make sure we can handle a null component when throttling. (#47)

* make sure we can handle a null component when throttling. * Update splunk-otel-android/src/test/java/com/splunk/rum/ThrottlingExporterTest.java * inline an unused test method
signalfx · Jun 23, 2021 · 68d2949 · 68d2949
1 parent c7aaf14
commit 68d2949
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Showing 2 changed files with 20 additions and 4 deletions.
diff --git a/splunk-otel-android/src/main/java/com/splunk/rum/ThrottlingExporter.java b/splunk-otel-android/src/main/java/com/splunk/rum/ThrottlingExporter.java
@@ -39,6 +39,7 @@ class ThrottlingExporter implements SpanExporter {
     private final long windowSizeInNanos;
     private final int maxSpansInWindow;
     // note: no need to make this thread-safe since it will only ever be called from the BatchSpanProcessor worker thread.
+    // the implementation here needs to support null keys, or we'd need to use a default component value.
     private final Map<String, Window> categoryToWindow = new HashMap<>();
 
     private ThrottlingExporter(Builder builder) {
@@ -89,7 +90,12 @@ boolean aboveLimit(SpanData spanData) {
 
             // remove oldest entries until the window shrinks to the configured size
             while (true) {
-                long first = timestamps.peekFirst();
+                Long first = timestamps.peekFirst();
+                //this shouldn't happen, due to the single-threaded nature of things here, but
+                //just to be on the safe side, don't blow up if something has cleared out the window.
+                if (first == null) {
+                    break;
+                }
                 if (endNanos - first < windowSizeInNanos) {
                     break;
                 }

diff --git a/splunk-otel-android/src/test/java/com/splunk/rum/ThrottlingExporterTest.java b/splunk-otel-android/src/test/java/com/splunk/rum/ThrottlingExporterTest.java
@@ -117,7 +117,12 @@ public void shouldCountDifferentComponentsSeparately() {
                 span("ui", now.plus(10, ChronoUnit.SECONDS)),
                 span("ui", now.plus(15, ChronoUnit.SECONDS)),
                 span("ui", now.plus(20, ChronoUnit.SECONDS)),
-                span("error", now.plus(25, ChronoUnit.SECONDS))
+                span("error", now.plus(25, ChronoUnit.SECONDS)),
+                //user-generated spans probably won't have a "component" attribute at all.
+                span(null, now.plus(30, ChronoUnit.SECONDS)),
+                span(null, now.plus(35, ChronoUnit.SECONDS)),
+                span(null, now.plus(40, ChronoUnit.SECONDS)),
+                span(null, now.plus(45, ChronoUnit.SECONDS))
         );
 
         // when
@@ -130,7 +135,11 @@ public void shouldCountDifferentComponentsSeparately() {
                 spanData.get(2),
                 spanData.get(3),
                 // idx=4 will be skipped because it's the 3rd component=ui span in the last 15 secs
-                spanData.get(5)
+                spanData.get(5),
+                spanData.get(6),
+                spanData.get(7),
+                // idx = 8 will be skipped because it's the 3rd no-component span in the 2-span, 15s window
+                spanData.get(9)
         ));
     }
 
@@ -210,4 +219,5 @@ private static SpanData span(String component, Instant endTime) {
                 .setAttributes(Attributes.of(SplunkRum.COMPONENT_KEY, component))
                 .build();
     }
-}
+
+}