Merge branch 'master' into ext-proc-server

Author: kannanjgithub

xds/src/main/java/io/grpc/xds/internal/extproc/ExternalProcessorServerInterceptorMetricInstruments.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2026 The gRPC 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 io.grpc.xds.internal.extproc;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.collect.ImmutableList;
+import io.grpc.DoubleHistogramMetricInstrument;
+import io.grpc.MetricInstrumentRegistry;
+import io.grpc.internal.GrpcUtil;
+import java.util.List;
+
+/**
+ * Holds metric instrument definitions for server-side external processing.
+ */
+public final class ExternalProcessorServerInterceptorMetricInstruments {
+  @VisibleForTesting
+  public static DoubleHistogramMetricInstrument clientHeadersDuration;
+  @VisibleForTesting
+  public static DoubleHistogramMetricInstrument clientHalfCloseDuration;
+  @VisibleForTesting
+  public static DoubleHistogramMetricInstrument serverHeadersDuration;
+  @VisibleForTesting
+  public static DoubleHistogramMetricInstrument serverTrailersDuration;
+
+  // Copied from io.grpc.opentelemetry.internal.OpenTelemetryConstants.LATENCY_BUCKETS
+  private static final List<Double> LATENCY_BUCKETS = ImmutableList.of(
+      0d,     0.00001d, 0.00005d, 0.0001d, 0.0003d, 0.0006d, 0.0008d, 0.001d, 0.002d,
+      0.003d, 0.004d,   0.005d,   0.006d,  0.008d,  0.01d,   0.013d,  0.016d, 0.02d,
+      0.025d, 0.03d,    0.04d,    0.05d,   0.065d,  0.08d,   0.1d,    0.13d,  0.16d,
+      0.2d,   0.25d,    0.3d,     0.4d,    0.5d,    0.65d,   0.8d,    1d,     2d,
+      5d,     10d,      20d,      50d,     100d);
+
+  static {
+    initMetricInstruments();
+  }
+
+  public static synchronized void initMetricInstruments() {
+    if (GrpcUtil.getFlag("GRPC_EXPERIMENTAL_XDS_EXT_PROC_ON_SERVER", false)) {
+      if (clientHeadersDuration == null) {
+        MetricInstrumentRegistry registry = MetricInstrumentRegistry.getDefaultRegistry();
+
+        clientHeadersDuration = registry.registerDoubleHistogram(
+            "grpc.server_ext_proc.client_headers_duration",
+            "Time between when the ext_proc filter sees the client's headers and when "
+                + "it allows those headers to continue on to the next filter",
+            "s",
+            LATENCY_BUCKETS,
+            ImmutableList.of(),
+            ImmutableList.of(),
+            true);
+
+        clientHalfCloseDuration = registry.registerDoubleHistogram(
+            "grpc.server_ext_proc.client_half_close_duration",
+            "Time between when the ext_proc filter sees the client's half-close and when "
+                + "it allows that half-close to continue on to the next filter",
+            "s",
+            LATENCY_BUCKETS,
+            ImmutableList.of(),
+            ImmutableList.of(),
+            true);
+
+        serverHeadersDuration = registry.registerDoubleHistogram(
+            "grpc.server_ext_proc.server_headers_duration",
+            "Time between when the ext_proc filter sees the server's headers and when "
+                + "it allows those headers to continue on to the next filter",
+            "s",
+            LATENCY_BUCKETS,
+            ImmutableList.of(),
+            ImmutableList.of(),
+            true);
+
+        serverTrailersDuration = registry.registerDoubleHistogram(
+            "grpc.server_ext_proc.server_trailers_duration",
+            "Time between when the ext_proc filter sees the server's trailers and when "
+                + "it allows those trailers to continue on to the next filter",
+            "s",
+            LATENCY_BUCKETS,
+            ImmutableList.of(),
+            ImmutableList.of(),
+            true);
+      }
+    }
+  }
+
+  private ExternalProcessorServerInterceptorMetricInstruments() {}
+}