From bc797ce0678b475c46ed7e85ba2a20e0b59ccb6a Mon Sep 17 00:00:00 2001
From: YANYZP <yzp@google.com>
Date: Fri, 24 Jul 2020 15:17:24 -0400
Subject: [PATCH 1/3] first

---
 detectors/gcp/gke.go | 71 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 detectors/gcp/gke.go

diff --git a/detectors/gcp/gke.go b/detectors/gcp/gke.go
new file mode 100644
index 00000000000..c0a8c1db810
--- /dev/null
+++ b/detectors/gcp/gke.go
@@ -0,0 +1,71 @@
+// Copyright The 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 gcp
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"cloud.google.com/go/compute/metadata"
+
+	"go.opentelemetry.io/otel/api/kv"
+	"go.opentelemetry.io/otel/api/standard"
+	"go.opentelemetry.io/otel/sdk/resource"
+)
+
+// GKE collects resource information of GKE computing instances
+type GKE struct{}
+
+// compile time assertion that GCE implements the resource.Detector interface.
+var _ resource.Detector = (*GKE)(nil)
+
+// Detect detects associated resources when running in GKE environment.
+func (gke *GKE) Detect(ctx context.Context) (*resource.Resource, error) {
+	gcpDetecor := GCE{}
+	gceLablRes, err := gcpDetecor.Detect(ctx)
+
+	if os.Getenv("KUBERNETES_SERVICE_HOST") == "" {
+		return gceLablRes, err
+	}
+
+	var errInfo []string
+	if err != nil {
+		errInfo = append(errInfo, err.Error())
+	}
+
+	labels := []kv.KeyValue{
+		standard.K8SNamespaceNameKey.String(os.Getenv("NAMESPACE")),
+		standard.K8SPodNameKey.String(os.Getenv("HOSTNAME")),
+	}
+
+	if containerName := os.Getenv("CONTAINER_NAME"); containerName != "" {
+		labels = append(labels, standard.ContainerNameKey.String(containerName))
+	}
+
+	if clusterName, err := metadata.Get("cluster-name"); hasProblem(err) {
+		errInfo = append(errInfo, err.Error())
+	} else if clusterName != "" {
+		labels = append(labels, standard.K8SClusterNameKey.String(clusterName))
+	}
+
+	k8sLabelRes := resource.New(labels...)
+	var aggregatedErr error
+	if len(errInfo) > 0 {
+		aggregatedErr = fmt.Errorf("detecting GKE resources: %s", errInfo)
+	}
+
+	return resource.Merge(gceLablRes, k8sLabelRes), aggregatedErr
+}

From ad57051b447685fef8bf2481fa12ce0743ddc2c9 Mon Sep 17 00:00:00 2001
From: YANYZP <yzp@google.com>
Date: Fri, 24 Jul 2020 15:21:11 -0400
Subject: [PATCH 2/3] used InstanceAttributeValue to get cluster name

---
 detectors/gcp/gke.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/detectors/gcp/gke.go b/detectors/gcp/gke.go
index c0a8c1db810..5734dac79fe 100644
--- a/detectors/gcp/gke.go
+++ b/detectors/gcp/gke.go
@@ -55,7 +55,7 @@ func (gke *GKE) Detect(ctx context.Context) (*resource.Resource, error) {
 		labels = append(labels, standard.ContainerNameKey.String(containerName))
 	}
 
-	if clusterName, err := metadata.Get("cluster-name"); hasProblem(err) {
+	if clusterName, err := metadata.InstanceAttributeValue("cluster-name"); hasProblem(err) {
 		errInfo = append(errInfo, err.Error())
 	} else if clusterName != "" {
 		labels = append(labels, standard.K8SClusterNameKey.String(clusterName))

From 7908e80594a63f1b7baf3c7f6c61872b30b95c36 Mon Sep 17 00:00:00 2001
From: YANYZP <yzp@google.com>
Date: Mon, 27 Jul 2020 09:49:45 -0400
Subject: [PATCH 3/3] updated changelog

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 439888200f2..e9f8d61f865 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ### Added
 
+- Create a detector that collects resources from GKE machines. (#139)
 - Create a detector that collects resources from GCE machines. (#132)
 - Add instrumentation for Kafka (github.com/Shopify/sarama). (#134)
 - Add links and status message for mock span. (#134)