Move constants into own package

auto/auto.go

@@ -24,9 +24,9 @@ import (
 
 // Detect sequentially runs resource detection from environment varibales, AWS, and GCP.
 func Detect(ctx context.Context) (*resource.Resource, error) {
-	return resource.DetectAll(ctx,
-		resource.FromEnvVars,
+	return resource.ChainedDetector(
+		resource.FromEnv,
 		gcp.DetectGCEInstance,
 		aws.DetectEC2Instance,
-	)
+	)(ctx)
 }

aws/aws.go

@@ -17,17 +17,12 @@ package aws
 import (
 	"context"
 
+	"contrib.go.opencensus.io/resource/resourcekeys"
 	"github.com/aws/aws-sdk-go/aws/ec2metadata"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"go.opencensus.io/resource"
 )
 
-const (
-	KeyAccountID  = "aws.com/account_id"
-	KeyRegion     = "aws.com/region"
-	KeyInstanceID = "aws.com/ec2/instance_id"
-)
-
 func DetectEC2Instance(context.Context) (*resource.Resource, error) {
 	c := ec2metadata.New(session.New())
 	if !c.Available() {
@@ -38,11 +33,11 @@ func DetectEC2Instance(context.Context) (*resource.Resource, error) {
 		return nil, err
 	}
 	return &resource.Resource{
-		Type: "aws.com/ec2/instance",
+		Type: resourcekeys.AWSTypeEC2Instance,
 		Tags: map[string]string{
-			KeyRegion:     doc.Region,
-			KeyAccountID:  doc.AccountID,
-			KeyInstanceID: doc.InstanceID,
+			resourcekeys.AWSKeyEC2Region:     doc.Region,
+			resourcekeys.AWSKeyEC2AccountID:  doc.AccountID,
+			resourcekeys.AWSKeyEC2InstanceID: doc.InstanceID,
 		},
 	}, nil
 }

gcp/gcp.go

@@ -20,46 +20,34 @@ import (
 	"strings"
 
 	"cloud.google.com/go/compute/metadata"
+	"contrib.go.opencensus.io/resource/resourcekeys"
 	"go.opencensus.io/resource"
 )
 
-const (
-	KeyProjectID   = "cloud.google.com/project_id"
-	KeyZone        = "cloud.google.com/zone"
-	KeyInstanceID  = "cloud.google.com/gce/instance_id"
-	KeyClusterName = "cloud.google.com/gce/attributes/cluster_name"
-)
-
 func DetectGCEInstance(context.Context) (*resource.Resource, error) {
 	if !metadata.OnGCE() {
 		return nil, nil
 	}
 	res := &resource.Resource{
-		Type: "cloud.google.com/gce/instance",
+		Type: resourcekeys.GCPTypeGCEInstance,
 		Tags: map[string]string{},
 	}
 	instanceID, err := metadata.InstanceID()
 	logError(err)
 	if instanceID != "" {
-		res.Tags[KeyInstanceID] = instanceID
+		res.Tags[resourcekeys.GCPKeyGCEInstanceID] = instanceID
 	}
 
 	projectID, err := metadata.ProjectID()
 	logError(err)
 	if projectID != "" {
-		res.Tags[KeyProjectID] = projectID
+		res.Tags[resourcekeys.GCPKeyGCEProjectID] = projectID
 	}
 
 	zone, err := metadata.Zone()
 	logError(err)
 	if zone != "" {
-		res.Tags[KeyZone] = zone
-	}
-
-	clusterName, err := metadata.InstanceAttributeValue("cluster-name")
-	logError(err)
-	if clusterName != "" {
-		res.Tags[KeyClusterName] = strings.TrimSpace(clusterName)
+		res.Tags[resourcekeys.GCPKeyGCEZone] = zone
 	}
 
 	return res, nil

resourcekeys/const.go

@@ -0,0 +1,49 @@
+// Copyright 2018, 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 resourcekeys contains well known type and label keys for resources.
+package resourcekeys
+
+// Constants for Kubernetes resources.
+const (
+	K8STypeContainer = "k8s.io/container"
+
+	// A uniquely identifying name for the Kubernetes cluster. Kubernetes
+	// does not have cluster names as an internal concept so this may be
+	// set to any meaningful value within the environment. For example,
+	// GKE clusters have a name which can be used for this label.
+	K8SKeyClusterName   = "k8s.io/cluster/name"
+	K8SKeyNamespaceName = "k8s.io/namespace/name"
+	K8SKeyPodName       = "k8s.io/pod/name"
+	K8SKeyContainerName = "k8s.io/container/name"
+)
+
+// Constants for AWS resources.
+const (
+	AWSTypeEC2Instance = "aws.com/ec2/instance"
+
+	AWSKeyEC2AccountID  = "aws.com/ec2/account_id"
+	AWSKeyEC2Region     = "aws.com/ec2/region"
+	AWSKeyEC2InstanceID = "aws.com/ec2/instance_id"
+)
+
+// Constants for GCP resources.
+const (
+	GCPTypeGCEInstance = "cloud.google.com/gce/instance"
+
+	// ProjectID of the GCE VM. This is not the project ID of the used client credentials.
+	GCPKeyGCEProjectID  = "cloud.google.com/gce/project_id"
+	GCPKeyGCEZone       = "cloud.google.com/gce/zone"
+	GCPKeyGCEInstanceID = "cloud.google.com/gce/instance_id"
+)