Make description of Samplers Locale independent (#4887)

* Make description of Samplers Locale independent

* Switch from String.format to concatanation

* Moved description creation to constructor

sdk-extensions/jaeger-remote-sampler/src/main/java/io/opentelemetry/sdk/extension/trace/jaeger/sampler/RateLimitingSampler.java

@@ -18,6 +18,8 @@ import io.opentelemetry.sdk.trace.data.LinkData;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
 import io.opentelemetry.sdk.trace.samplers.SamplingResult;
+import java.text.DecimalFormat;
+import java.text.DecimalFormatSymbols;
 import java.util.List;
 
 /**
@@ -29,10 +31,10 @@ class RateLimitingSampler implements Sampler {
   static final AttributeKey<String> SAMPLER_TYPE = stringKey("sampler.type");
   static final AttributeKey<Double> SAMPLER_PARAM = doubleKey("sampler.param");
 
-  private final double maxTracesPerSecond;
   private final RateLimiter rateLimiter;
   private final SamplingResult onSamplingResult;
   private final SamplingResult offSamplingResult;
+  private final String description;
 
   /**
    * Creates rate limiting sampler.
@@ -40,13 +42,13 @@ class RateLimitingSampler implements Sampler {
    * @param maxTracesPerSecond the maximum number of sampled traces per second.
    */
   RateLimitingSampler(int maxTracesPerSecond) {
-    this.maxTracesPerSecond = maxTracesPerSecond;
     double maxBalance = maxTracesPerSecond < 1.0 ? 1.0 : maxTracesPerSecond;
     this.rateLimiter = new RateLimiter(maxTracesPerSecond, maxBalance, Clock.getDefault());
     Attributes attributes =
         Attributes.of(SAMPLER_TYPE, TYPE, SAMPLER_PARAM, (double) maxTracesPerSecond);
     this.onSamplingResult = SamplingResult.create(SamplingDecision.RECORD_AND_SAMPLE, attributes);
     this.offSamplingResult = SamplingResult.create(SamplingDecision.DROP, attributes);
+    description = "RateLimitingSampler{" + decimalFormat(maxTracesPerSecond) + "}";
   }
 
   @Override
@@ -62,11 +64,19 @@ class RateLimitingSampler implements Sampler {
 
   @Override
   public String getDescription() {
-    return String.format("RateLimitingSampler{%.2f}", maxTracesPerSecond);
+    return description;
   }
 
   @Override
   public String toString() {
     return getDescription();
   }
+
+  private static String decimalFormat(double value) {
+    DecimalFormatSymbols decimalFormatSymbols = DecimalFormatSymbols.getInstance();
+    decimalFormatSymbols.setDecimalSeparator('.');
+
+    DecimalFormat decimalFormat = new DecimalFormat("0.00", decimalFormatSymbols);
+    return decimalFormat.format(value);
+  }
 }

sdk-extensions/jaeger-remote-sampler/src/test/java/io/opentelemetry/sdk/extension/trace/jaeger/sampler/RateLimitingSamplerTest.java

@@ -17,6 +17,7 @@ import io.opentelemetry.context.Context;
 import io.opentelemetry.sdk.trace.samplers.SamplingDecision;
 import io.opentelemetry.sdk.trace.samplers.SamplingResult;
 import java.util.Collections;
+import java.util.Locale;
 import org.junit.jupiter.api.Test;
 
 class RateLimitingSamplerTest {
@@ -62,8 +63,14 @@ class RateLimitingSamplerTest {
   }
 
   @Test
-  void description() {
+  void descriptionShouldBeLocaleIndependent() {
     RateLimitingSampler sampler = new RateLimitingSampler(15);
+
+    // PL locale uses ',' as decimal separator
+    Locale.setDefault(Locale.forLanguageTag("PL"));
+    assertThat(sampler.getDescription()).isEqualTo("RateLimitingSampler{15.00}");
+
+    Locale.setDefault(Locale.ENGLISH);
     assertThat(sampler.getDescription()).isEqualTo("RateLimitingSampler{15.00}");
   }
 }

sdk/trace/src/main/java/io/opentelemetry/sdk/trace/samplers/TraceIdRatioBasedSampler.java

@@ -10,6 +10,8 @@ import io.opentelemetry.api.internal.OtelEncodingUtils;
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.sdk.trace.data.LinkData;
+import java.text.DecimalFormat;
+import java.text.DecimalFormatSymbols;
 import java.util.List;
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
@@ -52,7 +54,7 @@ final class TraceIdRatioBasedSampler implements Sampler {
 
   TraceIdRatioBasedSampler(double ratio, long idUpperBound) {
     this.idUpperBound = idUpperBound;
-    description = String.format("TraceIdRatioBased{%.6f}", ratio);
+    description = "TraceIdRatioBased{" + decimalFormat(ratio) + "}";
   }
 
   @Override
@@ -108,4 +110,12 @@ final class TraceIdRatioBasedSampler implements Sampler {
   private static long getTraceIdRandomPart(String traceId) {
     return OtelEncodingUtils.longFromBase16String(traceId, 16);
   }
+
+  private static String decimalFormat(double value) {
+    DecimalFormatSymbols decimalFormatSymbols = DecimalFormatSymbols.getInstance();
+    decimalFormatSymbols.setDecimalSeparator('.');
+
+    DecimalFormat decimalFormat = new DecimalFormat("0.000000", decimalFormatSymbols);
+    return decimalFormat.format(value);
+  }
 }

sdk/trace/src/test/java/io/opentelemetry/sdk/trace/samplers/TraceIdRatioBasedSamplerTest.java

@@ -19,6 +19,7 @@ import io.opentelemetry.sdk.trace.IdGenerator;
 import io.opentelemetry.sdk.trace.data.LinkData;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import org.junit.jupiter.api.Test;
 
 class TraceIdRatioBasedSamplerTest {
@@ -67,9 +68,15 @@ class TraceIdRatioBasedSamplerTest {
   }
 
   @Test
-  void getDescription() {
-    assertThat(Sampler.traceIdRatioBased(0.5).getDescription())
-        .isEqualTo(String.format("TraceIdRatioBased{%.6f}", 0.5));
+  void descriptionShouldBeLocaleIndependent() {
+    Sampler sampler = Sampler.traceIdRatioBased(0.5);
+
+    // PL locale uses ',' as decimal separator
+    Locale.setDefault(Locale.forLanguageTag("PL"));
+    assertThat(sampler.getDescription()).isEqualTo("TraceIdRatioBased{0.500000}");
+
+    Locale.setDefault(Locale.ENGLISH);
+    assertThat(sampler.getDescription()).isEqualTo("TraceIdRatioBased{0.500000}");
   }
 
   @Test