special standalone sampler should only be used when tracing is disabled and appsec/iast are enabled

Author: jandro996

dd-trace-core/src/main/java/datadog/trace/common/sampling/ApmTracingDisabledSampler.java renamed to dd-trace-core/src/main/java/datadog/trace/common/sampling/AsmStandaloneSampler.java

@@ -11,20 +11,21 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * This class is designed to only allow 1 APM trace per minute for apm tracing disabled. The service
- * catalog and the billing need a continuous ingestion of at least at 1 trace per minute to consider
- * a service as being live and billable. In the absence of other products events, no APM traces must
- * be sent, so we need to let some regular APM traces go through.
+ * This class is designed to only allow 1 APM trace per minute as standalone ASM is only interested
+ * in the traces containing ASM events. But the service catalog and the billing need a continuous
+ * ingestion of at least at 1 trace per minute to consider a service as being live and billable. In
+ * the absence of ASM events, no APM traces must be sent, so we need to let some regular APM traces
+ * go through, even in the absence of ASM events.
  */
-public class ApmTracingDisabledSampler implements Sampler, PrioritySampler {
+public class AsmStandaloneSampler implements Sampler, PrioritySampler {
 
-  private static final Logger log = LoggerFactory.getLogger(ApmTracingDisabledSampler.class);
+  private static final Logger log = LoggerFactory.getLogger(AsmStandaloneSampler.class);
   private static final int RATE_IN_MILLISECONDS = 60000; // 1 minute
 
   private final AtomicLong lastSampleTime;
   private final Clock clock;
 
-  public ApmTracingDisabledSampler(final Clock clock) {
+  public AsmStandaloneSampler(final Clock clock) {
     this.clock = clock;
     this.lastSampleTime = new AtomicLong(clock.millis() - RATE_IN_MILLISECONDS);
   }
@@ -41,10 +42,10 @@ public <T extends CoreSpan<T>> void setSamplingPriority(final T span) {
 
     if (shouldSample()) {
       log.debug("Set SAMPLER_KEEP for span {}", span.getSpanId());
-      span.setSamplingPriority(SAMPLER_KEEP, SamplingMechanism.DEFAULT);
+      span.setSamplingPriority(SAMPLER_KEEP, SamplingMechanism.APPSEC);
     } else {
       log.debug("Set SAMPLER_DROP for span {}", span.getSpanId());
-      span.setSamplingPriority(SAMPLER_DROP, SamplingMechanism.DEFAULT);
+      span.setSamplingPriority(SAMPLER_DROP, SamplingMechanism.APPSEC);
     }
   }
 

dd-trace-core/src/main/java/datadog/trace/common/sampling/Sampler.java

@@ -4,6 +4,7 @@
 import static datadog.trace.bootstrap.instrumentation.api.SamplerConstants.KEEP;
 
 import datadog.trace.api.Config;
+import datadog.trace.api.ProductActivation;
 import datadog.trace.api.TraceConfig;
 import datadog.trace.api.config.TracerConfig;
 import datadog.trace.api.sampling.PrioritySampling;
@@ -35,9 +36,11 @@ final class Builder {
     public static Sampler forConfig(final Config config, final TraceConfig traceConfig) {
       Sampler sampler;
       if (config != null) {
-        if (!config.isApmTracingEnabled()) {
+        if (!config.isApmTracingEnabled()
+            && (config.getAppSecActivation() == ProductActivation.FULLY_ENABLED
+                || config.getIastActivation() == ProductActivation.FULLY_ENABLED)) {
           log.debug("APM is disabled. Only 1 trace per minute will be sent.");
-          return new ApmTracingDisabledSampler(Clock.systemUTC());
+          return new AsmStandaloneSampler(Clock.systemUTC());
         }
         final Map<String, String> serviceRules = config.getTraceSamplingServiceRules();
         final Map<String, String> operationRules = config.getTraceSamplingOperationRules();

dd-trace-core/src/test/groovy/datadog/trace/common/sampling/ApmTracingDisabledSamplerTest.groovy renamed to dd-trace-core/src/test/groovy/datadog/trace/common/sampling/AsmStandaloneSamplerTest.groovy

@@ -7,7 +7,7 @@ import datadog.trace.api.sampling.PrioritySampling
 import java.time.Clock
 import java.util.concurrent.atomic.AtomicLong
 
-class ApmTracingDisabledSamplerTest extends DDCoreSpecification{
+class AsmStandaloneSamplerTest extends DDCoreSpecification{
 
   def writer = new ListWriter()
 
@@ -19,7 +19,7 @@ class ApmTracingDisabledSamplerTest extends DDCoreSpecification{
         current.get()
       }
     }
-    def sampler = new ApmTracingDisabledSampler(clock)
+    def sampler = new AsmStandaloneSampler(clock)
     def tracer = tracerBuilder().writer(writer).sampler(sampler).build()
 
     when:

dd-trace-core/src/test/groovy/datadog/trace/common/sampling/SamplerTest.groovy

@@ -5,15 +5,52 @@ import datadog.trace.test.util.DDSpecification
 
 class SamplerTest extends DDSpecification{
 
-  void "test that TimeSampler is selected when experimentalAppSecStandalone is enabled"() {
+  void "test that AsmStandaloneSampler is selected when apm tracing disabled and appsec enabled is enabled"() {
     setup:
     System.setProperty("dd.apm.tracing.enabled", "false")
+    System.setProperty("dd.appsec.enabled", "true")
     Config config = new Config()
 
     when:
     Sampler sampler = Sampler.Builder.forConfig(config, null)
 
     then:
-    sampler instanceof ApmTracingDisabledSampler
+    sampler instanceof AsmStandaloneSampler
+  }
+
+  void "test that AsmStandaloneSampler is selected when apm tracing disabled and iast enabled is enabled"() {
+    setup:
+    System.setProperty("dd.apm.tracing.enabled", "false")
+    System.setProperty("dd.iast.enabled", "true")
+    Config config = new Config()
+
+    when:
+    Sampler sampler = Sampler.Builder.forConfig(config, null)
+
+    then:
+    sampler instanceof AsmStandaloneSampler
+  }
+
+  void "test that AsmStandaloneSampler is not selected when apm tracing and asm not enabled"() {
+    setup:
+    System.setProperty("dd.apm.tracing.enabled", "false")
+    Config config = new Config()
+
+    when:
+    Sampler sampler = Sampler.Builder.forConfig(config, null)
+
+    then:
+    !(sampler instanceof AsmStandaloneSampler)
+  }
+
+  void "test that AsmStandaloneSampler is not selected when apm tracing and asm not enabled"() {
+    setup:
+    Config config = new Config()
+
+    when:
+    Sampler sampler = Sampler.Builder.forConfig(config, null)
+
+    then:
+    !(sampler instanceof AsmStandaloneSampler)
   }
 }