Integrate with core resource and known detectors (#84)

* Integrate with core resource and known detectors

Signed-off-by: Fabian Reinartz <freinartz@google.com>

* Fix typo

Signed-off-by: Fabian Reinartz <freinartz@google.com>

resource.go

@@ -0,0 +1,109 @@
+// Copyright 2019, OpenCensus 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 stackdriver // import "contrib.go.opencensus.io/exporter/stackdriver"
+
+import (
+	"contrib.go.opencensus.io/resource/resourcekeys"
+	"go.opencensus.io/resource"
+	monitoredrespb "google.golang.org/genproto/googleapis/api/monitoredres"
+)
+
+type resourceMap struct {
+	// Mapping from the input resource type to the monitored resource type in Stackdriver.
+	srcType, dstType string
+	// Mapping from Stackdriver monitored resource label to an OpenCensus resource label.
+	labels map[string]string
+}
+
+// Resource labels that are generally internal to the exporter.
+// Consider exposing these labels and a type identifier in the future to allow
+// for customization.
+const (
+	stackdriverLocation             = "contrib.opencensus.io/exporter/stackdriver/location"
+	stackdriverProjectID            = "contrib.opencensus.io/exporter/stackdriver/project_id"
+	stackdriverGenericTaskNamespace = "contrib.opencensus.io/exporter/stackdriver/generic_task/namespace"
+	stackdriverGenericTaskJob       = "contrib.opencensus.io/exporter/stackdriver/generic_task/job"
+	stackdriverGenericTaskID        = "contrib.opencensus.io/exporter/stackdriver/generic_task/task_id"
+)
+
+// Mappings for the well-known OpenCensus resources to applicable Stackdriver resources.
+var resourceMappings = []resourceMap{
+	{
+		srcType: resourcekeys.K8STypeContainer,
+		dstType: "k8s_container",
+		labels: map[string]string{
+			"project_id":     stackdriverProjectID,
+			"location":       stackdriverLocation,
+			"cluster_name":   resourcekeys.K8SKeyClusterName,
+			"namespace_name": resourcekeys.K8SKeyNamespaceName,
+			"pod_name":       resourcekeys.K8SKeyPodName,
+			"container_name": resourcekeys.K8SKeyContainerName,
+		},
+	},
+	{
+		srcType: resourcekeys.GCPTypeGCEInstance,
+		dstType: "gce_instance",
+		labels: map[string]string{
+			"project_id":  resourcekeys.GCPKeyGCEProjectID,
+			"instance_id": resourcekeys.GCPKeyGCEInstanceID,
+			"zone":        resourcekeys.GCPKeyGCEZone,
+		},
+	},
+	{
+		srcType: resourcekeys.AWSTypeEC2Instance,
+		dstType: "aws_ec2_instance",
+		labels: map[string]string{
+			"project_id":  stackdriverProjectID,
+			"instance_id": resourcekeys.AWSKeyEC2InstanceID,
+			"region":      resourcekeys.AWSKeyEC2Region,
+			"aws_account": resourcekeys.AWSKeyEC2AccountID,
+		},
+	},
+	// Fallback to generic task resource.
+	{
+		srcType: "",
+		dstType: "generic_task",
+		labels: map[string]string{
+			"project_id": stackdriverProjectID,
+			"location":   stackdriverLocation,
+			"namespace":  stackdriverGenericTaskNamespace,
+			"job":        stackdriverGenericTaskJob,
+			"task_id":    stackdriverGenericTaskID,
+		},
+	},
+}
+
+func DefaultMapResource(res *resource.Resource) *monitoredrespb.MonitoredResource {
+Outer:
+	for _, rm := range resourceMappings {
+		if res.Type != rm.srcType {
+			continue
+		}
+		result := &monitoredrespb.MonitoredResource{
+			Type:   rm.dstType,
+			Labels: make(map[string]string, len(rm.labels)),
+		}
+		for dst, src := range rm.labels {
+			if v, ok := res.Labels[src]; ok {
+				result.Labels[dst] = v
+			} else {
+				// A required label wasn't filled at all. Try subsequent mappings.
+				continue Outer
+			}
+		}
+		return result
+	}
+	return nil
+}

resource_test.go

@@ -0,0 +1,73 @@
+// Copyright 2019, OpenCensus 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 stackdriver // import "contrib.go.opencensus.io/exporter/stackdriver"
+
+import (
+	"fmt"
+	"testing"
+
+	"contrib.go.opencensus.io/resource/resourcekeys"
+	"github.com/google/go-cmp/cmp"
+	"go.opencensus.io/resource"
+	monitoredrespb "google.golang.org/genproto/googleapis/api/monitoredres"
+)
+
+func TestDefaultMapResource(t *testing.T) {
+	cases := []struct {
+		input *resource.Resource
+		want  *monitoredrespb.MonitoredResource
+	}{
+		// Verify that the mapping works and that we skip over the
+		// first mapping that doesn't apply.
+		{
+			input: &resource.Resource{
+				Type: resourcekeys.GCPTypeGCEInstance,
+				Labels: map[string]string{
+					resourcekeys.GCPKeyGCEProjectID:  "proj1",
+					resourcekeys.GCPKeyGCEInstanceID: "inst1",
+					resourcekeys.GCPKeyGCEZone:       "zone1",
+					"extra_key":                      "must be ignored",
+				},
+			},
+			want: &monitoredrespb.MonitoredResource{
+				Type: "gce_instance",
+				Labels: map[string]string{
+					"project_id":  "proj1",
+					"instance_id": "inst1",
+					"zone":        "zone1",
+				},
+			},
+		},
+		// No match due to missing key.
+		{
+			input: &resource.Resource{
+				Type: resourcekeys.GCPTypeGCEInstance,
+				Labels: map[string]string{
+					resourcekeys.GCPKeyGCEProjectID:  "proj1",
+					resourcekeys.GCPKeyGCEInstanceID: "inst1",
+				},
+			},
+			want: nil,
+		},
+	}
+	for i, c := range cases {
+		t.Run(fmt.Sprintf("case-%d", i), func(t *testing.T) {
+			got := DefaultMapResource(c.input)
+			if diff := cmp.Diff(got, c.want); diff != "" {
+				t.Errorf("Values differ -got +want: %s", diff)
+			}
+		})
+	}
+}

stackdriver.go

@@ -52,10 +52,14 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"os"
+	"path"
 	"time"
 
+	metadataapi "cloud.google.com/go/compute/metadata"
 	traceapi "cloud.google.com/go/trace/apiv2"
 	"contrib.go.opencensus.io/exporter/stackdriver/monitoredresource"
+	"go.opencensus.io/resource"
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/tag"
 	"go.opencensus.io/trace"
@@ -73,9 +77,22 @@ type Options struct {
 	// ProjectID is the identifier of the Stackdriver
 	// project the user is uploading the stats data to.
 	// If not set, this will default to your "Application Default Credentials".
-	// For details see: https://developers.google.com/accounts/docs/application-default-credentials
+	// For details see: https://developers.google.com/accounts/docs/application-default-credentials.
+	//
+	// It will be used in the project_id label of a Stackdriver monitored
+	// resource if the resource does not inherently belong to a specific
+	// project, e.g. on-premise resource like k8s_container or generic_task.
 	ProjectID string
 
+	// Location is the identifier of the GCP or AWS cloud region/zone in which
+	// the data for a resource is stored.
+	// If not set, it will default to the location provided by the metadata server.
+	//
+	// It will be used in the location label of a Stackdriver monitored resource
+	// if the resource does not inherently belong to a specific project, e.g.
+	// on-premise resource like k8s_container or generic_task.
+	Location string
+
 	// OnError is the hook to be called when there is
 	// an error uploading the stats or tracing data.
 	// If no custom hook is set, errors are logged.
@@ -153,6 +170,21 @@ type Options struct {
 	// Optional, but encouraged.
 	MonitoredResource monitoredresource.Interface
 
+	// ResourceDetector provides a hook to discover arbitrary resource information.
+	//
+	// The translation function provided in MapResource must be able to conver the
+	// the resource information to a Stackdriver monitored resource.
+	//
+	// If this field is unset, resource type and tags will automatically be discovered through
+	// the OC_RESOURCE_TYPE and OC_RESOURCE_LABELS environment variables.
+	ResourceDetector resource.Detector
+
+	// MapResource converts a OpenCensus resource to a Stackdriver monitored resource.
+	//
+	// If this field is unset, DefaultMapResource will be used which encodes a set of default
+	// conversions from auto-detected resources to well-known Stackdriver monitored resources.
+	MapResource func(*resource.Resource) *monitoredrespb.MonitoredResource
+
 	// MetricPrefix overrides the prefix of a Stackdriver metric display names.
 	// Optional. If unset defaults to "OpenCensus/".
 	// Deprecated: Provide GetMetricDisplayName to change the display name of
@@ -253,10 +285,45 @@ func NewExporter(o Options) (*Exporter, error) {
 		}
 		o.ProjectID = creds.ProjectID
 	}
+	if o.Location == "" {
+		ctx := o.Context
+		if ctx == nil {
+			ctx = context.Background()
+		}
+		zone, err := metadataapi.Zone()
+		if err != nil {
+			log.Printf("Setting Stackdriver default location failed: %s", err)
+		} else {
+			log.Printf("Setting Stackdriver default location to %q", zone)
+			o.Location = zone
+		}
+	}
 
 	if o.MonitoredResource != nil {
 		o.Resource = convertMonitoredResourceToPB(o.MonitoredResource)
 	}
+	if o.MapResource == nil {
+		o.MapResource = DefaultMapResource
+	}
+	if o.ResourceDetector != nil {
+		// For backwards-compatibility we still respect the deprecated resource field.
+		if o.Resource != nil {
+			return nil, errors.New("stackdriver: ResourceDetector must not be used in combination with deprecated resource fields")
+		}
+		res, err := o.ResourceDetector(o.Context)
+		if err != nil {
+			return nil, fmt.Errorf("stackdriver: detect resource: %s", err)
+		}
+		// Populate internal resource labels for defaulting project_id, location, and
+		// generic resource labels of applicable monitored resources.
+		res.Labels[stackdriverProjectID] = o.ProjectID
+		res.Labels[stackdriverLocation] = o.Location
+		res.Labels[stackdriverGenericTaskNamespace] = "default"
+		res.Labels[stackdriverGenericTaskJob] = path.Base(os.Args[0])
+		res.Labels[stackdriverGenericTaskID] = getTaskValue()
+
+		o.Resource = o.MapResource(res)
+	}
 
 	se, err := newStatsExporter(o)
 	if err != nil {

stats.go

@@ -25,13 +25,13 @@ import (
 	"sync"
 	"time"
 
-	"go.opencensus.io"
+	opencensus "go.opencensus.io"
 	"go.opencensus.io/stats"
 	"go.opencensus.io/stats/view"
 	"go.opencensus.io/tag"
 	"go.opencensus.io/trace"
 
-	"cloud.google.com/go/monitoring/apiv3"
+	monitoring "cloud.google.com/go/monitoring/apiv3"
 	"github.com/golang/protobuf/ptypes/timestamp"
 	"google.golang.org/api/option"
 	"google.golang.org/api/support/bundler"