[client-v2] Request cancellation

CHANGELOG.md

@@ -27,8 +27,14 @@
 
 - **[client-v2]** `Client.Builder#useBearerTokenAuth(String)` now stores the bearer token under the `access_token` configuration key (with the `Bearer ` prefix) instead of writing it directly into `http_header_authorization`. The HTTP wire format is unchanged, but the token is no longer observable through `Client#getReadOnlyConfig()` under the `http_header_authorization` key.
 
+- **[client-v2]** HTTP `503 Service Unavailable` responses are now surfaced as a connection-style failure (`java.net.ConnectException`) and are retried by default. Previously a `503` was treated as a server error (`ServerException`) and fell under the `ServerRetryable` fault cause. It has been moved to the `ConnectTimeout` fault cause category so that connectivity/availability failures are handled uniformly with other connection errors. Callers that specifically excluded `ServerRetryable` to avoid retrying `503` should now adjust their `client_retry_on_failures` configuration to exclude `ConnectTimeout` instead.
+
+- **[client-v2]** Unexpected/unknown HTTP status codes (those the client cannot interpret as a ClickHouse response) now throw a `ClientException` instead of a `ServerException`. Since the client cannot meaningfully handle these responses, they are reported as a client-side error rather than being attributed to the server.
+
 ### New Features
 
+- **[client-v2]** Added `Client#cancelTransportRequest(String queryId)` to cancel an in-flight request that has not yet received a response from the server, identified by the query id supplied in the operation settings. This aborts the request on the client side (cancels the underlying IO operation) but does **not** issue a `KILL QUERY` on the server, so a query that already started executing may continue to run server-side. It is recommended to use operation timeout settings where possible; this API is intended for explicitly aborting a request from the client.
+
 - **[client-v2]** Added `Session` API to encapsulate and manage ClickHouse session settings (`session_id`, `session_check`, `session_timeout`, `session_timezone`) as a reusable object. The `Session` instance can be applied to any request settings using `applyTo()`, and session state can be cleared via `clearSession()`. Additionally, added `resetOption(String)` to `InsertSettings`, `QuerySettings`, and `CommonSettings` to allow removing specific settings. Settings explicitly set to `null` will not be sent to the server, which is useful for overriding global settings.
 
 - **[client-v2]** Added runtime credential update APIs on `Client`: `updateUserAndPassword(String, String)`, `updateAccessToken(String)`, and `updateBearerToken(String)`. Subsequent requests on the same `Client` instance use the new credentials without rebuilding the client. The authentication method is fixed at construction time; calling a runtime updater that does not match the configured method throws `ClientMisconfigurationException`. See `docs/authentication.md` for details and migration guidance.

client-v2/src/main/java/com/clickhouse/client/api/insert/InsertResponse.java

@@ -3,21 +3,17 @@
 import com.clickhouse.client.api.http.ClickHouseHttpProto;
 import com.clickhouse.client.api.metrics.OperationMetrics;
 import com.clickhouse.client.api.metrics.ServerMetrics;
+import com.clickhouse.client.api.transport.internal.TransportResponse;
 
-import java.util.Collections;
 import java.util.Map;
 
 public class InsertResponse implements AutoCloseable {
     private OperationMetrics operationMetrics;
     private final Map<String, String> responseHeaders;
 
-    public InsertResponse(OperationMetrics metrics) {
-        this(metrics, Collections.emptyMap());
-    }
-
-    public InsertResponse(OperationMetrics metrics, Map<String, String> responseHeaders) {
+    public InsertResponse(TransportResponse transportResponse, OperationMetrics metrics) {
         this.operationMetrics = metrics;
-        this.responseHeaders = responseHeaders;
+        this.responseHeaders = transportResponse.getHeaders();
     }
 
     @Override

client-v2/src/main/java/com/clickhouse/client/api/internal/ClientUtils.java

@@ -1,5 +1,9 @@
 package com.clickhouse.client.api.internal;
 
+import org.slf4j.Logger;
+
+import java.io.Closeable;
+
 /**
  * Class containing utility methods used across the client.
  */
@@ -14,4 +18,14 @@ public static boolean isNotBlank(String str) {
     public static boolean isBlank(String str) {
         return str == null || str.trim().isEmpty();
     }
+
+    public static void quietClose(Closeable closeable, Logger log) {
+        if (closeable != null) {
+            try {
+                closeable.close();
+            } catch (Exception e) {
+                log.warn("Failed to close object " + closeable, e);
+            }
+        }
+    }
 }