[cluster] Use `alt_stat_name` for general observability purposes (access log, tracing, admin) (#15139)

* Re-purpose alt_stat_name for other observability use-cases: access logging, tracing, and admin dumps through a new ClusterInfo field, `observabilityName()`.

Signed-off-by: Asra Ali <asraa@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 5551e0a3e442cca24d76eeea76e8b9dc5f894303

envoy/admin/v3/clusters.proto

@@ -29,7 +29,7 @@ message Clusters {
 }
 
 // Details an individual cluster's current status.
-// [#next-free-field: 7]
+// [#next-free-field: 8]
 message ClusterStatus {
   option (udpa.annotations.versioning).previous_message_type = "envoy.admin.v2alpha.ClusterStatus";
 
@@ -80,6 +80,9 @@ message ClusterStatus {
 
   // :ref:`Circuit breaking <arch_overview_circuit_break>` settings of the cluster.
   config.cluster.v3.CircuitBreakers circuit_breakers = 6;
+
+  // Observability name of the cluster.
+  string observability_name = 7;
 }
 
 // Current state of a particular host.

envoy/admin/v4alpha/clusters.proto

@@ -29,7 +29,7 @@ message Clusters {
 }
 
 // Details an individual cluster's current status.
-// [#next-free-field: 7]
+// [#next-free-field: 8]
 message ClusterStatus {
   option (udpa.annotations.versioning).previous_message_type = "envoy.admin.v3.ClusterStatus";
 
@@ -80,6 +80,9 @@ message ClusterStatus {
 
   // :ref:`Circuit breaking <arch_overview_circuit_break>` settings of the cluster.
   config.cluster.v4alpha.CircuitBreakers circuit_breakers = 6;
+
+  // Observability name of the cluster.
+  string observability_name = 7;
 }
 
 // Current state of a particular host.

envoy/config/cluster/v3/cluster.proto

@@ -21,6 +21,7 @@ import "google/protobuf/wrappers.proto";
 
 import "xds/core/v3/collection_entry.proto";
 
+import "udpa/annotations/migrate.proto";
 import "udpa/annotations/security.proto";
 import "udpa/annotations/status.proto";
 import "udpa/annotations/versioning.proto";
@@ -683,11 +684,16 @@ message Cluster {
   // Any ``:`` in the cluster name will be converted to ``_`` when emitting statistics.
   string name = 1 [(validate.rules).string = {min_len: 1}];
 
-  // An optional alternative to the cluster name to be used while emitting stats.
-  // Any ``:`` in the name will be converted to ``_`` when emitting statistics. This should not be
-  // confused with :ref:`Router Filter Header
-  // <config_http_filters_router_x-envoy-upstream-alt-stat-name>`.
-  string alt_stat_name = 28;
+  // An optional alternative to the cluster name to be used for observability. This name is used
+  // emitting stats for the cluster and access logging the cluster name. This will appear as
+  // additional information in configuration dumps of a cluster's current status as
+  // :ref:`observability_name <envoy_v3_api_field_admin.v3.ClusterStatus.observability_name>`
+  // and as an additional tag "upstream_cluster.name" while tracing. Note: access logging using
+  // this field is presently enabled with runtime feature
+  // `envoy.reloadable_features.use_observable_cluster_name`. Any ``:`` in the name will be
+  // converted to ``_`` when emitting statistics. This should not be confused with :ref:`Router
+  // Filter Header <config_http_filters_router_x-envoy-upstream-alt-stat-name>`.
+  string alt_stat_name = 28 [(udpa.annotations.field_migrate).rename = "observability_name"];
 
   oneof cluster_discovery_type {
     // The :ref:`service discovery type <arch_overview_service_discovery_types>`

envoy/config/cluster/v4alpha/cluster.proto

@@ -694,11 +694,16 @@ message Cluster {
   // Any ``:`` in the cluster name will be converted to ``_`` when emitting statistics.
   string name = 1 [(validate.rules).string = {min_len: 1}];
 
-  // An optional alternative to the cluster name to be used while emitting stats.
-  // Any ``:`` in the name will be converted to ``_`` when emitting statistics. This should not be
-  // confused with :ref:`Router Filter Header
-  // <config_http_filters_router_x-envoy-upstream-alt-stat-name>`.
-  string alt_stat_name = 28;
+  // An optional alternative to the cluster name to be used for observability. This name is used
+  // emitting stats for the cluster and access logging the cluster name. This will appear as
+  // additional information in configuration dumps of a cluster's current status as
+  // :ref:`observability_name <envoy_v3_api_field_admin.v3.ClusterStatus.observability_name>`
+  // and as an additional tag "upstream_cluster.name" while tracing. Note: access logging using
+  // this field is presently enabled with runtime feature
+  // `envoy.reloadable_features.use_observable_cluster_name`. Any ``:`` in the name will be
+  // converted to ``_`` when emitting statistics. This should not be confused with :ref:`Router
+  // Filter Header <config_http_filters_router_x-envoy-upstream-alt-stat-name>`.
+  string observability_name = 28;
 
   oneof cluster_discovery_type {
     // The :ref:`service discovery type <arch_overview_service_discovery_types>`