[exporter/datadogexporter] Add Kubernetes conventions for hostnames (#…

…1919)

* Add Kubernetes conventions for hostnames

* Address linting issues

exporter/datadogexporter/metadata/host.go

@@ -26,6 +26,11 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/exporter/datadogexporter/utils/cache"
 )
 
+const (
+	AttributeDatadogHostname = "datadog.host.name"
+	AttributeK8sNodeName     = "k8s.node.name"
+)
+
 // GetHost gets the hostname according to configuration.
 // It checks in the following order
 // 1. Cache
@@ -65,12 +70,28 @@ func GetHost(logger *zap.Logger, cfg *config.Config) *string {
 
 // HostnameFromAttributes tries to get a valid hostname from attributes by checking, in order:
 //
-//   1. the container ID,
-//   2. the cloud provider host ID and
-//   3. the host.name attribute.
+//   1. a custom Datadog hostname provided by the "datadog.host.name" attribute
+//   2. the Kubernetes node name (and cluster name if available),
+//   3. the container ID,
+//   4. the cloud provider host ID and
+//   5. the host.name attribute.
 //
 //  It returns a boolean value indicated if any name was found
 func HostnameFromAttributes(attrs pdata.AttributeMap) (string, bool) {
+	// Custom hostname: useful for overriding in k8s/cloud envs
+	if customHostname, ok := attrs.Get(AttributeDatadogHostname); ok {
+		return customHostname.StringVal(), true
+	}
+
+	// Kubernetes: node-cluster if cluster name is available, else node
+	if k8sNodeName, ok := attrs.Get(AttributeK8sNodeName); ok {
+		if k8sClusterName, ok := attrs.Get(conventions.AttributeK8sCluster); ok {
+			return k8sNodeName.StringVal() + "-" + k8sClusterName.StringVal(), true
+		}
+		return k8sNodeName.StringVal(), true
+	}
+
+	// container id (e.g. from Docker)
 	if containerID, ok := attrs.Get(conventions.AttributeContainerID); ok {
 		return containerID.StringVal(), true
 	}
@@ -81,10 +102,12 @@ func HostnameFromAttributes(attrs pdata.AttributeMap) (string, bool) {
 		return ec2.HostnameFromAttributes(attrs)
 	}
 
+	// host id from cloud provider
 	if hostID, ok := attrs.Get(conventions.AttributeHostID); ok {
 		return hostID.StringVal(), true
 	}
 
+	// hostname from cloud provider or OS
 	if hostName, ok := attrs.Get(conventions.AttributeHostName); ok {
 		return hostName.StringVal(), true
 	}

exporter/datadogexporter/metadata/host_test.go

@@ -48,17 +48,46 @@ func TestHost(t *testing.T) {
 	assert.Equal(t, *host, osHostname)
 }
 
+const (
+	testHostID      = "example-host-id"
+	testHostName    = "example-host-name"
+	testContainerID = "example-container-id"
+	testClusterName = "clusterName"
+	testNodeName    = "nodeName"
+	testCustomName  = "example-custom-host-name"
+)
+
 func TestHostnameFromAttributes(t *testing.T) {
-	testHostID := "example-host-id"
-	testHostName := "example-host-name"
+	// Custom hostname
+	attrs := testutils.NewAttributeMap(map[string]string{
+		AttributeDatadogHostname:         testCustomName,
+		AttributeK8sNodeName:             testNodeName,
+		conventions.AttributeK8sCluster:  testClusterName,
+		conventions.AttributeContainerID: testContainerID,
+		conventions.AttributeHostID:      testHostID,
+		conventions.AttributeHostName:    testHostName,
+	})
+	hostname, ok := HostnameFromAttributes(attrs)
+	assert.True(t, ok)
+	assert.Equal(t, hostname, testCustomName)
+
+	// Container ID
+	attrs = testutils.NewAttributeMap(map[string]string{
+		conventions.AttributeContainerID: testContainerID,
+		conventions.AttributeHostID:      testHostID,
+		conventions.AttributeHostName:    testHostName,
+	})
+	hostname, ok = HostnameFromAttributes(attrs)
+	assert.True(t, ok)
+	assert.Equal(t, hostname, testContainerID)
 
 	// AWS cloud provider means relying on the EC2 function
-	attrs := testutils.NewAttributeMap(map[string]string{
+	attrs = testutils.NewAttributeMap(map[string]string{
 		conventions.AttributeCloudProvider: conventions.AttributeCloudProviderAWS,
 		conventions.AttributeHostID:        testHostID,
 		conventions.AttributeHostName:      testHostName,
 	})
-	hostname, ok := HostnameFromAttributes(attrs)
+	hostname, ok = HostnameFromAttributes(attrs)
 	assert.True(t, ok)
 	assert.Equal(t, hostname, testHostName)
 
@@ -76,5 +105,41 @@ func TestHostnameFromAttributes(t *testing.T) {
 	hostname, ok = HostnameFromAttributes(attrs)
 	assert.False(t, ok)
 	assert.Empty(t, hostname)
+}
+
+func TestHostnameKubernetes(t *testing.T) {
+	// Node name and cluster name
+	attrs := testutils.NewAttributeMap(map[string]string{
+		AttributeK8sNodeName:             testNodeName,
+		conventions.AttributeK8sCluster:  testClusterName,
+		conventions.AttributeContainerID: testContainerID,
+		conventions.AttributeHostID:      testHostID,
+		conventions.AttributeHostName:    testHostName,
+	})
+	hostname, ok := HostnameFromAttributes(attrs)
+	assert.True(t, ok)
+	assert.Equal(t, hostname, "nodeName-clusterName")
 
+	// Node name, no cluster name
+	attrs = testutils.NewAttributeMap(map[string]string{
+		AttributeK8sNodeName:             testNodeName,
+		conventions.AttributeContainerID: testContainerID,
+		conventions.AttributeHostID:      testHostID,
+		conventions.AttributeHostName:    testHostName,
+	})
+	hostname, ok = HostnameFromAttributes(attrs)
+	assert.True(t, ok)
+	assert.Equal(t, hostname, "nodeName")
+
+	// no node name, cluster name
+	attrs = testutils.NewAttributeMap(map[string]string{
+		conventions.AttributeK8sCluster:  testClusterName,
+		conventions.AttributeContainerID: testContainerID,
+		conventions.AttributeHostID:      testHostID,
+		conventions.AttributeHostName:    testHostName,
+	})
+	hostname, ok = HostnameFromAttributes(attrs)
+	assert.True(t, ok)
+	// cluster name gets ignored, fallback to next option
+	assert.Equal(t, hostname, testContainerID)
 }