Don't use static client ID to allow multiple xray samplers in same process, usually for testing. (#57)

Author: Anuraag Agrawal

aws-xray/src/awsTest/java/io/opentelemetry/contrib/aws/xray/AwsXrayRemoteSamplerIntegrationTest.java

@@ -10,6 +10,8 @@
 import io.opentelemetry.contrib.awsxray.AwsXrayRemoteSampler;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.IdGenerator;
+import io.opentelemetry.sdk.trace.samplers.Sampler;
+import io.opentelemetry.sdk.trace.samplers.SamplingResult;
 import java.time.Duration;
 import java.util.Collections;
 import org.junit.jupiter.api.Test;
@@ -49,29 +51,38 @@ class AwsXrayRemoteSamplerIntegrationTest {
 
   @Test
   void keepSampling() throws Exception {
-    AwsXrayRemoteSampler sampler =
+    // Initialize two samplers to try to see centralized reservoir behavior.
+    AwsXrayRemoteSampler sampler1 =
+        AwsXrayRemoteSampler.newBuilder(Resource.getDefault())
+            .setEndpoint("http://localhost:" + otelCollector.getMappedPort(2000))
+            .setPollingInterval(Duration.ofSeconds(5))
+            .build();
+
+    AwsXrayRemoteSampler sampler2 =
         AwsXrayRemoteSampler.newBuilder(Resource.getDefault())
             .setEndpoint("http://localhost:" + otelCollector.getMappedPort(2000))
             .setPollingInterval(Duration.ofSeconds(5))
             .build();
 
     try {
       while (true) {
-        logger.info(
-            "Sampling Decision: {}",
-            sampler
-                .shouldSample(
-                    Context.root(),
-                    IdGenerator.random().generateTraceId(),
-                    "cat-service",
-                    SpanKind.SERVER,
-                    Attributes.empty(),
-                    Collections.emptyList())
-                .getDecision());
+        logger.info("[Sampler 1] Sampling Decision: {}", doSample(sampler1).getDecision());
+        logger.info("[Sampler 2] Sampling Decision: {}", doSample(sampler2).getDecision());
         Thread.sleep(500);
       }
     } finally {
-      sampler.close();
+      sampler1.close();
+      sampler2.close();
     }
   }
+
+  private static SamplingResult doSample(Sampler sampler) {
+    return sampler.shouldSample(
+        Context.root(),
+        IdGenerator.random().generateTraceId(),
+        "cat-service",
+        SpanKind.SERVER,
+        Attributes.empty(),
+        Collections.emptyList());
+  }
 }

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/AwsXrayRemoteSampler.java

@@ -40,14 +40,13 @@ public final class AwsXrayRemoteSampler implements Sampler, Closeable {
   private static final Random RANDOM = new Random();
   private static final Logger logger = Logger.getLogger(AwsXrayRemoteSampler.class.getName());
 
-  // Unique per-process client ID, generated as a random string.
-  private static final String CLIENT_ID = generateClientId();
-
   private final Resource resource;
   private final Clock clock;
   private final Sampler initialSampler;
   private final XraySamplerClient client;
   private final ScheduledExecutorService executor;
+  // Unique per-sampler client ID, generated as a random string.
+  private final String clientId;
   private final long pollingIntervalNanos;
   private final int jitterNanos;
 
@@ -89,6 +88,8 @@ public static AwsXrayRemoteSamplerBuilder newBuilder(Resource resource) {
               return t;
             });
 
+    clientId = generateClientId();
+
     sampler = initialSampler;
 
     this.pollingIntervalNanos = pollingIntervalNanos;
@@ -123,7 +124,7 @@ private void getAndUpdateSampler() {
       if (!response.equals(previousRulesResponse)) {
         sampler =
             new XrayRulesSampler(
-                CLIENT_ID,
+                clientId,
                 resource,
                 clock,
                 initialSampler,

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/GetSamplingTargetsRequest.java

@@ -4,7 +4,6 @@
  */
 package io.opentelemetry.contrib.awsxray;
 
-import com.fasterxml.jackson.annotation.JsonFormat;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.google.auto.value.AutoValue;
@@ -47,10 +46,6 @@ static SamplingStatisticsDocument.Builder newBuilder() {
     abstract long getSampledCount();
 
     @JsonProperty("Timestamp")
-    @JsonFormat(
-        shape = JsonFormat.Shape.STRING,
-        pattern = "yyyy-MM-dd'T'HH:mm:ss",
-        timezone = "UTC")
     abstract Date getTimestamp();
 
     @AutoValue.Builder

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/JdkHttpClient.java

@@ -84,7 +84,7 @@ String fetchString(
       if (responseCode != 200) {
         logger.log(
             Level.FINE,
-            "Error reponse from "
+            "Error response from "
                 + urlStr
                 + " code ("
                 + responseCode

aws-xray/src/test/resources/get-sampling-targets-request.json

@@ -3,15 +3,15 @@
     {
       "RuleName":"Test",
       "ClientID":"ABCDEF1234567890ABCDEF10",
-      "Timestamp":"2021-06-21T06:46:07",
+      "Timestamp":1624257967000,
       "RequestCount":110,
       "SampledCount":30,
       "BorrowCount":20
     },
     {
       "RuleName":"polling-scorekeep",
       "ClientID":"ABCDEF1234567890ABCDEF11",
-      "Timestamp":"2018-07-07T00:20:06",
+      "Timestamp":1530922806000,
       "RequestCount":10500,
       "SampledCount":31,
       "BorrowCount":0