Fix ClickHouse tracing when database name not included in connection string (#11852)

Author: jaydeluca

instrumentation/clickhouse-client-0.5/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/clickhouse/ClickHouseClientInstrumentation.java

@@ -15,6 +15,7 @@
 
 import com.clickhouse.client.ClickHouseClient;
 import com.clickhouse.client.ClickHouseRequest;
+import com.clickhouse.client.config.ClickHouseDefaults;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
 import io.opentelemetry.javaagent.bootstrap.CallDepth;
@@ -63,7 +64,10 @@ public static void onEnter(
           ClickHouseDbRequest.create(
               clickHouseRequest.getServer().getHost(),
               clickHouseRequest.getServer().getPort(),
-              clickHouseRequest.getServer().getDatabase().get(),
+              clickHouseRequest
+                  .getServer()
+                  .getDatabase()
+                  .orElse(ClickHouseDefaults.DATABASE.getDefaultValue().toString()),
               clickHouseRequest.getPreparedQuery().getOriginalQuery());
 
       if (!instrumenter().shouldStart(parentContext, request)) {

instrumentation/clickhouse-client-0.5/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/clickhouse/ClickHouseClientTest.java

@@ -81,6 +81,31 @@ void cleanup() {
     clickhouseServer.stop();
   }
 
+  @Test
+  void testConnectionStringWithoutDatabaseSpecifiedStillGeneratesSpans()
+      throws ClickHouseException {
+    ClickHouseNode server = ClickHouseNode.of("http://" + host + ":" + port + "?compress=0");
+    ClickHouseClient client = ClickHouseClient.builder().build();
+
+    ClickHouseResponse response =
+        client
+            .read(server)
+            .format(ClickHouseFormat.RowBinaryWithNamesAndTypes)
+            .query("select * from " + tableName)
+            .executeAndWait();
+    response.close();
+
+    testing.waitAndAssertTraces(
+        trace ->
+            trace.hasSpansSatisfyingExactly(
+                span ->
+                    span.hasName("SELECT " + dbName)
+                        .hasKind(SpanKind.CLIENT)
+                        .hasNoParent()
+                        .hasAttributesSatisfyingExactly(
+                            attributeAssertions("select * from " + tableName, "SELECT"))));
+  }
+
   @Test
   void testExecuteAndWaitWithStringQuery() throws ClickHouseException {
     testing.runWithSpan(