3.11 compatibility improvements (#257)

* Improve compatibility with 3.11, by using deprecated Netty methods..

* Downgrade jackson-dataformat to 2.13.2

* Do not start /metrics endpoint if Cassandra version is older than 3.11.13

* Compare version with compateTo instead of isSupportedBy

management-api-agent-common/src/main/java/io/k8ssandra/metrics/http/NettyServerHandler.java

@@ -28,7 +28,7 @@ protected void channelRead0(ChannelHandlerContext ctx, HttpObject httpObject) th
         if (httpObject instanceof HttpRequest) {
             HttpRequest req = (HttpRequest) httpObject;
 
-            URI uri = new URI(req.uri());
+            URI uri = new URI(req.getUri());
             if (!uri.getPath().equals("/metrics")) {
                 // Send 404?
                 FullHttpResponse resp = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.NOT_FOUND);
@@ -51,21 +51,21 @@ protected void channelRead0(ChannelHandlerContext ctx, HttpObject httpObject) th
 
     private boolean writeResponse(HttpRequest request, ChannelHandlerContext ctx, String contentType) {
         // Decide whether to close the connection or not.
-        boolean keepAlive = HttpUtil.isKeepAlive(request);
+        boolean keepAlive = HttpHeaders.isKeepAlive(request); // Keep HttpHeaders instead of HttpUtil to get Netty 4.0.x compatibility
         // Build the response object.
         // TODO We should probably use something more performant.. copyBuffer for single thread (blocking) seems weird
         FullHttpResponse response = new DefaultFullHttpResponse(
-                HttpVersion.HTTP_1_1, request.decoderResult().isSuccess() ? HttpResponseStatus.OK : HttpResponseStatus.BAD_REQUEST,
+                HttpVersion.HTTP_1_1, request.getDecoderResult().isSuccess() ? HttpResponseStatus.OK : HttpResponseStatus.BAD_REQUEST,
                 Unpooled.copiedBuffer(writer.toString(), CharsetUtil.UTF_8));
 
-        response.headers().set(HttpHeaderNames.CONTENT_TYPE, contentType);
+        response.headers().set(HttpHeaders.Names.CONTENT_TYPE, contentType);
 
         if (keepAlive) {
             // Add 'Content-Length' header only for a keep-alive connection.
-            response.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, response.content().readableBytes());
+            response.headers().set(HttpHeaders.Names.CONTENT_LENGTH, response.content().readableBytes());
             // Add keep alive header as per:
             // - https://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01.html#Connection
-            response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
+            response.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
         }
 
         // Write the response.

management-api-agent-common/src/main/java/io/k8ssandra/metrics/interceptors/MetricsInterceptor.java

@@ -14,6 +14,8 @@
 import net.bytebuddy.matcher.ElementMatcher;
 import net.bytebuddy.matcher.ElementMatchers;
 import org.apache.cassandra.metrics.CassandraMetricsRegistry;
+import org.apache.cassandra.utils.CassandraVersion;
+import org.apache.cassandra.utils.FBUtilities;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -23,6 +25,8 @@ public class MetricsInterceptor
 {
     private static final Logger logger = LoggerFactory.getLogger(MetricsInterceptor.class);
 
+    private static final CassandraVersion MIN_CASSANDRA_VERSION = new CassandraVersion("3.11.13");
+
     public static ElementMatcher<? super TypeDescription> type()
     {
         return ElementMatchers.nameEndsWith(".CassandraDaemon");
@@ -34,6 +38,12 @@ public static Transformer transformer()
     }
 
     public static void intercept(@SuperCall Callable<Void> zuper) throws Exception {
+        CassandraVersion cassandraVersion = new CassandraVersion(FBUtilities.getReleaseVersionString());
+        if(MIN_CASSANDRA_VERSION.compareTo(cassandraVersion) > 0) {
+            logger.error("/metrics endpoint is not supported in versions older than {}", MIN_CASSANDRA_VERSION);
+            return;
+        }
+
         logger.info("Starting Metric Collector for Apache Cassandra");
 
         // Read Configuration file

pom.xml

@@ -24,7 +24,7 @@
         <mockito.version>3.5.13</mockito.version>
         <prometheus.version>0.16.0</prometheus.version>
         <dropwizard-metrics.version>3.1.5</dropwizard-metrics.version> <!-- This old version is used by Cassandra 4.x -->
-        <jackson-dataformat.version>2.14.0</jackson-dataformat.version>
+        <jackson-dataformat.version>2.13.2</jackson-dataformat.version>
     </properties>
 
     <dependencies>