add error handler

Author: wankai123

oap-server/server-query-plugin/traceql-plugin/src/main/antlr4/org/apache/skywalking/oap/query/tempo/grammar/TraceQLLexer.g4

@@ -29,9 +29,10 @@ NIL:         'nil';
 // Scope selectors
 RESOURCE:    'resource';
 SPAN:        'span';
-INTRINSIC:   'intrinsic';
-EVENT:       'event';
-LINK:        'link';
+// Not support yet
+//INTRINSIC:   'intrinsic';
+//EVENT:       'event';
+//LINK:        'link';
 
 // Operators
 DOT:         '.';
@@ -50,8 +51,9 @@ LT:          '<';
 LTE:         '<=';
 GT:          '>';
 GTE:         '>=';
-RE:          '=~';  // Regex match
-NRE:         '!~';  // Regex not match
+// Not support yet
+//RE:          '=~';  // Regex match
+//NRE:         '!~';  // Regex not match
 
 // Arithmetic operators
 PLUS:        '+';

oap-server/server-query-plugin/traceql-plugin/src/main/java/org/apache/skywalking/oap/query/traceql/entity/ErrorResponse.java

@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.query.traceql.entity;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import lombok.Builder;
+import lombok.Data;
+
+/**
+ * Error response entity for Tempo API.
+ * Used when requests fail with 4xx or 5xx status codes.
+ */
+@Data
+@Builder
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class ErrorResponse {
+    /**
+     * Error message describing what went wrong.
+     */
+    private String error;
+
+    /**
+     * Optional error code for programmatic error handling.
+     */
+    private String errorType;
+}
+

oap-server/server-query-plugin/traceql-plugin/src/main/java/org/apache/skywalking/oap/query/traceql/exception/IllegalExpressionException.java

@@ -0,0 +1,25 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.apache.skywalking.oap.query.traceql.exception;
+
+public class IllegalExpressionException extends Exception {
+    public IllegalExpressionException(String message) {
+        super(message);
+    }
+}

oap-server/server-query-plugin/traceql-plugin/src/main/java/org/apache/skywalking/oap/query/traceql/handler/TraceQLApiHandler.java

@@ -33,11 +33,16 @@
 import java.util.Optional;
 import org.apache.commons.codec.DecoderException;
 import org.apache.skywalking.oap.query.traceql.entity.BuildInfoResponse;
+import org.apache.skywalking.oap.query.traceql.entity.ErrorResponse;
 import org.apache.skywalking.oap.query.traceql.entity.QueryResponse;
 
 /**
  * Handler for Grafana Tempo API endpoints.
  * Implements the Tempo API specification for trace querying and search.
+ *
+ * Error Handling:
+ * - 200 OK: Successful request
+ * - 400 Bad Request: Invalid request parameters (malformed TraceQL query, invalid duration format, etc.)
  */
 public abstract class TraceQLApiHandler {
     private static final ObjectMapper MAPPER = new ObjectMapper();
@@ -318,5 +323,32 @@ protected HttpResponse successResponse(QueryResponse response) throws JsonProces
             HttpData.ofUtf8(MAPPER.writeValueAsString(response))
         );
     }
+
+    /**
+     * Create an error response with appropriate HTTP status code.
+     *
+     * @param status HTTP status code
+     * @param message Error message
+     * @return HTTP response with error details
+     */
+    protected HttpResponse errorResponse(HttpStatus status, String message) throws JsonProcessingException {
+        ErrorResponse error = ErrorResponse.builder()
+            .error(message)
+            .build();
+        return HttpResponse.of(
+            ResponseHeaders.builder(status)
+                           .contentType(MediaType.JSON)
+                           .build(),
+            HttpData.ofUtf8(MAPPER.writeValueAsString(error))
+        );
+    }
+
+    /**
+     * Create a 400 Bad Request error response.
+     * Used for invalid request parameters like malformed TraceQL queries.
+     */
+    protected HttpResponse badRequestResponse(String message) throws JsonProcessingException {
+        return errorResponse(HttpStatus.BAD_REQUEST, message);
+    }
 }