Fix ingestion sampling

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/classicsdk/BytecodeUtilImpl.java

@@ -505,8 +505,10 @@ private static void track(
     }
 
     if (isPartOfTheCurrentTrace && applySampling && span instanceof ReadableSpan) {
-      long itemCount = getItemCount((ReadableSpan) span);
-      telemetryBuilder.setSampleRate(100.0f / itemCount);
+      Long itemCount = ((ReadableSpan) span).getAttribute(AiSemanticAttributes.ITEM_COUNT);
+      if (itemCount != null) {
+        telemetryBuilder.setSampleRate(100.0f / itemCount);
+      }
     }
 
     if (!isPartOfTheCurrentTrace && applySampling) {
@@ -574,11 +576,6 @@ private static boolean sample(String operationId, double samplingPercentage) {
     return SamplingScoreGeneratorV2.getSamplingScore(operationId) < samplingPercentage;
   }
 
-  private static long getItemCount(ReadableSpan span) {
-    Long itemCount = span.getAttribute(AiSemanticAttributes.ITEM_COUNT);
-    return itemCount == null ? 1L : itemCount;
-  }
-
   private static void selectivelySetTags(
       AbstractTelemetryBuilder telemetryBuilder, Map<String, String> sourceTags) {
     for (Map.Entry<String, String> entry : sourceTags.entrySet()) {

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/configuration/Configuration.java

@@ -65,6 +65,7 @@ private static boolean isEmpty(@Nullable String str) {
   public void validate() {
     instrumentation.logging.getSeverityThreshold();
     authentication.validate();
+    sampling.validate();
     preview.validate();
   }
 
@@ -168,6 +169,12 @@ public static class Sampling {
     @Deprecated @Nullable public Double limitPerSecond;
 
     public List<SamplingOverride> overrides = new ArrayList<>();
+
+    private void validate() {
+      for (SamplingOverride samplingOverride : overrides) {
+        samplingOverride.validate();
+      }
+    }
   }
 
   public static class SamplingPreview {

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/configuration/ConfigurationBuilder.java

@@ -257,6 +257,13 @@ private static void logConfigurationWarnings(Configuration config) {
       configurationLogger.warn(
           "\"clientsecret\" typed of AAD authentication has been deprecated since 3.5.0 GA. Please use \"user-assigned identity\" or \"system-assigned identity\" instead.");
     }
+    if (config.sampling.percentage != null && config.sampling.requestsPerSecond != null) {
+      configurationLogger.warn(
+          "Sampling \"requestsPerSecond\" and \"percentage\" should not be used at the same time."
+              + " Please remove one of them.");
+      config.sampling.percentage = null; // requestsPerSecond takes priority
+    }
+
     logWarningIfUsingInternalAttributes(config);
   }
 

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/sampling/AiSampler.java

@@ -76,6 +76,10 @@ public SamplingResult shouldSample(
               : parentlessDependencySamplingPercentage.get();
     }
 
+    if (sp == SamplingPercentage.USE_INGESTION_SAMPLING) {
+      return SamplingResult.recordAndSample();
+    }
+
     if (sp == 0) {
       return SamplingResult.drop();
     }

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/sampling/Samplers.java

@@ -20,7 +20,12 @@ public static Sampler getSampler(
       SamplingPercentage parentlessDependencySamplingPercentage = SamplingPercentage.fixed(100);
       sampler = new AiSampler(requestSamplingPercentage, parentlessDependencySamplingPercentage);
     } else if (sampling.percentage != null) {
-      SamplingPercentage samplingPercentage = SamplingPercentage.fixed(sampling.percentage);
+      SamplingPercentage samplingPercentage;
+      if (sampling.percentage == 100) {
+        samplingPercentage = SamplingPercentage.ingestion();
+      } else {
+        samplingPercentage = SamplingPercentage.fixed(sampling.percentage);
+      }
       sampler = new AiSampler(samplingPercentage, samplingPercentage);
     } else {
       throw new AssertionError("ConfigurationBuilder should have set the default sampling");

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/sampling/SamplingPercentage.java

@@ -12,6 +12,8 @@
 // the portal
 public interface SamplingPercentage {
 
+  long USE_INGESTION_SAMPLING = -1;
+
   double get();
 
   static SamplingPercentage fixed(double percentage) {
@@ -22,4 +24,8 @@ static SamplingPercentage fixed(double percentage) {
   static SamplingPercentage rateLimited(double targetPerSecondLimit) {
     return new RateLimitedSamplingPercentage(targetPerSecondLimit, 0.1);
   }
+
+  static SamplingPercentage ingestion() {
+    return () -> USE_INGESTION_SAMPLING;
+  }
 }

smoke-tests/apps/Sampling/src/smokeTest/java/com/microsoft/applicationinsights/smoketest/NoSamplingTest.java → smoke-tests/apps/Sampling/src/smokeTest/java/com/microsoft/applicationinsights/smoketest/IngestionSamplingTest.java

@@ -21,8 +21,8 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
-@UseAgent("applicationinsights-no-sampling.json")
-abstract class NoSamplingTest {
+@UseAgent("applicationinsights-ingestion-sampling.json")
+abstract class IngestionSamplingTest {
 
   @RegisterExtension static final SmokeTestExtension testing = SmokeTestExtension.create();
 
@@ -48,40 +48,40 @@ void testNoSampling() throws Exception {
     assertThat(messageEnvelopes.size()).isEqualTo(1000);
 
     for (Envelope requestEnvelope : requestEnvelopes) {
-      assertThat(requestEnvelope.getSampleRate()).isEqualTo(100.0f);
+      assertThat(requestEnvelope.getSampleRate()).isNull();
     }
     for (Envelope eventEnvelope : eventEnvelopes) {
-      assertThat(eventEnvelope.getSampleRate()).isEqualTo(100.0f);
+      assertThat(eventEnvelope.getSampleRate()).isNull();
     }
     for (Envelope messageEnvelope : messageEnvelopes) {
-      assertThat(messageEnvelope.getSampleRate()).isEqualTo(100.0f);
+      assertThat(messageEnvelope.getSampleRate()).isNull();
     }
   }
 
   @Environment(TOMCAT_8_JAVA_8)
-  static class Tomcat8Java8Test extends NoSamplingTest {}
+  static class Tomcat8Java8Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_8_OPENJ9)
-  static class Tomcat8Java8OpenJ9Test extends NoSamplingTest {}
+  static class Tomcat8Java8OpenJ9Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_11)
-  static class Tomcat8Java11Test extends NoSamplingTest {}
+  static class Tomcat8Java11Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_11_OPENJ9)
-  static class Tomcat8Java11OpenJ9Test extends NoSamplingTest {}
+  static class Tomcat8Java11OpenJ9Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_17)
-  static class Tomcat8Java17Test extends NoSamplingTest {}
+  static class Tomcat8Java17Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_19)
-  static class Tomcat8Java19Test extends NoSamplingTest {}
+  static class Tomcat8Java19Test extends IngestionSamplingTest {}
 
   @Environment(TOMCAT_8_JAVA_20)
-  static class Tomcat8Java20Test extends NoSamplingTest {}
+  static class Tomcat8Java20Test extends IngestionSamplingTest {}
 
   @Environment(WILDFLY_13_JAVA_8)
-  static class Wildfly13Java8Test extends NoSamplingTest {}
+  static class Wildfly13Java8Test extends IngestionSamplingTest {}
 
   @Environment(WILDFLY_13_JAVA_8_OPENJ9)
-  static class Wildfly13Java8OpenJ9Test extends NoSamplingTest {}
+  static class Wildfly13Java8OpenJ9Test extends IngestionSamplingTest {}
 }