fix: Only enable client side stats if the host agent is at least 7.65.0

Author: bric3

communication/src/main/java/datadog/communication/ddagent/AgentVersion.java

@@ -0,0 +1,62 @@
+package datadog.communication.ddagent;
+
+public class AgentVersion {
+
+  /**
+   * Checks if the given version string represents a version that is at least the specified major,
+   * minor, and patch version.
+   *
+   * @param version the version string to check (e.g., "7.65.0")
+   * @param minMajor minimum major version
+   * @param minMinor minimum minor version
+   * @param minPatch minimum patch version
+   * @return true if version is at least the specified minimum, false otherwise (including when
+   *     version is null or unparseable)
+   */
+  public static boolean isVersionAtLeast(String version, int minMajor, int minMinor, int minPatch) {
+    if (version == null || version.isEmpty()) {
+      return false;
+    }
+
+    try {
+      // Parse version string in format "major.minor.patch" (e.g., "7.65.0")
+      int majorDot = version.indexOf('.');
+      if (majorDot == -1) {
+        return false;
+      }
+
+      int major = Integer.parseInt(version.substring(0, majorDot));
+
+      if (major > minMajor) {
+        return true;
+      } else if (major < minMajor) {
+        return false;
+      }
+
+      // major == minMajor
+      int minorDot = version.indexOf('.', majorDot + 1);
+      if (minorDot == -1) {
+        return false;
+      }
+
+      int minor = Integer.parseInt(version.substring(majorDot + 1, minorDot));
+      if (minor > minMinor) {
+        return true;
+      } else if (minor < minMinor) {
+        return false;
+      }
+
+      // major == minMajor && minor == minMinor
+      // Find end of patch version (may have suffix like "-rc.1")
+      int patchEnd = minorDot + 1;
+      while (patchEnd < version.length() && Character.isDigit(version.charAt(patchEnd))) {
+        patchEnd++;
+      }
+
+      int patch = Integer.parseInt(version.substring(minorDot + 1, patchEnd));
+      return patch >= minPatch;
+    } catch (NumberFormatException | IndexOutOfBoundsException e) {
+      return false;
+    }
+  }
+}

communication/src/main/java/datadog/communication/ddagent/DDAgentFeaturesDiscovery.java

@@ -358,7 +358,8 @@ private static void discoverStatsDPort(final Map<String, Object> info) {
   public boolean supportsMetrics() {
     return metricsEnabled
         && null != discoveryState.metricsEndpoint
-        && discoveryState.supportsDropping;
+        && discoveryState.supportsDropping
+        && AgentVersion.isVersionAtLeast(discoveryState.version, 7, 65, 0);
   }
 
   public boolean supportsDebugger() {

communication/src/test/groovy/datadog/communication/ddagent/DDAgentFeaturesDiscoveryTest.groovy

@@ -498,6 +498,67 @@ class DDAgentFeaturesDiscoveryTest extends DDSpecification {
     )
   }
 
+  def "test metrics disabled for agent version below 7.65"() {
+    setup:
+    OkHttpClient client = Mock(OkHttpClient)
+    DDAgentFeaturesDiscovery features = new DDAgentFeaturesDiscovery(client, monitoring, agentUrl, true, true)
+
+    when: "agent version is below 7.65"
+    features.discover()
+
+    then:
+    1 * client.newCall(_) >> { Request request ->
+      def response = """
+      {
+        "version": "${version}",
+        "endpoints": ["/v0.5/traces", "/v0.6/stats"],
+        "client_drop_p0s": true,
+        "config": {}
+      }
+      """
+      infoResponse(request, response)
+    }
+    features.getMetricsEndpoint() == V6_METRICS_ENDPOINT
+    features.supportsDropping() == true
+    features.supportsMetrics() == expected
+
+    where:
+    version       | expected
+    "7.64.0"      | false
+    "7.64.9"      | false
+    "7.64.9-rc.1" | false
+    "7.65.0"      | true
+    "7.65.1"      | true
+    "7.70.0"      | true
+    "8.0.0"       | true
+  }
+
+  def "test metrics disabled for agent with unparseable version"() {
+    setup:
+    OkHttpClient client = Mock(OkHttpClient)
+    DDAgentFeaturesDiscovery features = new DDAgentFeaturesDiscovery(client, monitoring, agentUrl, true, true)
+
+    when: "agent version is unparseable"
+    features.discover()
+
+    then:
+    1 * client.newCall(_) >> { Request request ->
+      def response = """
+      {
+        "version": "${version}",
+        "endpoints": ["/v0.5/traces", "/v0.6/stats"],
+        "client_drop_p0s": true,
+        "config": {}
+      }
+      """
+      infoResponse(request, response)
+    }
+    !features.supportsMetrics()
+
+    where:
+    version << ["invalid", "7", "7.65", "", null]
+  }
+
   def "should send container id as header on the info request and parse the hash in the response"() {
     setup:
     OkHttpClient client = Mock(OkHttpClient)

communication/src/test/resources/agent-features/agent-info-with-client-dropping.json

@@ -1,5 +1,5 @@
 {
-  "version": "0.99.0",
+  "version": "7.65.0",
   "git_commit": "fab047e10",
   "build_date": "2020-12-04 15:57:06.74187 +0200 EET m=+0.029001792",
   "endpoints": [

dd-trace-core/src/test/groovy/datadog/trace/common/metrics/MetricsReliabilityTest.groovy

@@ -35,7 +35,7 @@ class MetricsReliabilityTest extends DDCoreSpecification {
     httpServer {
       handlers {
         get("/info") {
-          final def res = '{"endpoints":[' + (state.agentMetricsAvailable ? '"/v0.6/stats", ' : '') + '"/v0.4/traces"], "client_drop_p0s" : true}'
+          final def res = '{"version":"7.65.0","endpoints":[' + (state.agentMetricsAvailable ? '"/v0.6/stats", ' : '') + '"/v0.4/traces"], "client_drop_p0s" : true}'
           state.hash = Strings.sha256(res)
           response.send(res)
           state.latch.countDown()