tomd: support sample rates for counters -- closes #10

Author: scarytom

src/main/java/com/timgroup/statsd/ConvenienceMethodProvidingStatsDClient.java

@@ -67,6 +67,11 @@ public final void time(String aspect, long timeInMs) {
         recordExecutionTime(aspect, timeInMs);
     }
 
+    @Override
+    public final void recordExecutionTime(String aspect, long timeInMs) {
+        recordExecutionTime(aspect, timeInMs, 1.0);
+    }
+
     @Override
     public void recordExecutionTimeToNow(String aspect, long systemTimeMillisAtStart) {
         time(aspect, Math.max(0, System.currentTimeMillis() - systemTimeMillisAtStart));

src/main/java/com/timgroup/statsd/NoOpStatsDClient.java

@@ -13,5 +13,5 @@ public final class NoOpStatsDClient extends ConvenienceMethodProvidingStatsDClie
     @Override public void recordGaugeValue(String aspect, long value) { }
     @Override public void recordGaugeDelta(String aspect, long delta) { }
     @Override public void recordSetEvent(String aspect, String value) { }
-    @Override public void recordExecutionTime(String aspect, long timeInMs) { }
+    @Override public void recordExecutionTime(String aspect, long timeInMs, double sampleRate) { }
 }

src/main/java/com/timgroup/statsd/NonBlockingStatsDClient.java

@@ -199,8 +199,8 @@ public void recordSetEvent(String aspect, String eventName) {
      *     the time in milliseconds
      */
     @Override
-    public void recordExecutionTime(String aspect, long timeInMs) {
-        send(messageFor(aspect, timeInMs, "ms"));
+    public void recordExecutionTime(String aspect, long timeInMs, double sampleRate) {
+        send(messageFor(aspect, timeInMs, "ms", sampleRate));
     }
 
     private String messageFor(String aspect, Object value, String type) {

src/main/java/com/timgroup/statsd/StatsDClient.java

@@ -140,6 +140,21 @@ public interface StatsDClient {
      */
     void recordExecutionTime(String aspect, long timeInMs);
 
+    /**
+     * Adjusts the specified counter by a given delta.
+     *
+     * <p>This method is non-blocking and is guaranteed not to throw an exception.</p>
+     *
+     * @param aspect
+     *     the name of the counter to adjust
+     * @param delta
+     *     the amount to adjust the counter by
+     * @param sampleRate
+     *     the sampling rate being employed. For example, a rate of 0.1 would tell StatsD that this timer is being sent
+     *     sampled every 1/10th of the time, so that it updates its timer_counters appropriately.
+     */
+    void recordExecutionTime(String aspect, long timeInMs, double sampleRate);
+
     /**
      * Records an execution time in milliseconds for the specified named operation. The execution
      * time is calculated as the delta between the specified start time and the current system

src/test/java/com/timgroup/statsd/NonBlockingStatsDClientTest.java

@@ -119,6 +119,14 @@ public void stop() throws Exception {
         assertThat(server.messagesReceived(), contains("my.prefix.mytime:123|ms"));
     }
 
+    @Test(timeout=5000L) public void
+    sends_timer_with_rate_to_statsd() throws Exception {
+        client.recordExecutionTime("mytime", 123L, 0.000123);
+        server.waitForMessage();
+
+        assertThat(server.messagesReceived(), contains("my.prefix.mytime:123|[email protected]"));
+    }
+
     @Test(timeout=5000L) public void
     sends_timer_to_statsd_based_on_specified_start_time_to_now() throws Exception {
         final long startTime = System.currentTimeMillis() - 1000L;