Hook up sampler (#810)

* add sampler

* add sampler

* fix order

* fix typos

* another typo

* spotless

Author: jackshirazi

custom/src/main/java/co/elastic/otel/ElasticAutoConfigurationCustomizerProvider.java

@@ -18,6 +18,7 @@
  */
 package co.elastic.otel;
 
+import co.elastic.otel.compositesampling.DynamicCompositeParentBasedTraceIdRatioBasedSampler;
 import co.elastic.otel.dynamicconfig.BlockableLogRecordExporter;
 import co.elastic.otel.dynamicconfig.BlockableMetricExporter;
 import co.elastic.otel.dynamicconfig.BlockableSpanExporter;
@@ -91,6 +92,7 @@ public void customize(AutoConfigurationCustomizer autoConfiguration) {
         (providerBuilder, properties) -> {
           CentralConfig.init(providerBuilder, properties);
           AgentLog.addSpanLoggingIfRequired(providerBuilder, properties);
+          providerBuilder.setSampler(DynamicCompositeParentBasedTraceIdRatioBasedSampler.INSTANCE);
           return providerBuilder;
         });
   }

custom/src/main/java/co/elastic/otel/dynamicconfig/CentralConfig.java

@@ -18,6 +18,7 @@
  */
 package co.elastic.otel.dynamicconfig;
 
+import co.elastic.otel.compositesampling.DynamicCompositeParentBasedTraceIdRatioBasedSampler;
 import co.elastic.otel.dynamicconfig.internal.OpampManager;
 import co.elastic.otel.logging.AgentLog;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
@@ -128,6 +129,7 @@ public static class Configs {
                   new DeactivateAllInstrumentations(),
                   new DeactivateInstrumentations(),
                   new LoggingLevel(),
+                  new SamplingRate(),
                   new PollingInterval())
               .collect(Collectors.toMap(ConfigOption::getConfigName, option -> option));
     }
@@ -299,6 +301,19 @@ void update(String configurationValue, OpampManager opampManager)
     }
   }
 
+  public static final class SamplingRate extends ConfigOption {
+    SamplingRate() {
+      super("sampling_rate", "1.0");
+    }
+
+    @Override
+    void update(String configurationValue, OpampManager opampManager)
+        throws IllegalArgumentException {
+      DynamicCompositeParentBasedTraceIdRatioBasedSampler.setRatio(
+          Double.parseDouble(configurationValue));
+    }
+  }
+
   public static final class PollingInterval extends ConfigOption {
     PollingInterval() {
       super("opamp_polling_interval", "30s");