feat(telemetry): add TelemetrySetup for installing the global OpenTelemetry providers

core/src/main/java/com/google/adk/telemetry/OtelHooks.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * 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 com.google.adk.telemetry;
+
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import io.opentelemetry.sdk.logs.LogRecordProcessor;
+import io.opentelemetry.sdk.metrics.export.MetricReader;
+import io.opentelemetry.sdk.trace.SpanProcessor;
+
+/**
+ * OpenTelemetry plumbing an application contributes to the providers {@link TelemetrySetup}
+ * installs.
+ *
+ * <p>The three signals are independent. A caller that only exports metrics sets only {@link
+ * #metricReaders()}; the signals it left out are empty, and {@link TelemetrySetup} builds no
+ * provider of its own for them.
+ */
+@AutoValue
+public abstract class OtelHooks {
+
+  /** Span processors to add to the tracer provider. */
+  public abstract ImmutableList<SpanProcessor> spanProcessors();
+
+  /** Metric readers to register with the meter provider. */
+  public abstract ImmutableList<MetricReader> metricReaders();
+
+  /** Log record processors to add to the logger provider. */
+  public abstract ImmutableList<LogRecordProcessor> logRecordProcessors();
+
+  /** Returns a builder whose three signals all start out empty. */
+  public static Builder builder() {
+    return new AutoValue_OtelHooks.Builder()
+        .spanProcessors(ImmutableList.of())
+        .metricReaders(ImmutableList.of())
+        .logRecordProcessors(ImmutableList.of());
+  }
+
+  /** Builder for {@link OtelHooks}. */
+  @AutoValue.Builder
+  public abstract static class Builder {
+
+    @CanIgnoreReturnValue
+    public abstract Builder spanProcessors(Iterable<? extends SpanProcessor> spanProcessors);
+
+    @CanIgnoreReturnValue
+    public abstract Builder metricReaders(Iterable<? extends MetricReader> metricReaders);
+
+    @CanIgnoreReturnValue
+    public abstract Builder logRecordProcessors(
+        Iterable<? extends LogRecordProcessor> logRecordProcessors);
+
+    public abstract OtelHooks build();
+  }
+}