,
+	}
+	return vmr, nil
+}

receiver/vmmetricsreceiver/factory_test.go

@@ -0,0 +1,47 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// 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 vmmetricsreceiver
+
+import (
+	"context"
+	"testing"
+
+	"go.uber.org/zap"
+
+	"github.com/open-telemetry/opentelemetry-service/models"
+	"github.com/open-telemetry/opentelemetry-service/receiver"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCreateDefaultConfig(t *testing.T) {
+	factory := receiver.GetReceiverFactory(typeStr)
+	cfg := factory.CreateDefaultConfig()
+	assert.NotNil(t, cfg, "failed to create default config")
+}
+
+func TestCreateReceiver(t *testing.T) {
+	factory := receiver.GetReceiverFactory(typeStr)
+	cfg := factory.CreateDefaultConfig()
+
+	tReceiver, err := factory.CreateTraceReceiver(context.Background(), zap.NewNop(), cfg, nil)
+	assert.Equal(t, err, models.ErrDataTypeIsNotSupported)
+	assert.Nil(t, tReceiver)
+
+	// The default config does not provide scrape_config so we expect that metrics receiver
+	// creation must also fail.
+	mReceiver, err := factory.CreateMetricsReceiver(zap.NewNop(), cfg, nil)
+	assert.Nil(t, err)
+	assert.NotNil(t, mReceiver)
+}

receiver/vmmetricsreceiver/metrics_receiver.go

@@ -15,13 +15,14 @@
 package vmmetricsreceiver
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"runtime"
 	"sync"
 	"time"
 
+	"github.com/open-telemetry/opentelemetry-service/receiver"
+
 	"github.com/spf13/viper"
 
 	"github.com/open-telemetry/opentelemetry-service/consumer"
@@ -76,8 +77,15 @@ func New(v *viper.Viper, consumer consumer.MetricsConsumer) (*Receiver, error) {
 	return vmr, nil
 }
 
+const metricsSource string = "VMMetrics"
+
+// MetricsSource returns the name of the metrics data source.
+func (vmr *Receiver) MetricsSource() string {
+	return metricsSource
+}
+
 // StartMetricsReception scrapes VM metrics based on the OS platform.
-func (vmr *Receiver) StartMetricsReception(ctx context.Context, asyncErrorChan chan<- error) error {
+func (vmr *Receiver) StartMetricsReception(host receiver.Host) error {
 	vmr.mu.Lock()
 	defer vmr.mu.Unlock()
 
@@ -97,7 +105,7 @@ func (vmr *Receiver) StartMetricsReception(ctx context.Context, asyncErrorChan c
 }
 
 // StopMetricsReception stops and cancels the underlying VM metrics scrapers.
-func (vmr *Receiver) StopMetricsReception(ctx context.Context) error {
+func (vmr *Receiver) StopMetricsReception() error {
 	vmr.mu.Lock()
 	defer vmr.mu.Unlock()
 

receiver/vmmetricsreceiver/testdata/config.yaml

@@ -0,0 +1,19 @@
+receivers:
+  vmmetrics:
+  vmmetrics/customname:
+    scrape_interval: 5s
+    mount_point: /mountpoint
+    process_mount_point: /proc
+    metric_prefix: testmetric
+
+processors:
+  exampleprocessor:
+
+exporters:
+  exampleexporter:
+
+pipelines:
+  traces:
+    receivers: [vmmetrics]
+    processors: [exampleprocessor]
+    exporters: [exampleexporter]