[pkg/otlp/attributes] Handle literal 'host' tag

.chloggen/mx-psi_literal-host.yaml

@@ -0,0 +1,16 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component (e.g. pkg/quantile)
+component: pkg/otlp/attributes
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Handle literal 'host' attribute to avoid double tagging.
+
+# The PR related to this change
+issues: []
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: This avoids double tagging when using `metrics::resource_attributes_as_tags` metrics, or in all cases for traces/logs.

pkg/otlp/attributes/source.go

@@ -29,6 +29,9 @@ const (
  AttributeDatadogHostname = "datadog.host.name"
  // AttributeK8sNodeName the datadog k8s node name attribute
  AttributeK8sNodeName = "k8s.node.name"
+ // Attribute host is a literal host tag.
+ // We check for this to avoid double tagging.
+ AttributeHost = "host"
 )
 
 func getClusterName(attrs pcommon.Map) (string, bool) {
@@ -48,15 +51,17 @@ func getClusterName(attrs pcommon.Map) (string, bool) {
 
 // hostnameFromAttributes tries to get a valid hostname from attributes by checking, in order:
 //
-// 1. a custom Datadog hostname provided by the "datadog.host.name" attribute
+// 1. the "host" attribute to avoid double tagging if present.
 //
-// 2. cloud provider specific hostname for AWS, Azure or GCP,
+// 2. a custom Datadog hostname provided by the "datadog.host.name" attribute
 //
-// 3. the Kubernetes node name (and cluster name if available),
+// 3. cloud provider specific hostname for AWS, Azure or GCP,
 //
-// 4. the cloud provider host ID and
+// 4. the Kubernetes node name (and cluster name if available),
 //
-// 5. the host.name attribute.
+// 5. the cloud provider host ID and
+//
+// 6. the host.name attribute.
 //
 // It returns a boolean value indicated if any name was found
 func hostnameFromAttributes(attrs pcommon.Map) (string, bool) {
@@ -92,6 +97,13 @@ func k8sHostnameFromAttributes(attrs pcommon.Map) (string, bool) {
 }
 
 func unsanitizedHostnameFromAttributes(attrs pcommon.Map) (string, bool) {
+ // Literal 'host' tag. Check and use to avoid double tagging.
+ if literalHost, ok := attrs.Get(AttributeHost); ok {
+ // Use even if not a string, so that we avoid double tagging if
+ // `resource_attributes_as_tags` is true and 'host' has a non-string value.
+ return literalHost.AsString(), true
+ }
+
  // Custom hostname: useful for overriding in k8s/cloud envs
  if customHostname, ok := attrs.Get(AttributeDatadogHostname); ok {
  return customHostname.Str(), true

pkg/otlp/attributes/source_test.go

@@ -27,6 +27,7 @@ import (
 )
 
 const (
+ testLiteralHost = "literal-host"
  testHostID = "example-host-id"
  testHostName = "example-host-name"
  testContainerID = "example-container-id"
@@ -46,6 +47,20 @@ func TestSourceFromAttrs(t *testing.T) {
  ok bool
  src source.Source
  }{
+ {
+ name: "literal 'host' tag",
+ attrs: testutils.NewAttributeMap(map[string]string{
+ AttributeHost: testLiteralHost,
+ AttributeDatadogHostname: testCustomName,
+ AttributeK8sNodeName: testNodeName,
+ conventions.AttributeK8SClusterName: testClusterName,
+ conventions.AttributeContainerID: testContainerID,
+ conventions.AttributeHostID: testHostID,
+ conventions.AttributeHostName: testHostName,
+ }),
+ ok: true,
+ src: source.Source{Kind: source.HostnameKind, Identifier: testLiteralHost},
+ },
  {
  name: "custom hostname",
  attrs: testutils.NewAttributeMap(map[string]string{
@@ -148,6 +163,14 @@ func TestSourceFromAttrs(t *testing.T) {
  }
 }
 
+func TestLiteralHostNonString(t *testing.T) {
+ attrs := pcommon.NewMap()
+ attrs.PutInt(AttributeHost, 1000)
+ src, ok := SourceFromAttrs(attrs)
+ assert.True(t, ok)
+ assert.Equal(t, source.Source{Kind: source.HostnameKind, Identifier: "1000"}, src)
+}
+
 func TestGetClusterName(t *testing.T) {
  // OpenTelemetry convention
  attrs := testutils.NewAttributeMap(map[string]string{