Add telemetry for the RUM injector

dd-java-agent/agent-bootstrap/src/test/groovy/datadog/trace/bootstrap/instrumentation/buffer/InjectingPipeOutputStreamTest.groovy

@@ -112,7 +112,7 @@ class InjectingPipeOutputStreamTest extends DDSpecification {
     piped.close()
 
     then:
-    counter.value == 12
+    counter.value == testBytes.length
     downstream.toByteArray() == testBytes
   }
 
@@ -130,29 +130,26 @@ class InjectingPipeOutputStreamTest extends DDSpecification {
     piped.close()
 
     then:
-    counter.value == 4
+    counter.value == testBytes.length
     downstream.toByteArray() == testBytes
   }
 
   def 'should count bytes correctly with multiple writes'() {
     setup:
-    def part1 = "test".getBytes("UTF-8")
-    def part2 = " ".getBytes("UTF-8")
-    def part3 = "content".getBytes("UTF-8")
-    def testBytes = "test content".getBytes("UTF-8")
+    def testBytes = "test content"
     def downstream = new ByteArrayOutputStream()
     def counter = new Counter()
     def piped = new InjectingPipeOutputStream(downstream, MARKER_BYTES, CONTEXT_BYTES, null, { long bytes -> counter.incr(bytes) }, null)
 
     when:
-    piped.write(part1)
-    piped.write(part2)
-    piped.write(part3)
+    piped.write(testBytes[0..4].getBytes("UTF-8"))
+    piped.write(testBytes[5..5].getBytes("UTF-8"))
+    piped.write(testBytes[6..-1].getBytes("UTF-8"))
     piped.close()
 
     then:
-    counter.value == 12
-    downstream.toByteArray() == testBytes
+    counter.value == testBytes.length()
+    downstream.toByteArray() == testBytes.getBytes("UTF-8")
   }
 
   def 'should be resilient to exceptions when onBytesWritten callback is null'() {

dd-java-agent/agent-bootstrap/src/test/groovy/datadog/trace/bootstrap/instrumentation/buffer/InjectingPipeWriterTest.groovy

@@ -121,63 +121,66 @@ class InjectingPipeWriterTest extends DDSpecification {
     def downstream = new StringWriter()
     def counter = new Counter()
     def piped = new InjectingPipeWriter(downstream, MARKER_CHARS, CONTEXT_CHARS, null, { long bytes -> counter.incr(bytes) }, null)
+    def testBytes = "test content"
 
     when:
-    piped.write("test content".toCharArray())
+    piped.write(testBytes.toCharArray())
     piped.close()
 
     then:
-    counter.value == 12
-    downstream.toString() == "test content"
+    counter.value == testBytes.length()
+    downstream.toString() == testBytes
   }
 
   def 'should count bytes correctly when writing characters individually'() {
     setup:
     def downstream = new StringWriter()
     def counter = new Counter()
     def piped = new InjectingPipeWriter(downstream, MARKER_CHARS, CONTEXT_CHARS, null, { long bytes -> counter.incr(bytes) }, null)
+    def testBytes = "test"
 
     when:
-    def content = "test"
-    for (int i = 0; i < content.length(); i++) {
-      piped.write((int) content.charAt(i))
+    for (int i = 0; i < testBytes.length(); i++) {
+      piped.write((int) testBytes.charAt(i))
     }
     piped.close()
 
     then:
-    counter.value == 4
-    downstream.toString() == "test"
+    counter.value == testBytes.length()
+    downstream.toString() == testBytes
   }
 
   def 'should count bytes correctly with multiple writes'() {
     setup:
     def downstream = new StringWriter()
     def counter = new Counter()
     def piped = new InjectingPipeWriter(downstream, MARKER_CHARS, CONTEXT_CHARS, null, { long bytes -> counter.incr(bytes) }, null)
+    def testBytes = "test content"
 
     when:
-    piped.write("test".toCharArray())
-    piped.write(" ".toCharArray())
-    piped.write("content".toCharArray())
+    piped.write(testBytes[0..4].toCharArray())
+    piped.write(testBytes[5..5].toCharArray())
+    piped.write(testBytes[6..-1].toCharArray())
     piped.close()
 
     then:
-    counter.value == 12
-    downstream.toString() == "test content"
+    counter.value == testBytes.length()
+    downstream.toString() == testBytes
   }
 
   def 'should be resilient to exceptions when onBytesWritten callback is null'() {
     setup:
     def downstream = new StringWriter()
     def piped = new InjectingPipeWriter(downstream, MARKER_CHARS, CONTEXT_CHARS)
+    def testBytes = "test content"
 
     when:
-    piped.write("test content".toCharArray())
+    piped.write(testBytes.toCharArray())
     piped.close()
 
     then:
     noExceptionThrown()
-    downstream.toString() == "test content"
+    downstream.toString() == testBytes
   }
 
   def 'should call timing callback when injection happens'() {

dd-java-agent/instrumentation/servlet/request-3/src/test/groovy/RumHttpServletResponseWrapperTest.groovy

@@ -25,7 +25,7 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
 
   void setup() {
     mockRequest.getServletContext() >> mockServletContext
-    mockServletContext.getEffectiveMajorVersion() >> 3
+    mockServletContext.getEffectiveMajorVersion() >> Integer.parseInt(SERVLET_VERSION)
     wrapper = new RumHttpServletResponseWrapper(mockRequest, mockResponse)
     RumInjector.setTelemetryCollector(mockTelemetryCollector)
   }
@@ -172,14 +172,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     }
     def wrappedStream = new WrappedServletOutputStream(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    wrappedStream.write("test".getBytes("UTF-8"))
-    wrappedStream.write("content".getBytes("UTF-8"))
+    wrappedStream.write(testBytes[0..5].getBytes("UTF-8"))
+    wrappedStream.write(testBytes[6..-1].getBytes("UTF-8"))
     wrappedStream.close()
 
     then:
-    1 * mockTelemetryCollector.onInjectionResponseSize(SERVLET_VERSION, 11)
+    1 * mockTelemetryCollector.onInjectionResponseSize(SERVLET_VERSION, testBytes.length())
   }
 
   void 'response sizes are reported by the InjectingPipeOutputStream callback'() {
@@ -190,14 +191,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     def onBytesWritten = Mock(LongConsumer)
     def stream = new InjectingPipeOutputStream(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    stream.write("test".getBytes("UTF-8"))
-    stream.write("content".getBytes("UTF-8"))
+    stream.write(testBytes[0..5].getBytes("UTF-8"))
+    stream.write(testBytes[6..-1].getBytes("UTF-8"))
     stream.close()
 
     then:
-    1 * onBytesWritten.accept(11)
+    1 * onBytesWritten.accept(testBytes.length())
   }
 
   void 'response sizes are reported by the InjectingPipeWriter callback'() {
@@ -208,14 +210,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     def onBytesWritten = Mock(LongConsumer)
     def writer = new InjectingPipeWriter(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    writer.write("test".toCharArray())
-    writer.write("content".toCharArray())
+    writer.write(testBytes[0..5].toCharArray())
+    writer.write(testBytes[6..-1].toCharArray())
     writer.close()
 
     then:
-    1 * onBytesWritten.accept(11)
+    1 * onBytesWritten.accept(testBytes.length())
   }
 
   void 'injection timing is reported by the InjectingPipeOutputStream callback'() {

dd-java-agent/instrumentation/servlet/request-5/src/test/groovy/RumHttpServletResponseWrapperTest.groovy

@@ -25,7 +25,7 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
 
   void setup() {
     mockRequest.getServletContext() >> mockServletContext
-    mockServletContext.getEffectiveMajorVersion() >> 5
+    mockServletContext.getEffectiveMajorVersion() >> Integer.parseInt(SERVLET_VERSION)
     wrapper = new RumHttpServletResponseWrapper(mockRequest, mockResponse)
     RumInjector.setTelemetryCollector(mockTelemetryCollector)
   }
@@ -172,14 +172,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     }
     def wrappedStream = new WrappedServletOutputStream(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    wrappedStream.write("test".getBytes("UTF-8"))
-    wrappedStream.write("content".getBytes("UTF-8"))
+    wrappedStream.write(testBytes[0..5].getBytes("UTF-8"))
+    wrappedStream.write(testBytes[6..-1].getBytes("UTF-8"))
     wrappedStream.close()
 
     then:
-    1 * mockTelemetryCollector.onInjectionResponseSize(SERVLET_VERSION, 11)
+    1 * mockTelemetryCollector.onInjectionResponseSize(SERVLET_VERSION, testBytes.length())
   }
 
   void 'response sizes are reported by the InjectingPipeOutputStream callback'() {
@@ -190,14 +191,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     def onBytesWritten = Mock(LongConsumer)
     def stream = new InjectingPipeOutputStream(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    stream.write("test".getBytes("UTF-8"))
-    stream.write("content".getBytes("UTF-8"))
+    stream.write(testBytes[0..5].getBytes("UTF-8"))
+    stream.write(testBytes[6..-1].getBytes("UTF-8"))
     stream.close()
 
     then:
-    1 * onBytesWritten.accept(11)
+    1 * onBytesWritten.accept(testBytes.length())
   }
 
   void 'response sizes are reported by the InjectingPipeWriter callback'() {
@@ -208,14 +210,15 @@ class RumHttpServletResponseWrapperTest extends AgentTestRunner {
     def onBytesWritten = Mock(LongConsumer)
     def writer = new InjectingPipeWriter(
       downstream, marker, contentToInject, null, onBytesWritten, null)
+    def testBytes = "test content"
 
     when:
-    writer.write("test".toCharArray())
-    writer.write("content".toCharArray())
+    writer.write(testBytes[0..5].toCharArray())
+    writer.write(testBytes[6..-1].toCharArray())
     writer.close()
 
     then:
-    1 * onBytesWritten.accept(11)
+    1 * onBytesWritten.accept(testBytes.length())
   }
 
   void 'injection timing is reported by the InjectingPipeOutputStream callback'() {

dd-java-agent/testing/src/main/groovy/datadog/trace/agent/test/base/HttpServerTest.groovy

@@ -2236,14 +2236,28 @@ abstract class HttpServerTest<SERVER> extends WithHttpServer<SERVER> {
   def "test rum injection in head for mime #mime"() {
     setup:
     assumeTrue(testRumInjection())
+    def telemetryCollector = RumInjector.getTelemetryCollector()
     def request = new Request.Builder().url(server.address().resolve("gimme-$mime").toURL())
     .get().build()
+
     when:
     def response = client.newCall(request).execute()
+    def responseBody = response.body().string()
+    def finalSummary = telemetryCollector.summary()
+
     then:
     assert response.code() == 200
-    assert response.body().string().contains(new String(RumInjector.get().getSnippetBytes("UTF-8"), "UTF-8")) == expected
+    assert responseBody.contains(new String(RumInjector.get().getSnippetBytes("UTF-8"), "UTF-8")) == expected
     assert response.header("x-datadog-rum-injected") == (expected ? "1" : null)
+
+    // Check a few telemetry metrics
+    if (expected) {
+      assert finalSummary.contains("injectionSucceed=")
+      assert responseBody.length() > 0
+    } else {
+      assert finalSummary.contains("injectionSkipped=")
+    }
+
     where:
     mime   | expected
     "html" | true

dd-trace-core/src/main/java/datadog/trace/core/CoreTracer.java

@@ -705,11 +705,14 @@ private CoreTracer(
         config.isHealthMetricsEnabled()
             ? new MonitoringImpl(this.statsDClient, 10, SECONDS)
             : Monitoring.DISABLED;
-    healthMetrics =
-        config.isHealthMetricsEnabled()
-            ? new TracerHealthMetrics(this.statsDClient)
-            : HealthMetrics.NO_OP;
-    healthMetrics.start();
+
+    this.healthMetrics =
+        healthMetrics != null
+            ? healthMetrics
+            : (config.isHealthMetricsEnabled()
+                ? new TracerHealthMetrics(this.statsDClient)
+                : HealthMetrics.NO_OP);
+    this.healthMetrics.start();
 
     // Start RUM injector telemetry
     if (InstrumenterConfig.get().isRumEnabled()) {