[kafka_admin_groups] fix delete-offset, add set-offset (#4)

- fix `delete-offset` that not call correct api
- add `set-offset` to allow agents commit offset manually

Author: freeznet

pkg/mcp/kafka_admin_groups_tools.go

@@ -36,15 +36,16 @@ func KafkaAdminAddGroupsTools(s *server.MCPServer, readOnly bool, features []str
 	}
 
 	resourceDesc := "Resource to operate on. Available resources:\n" +
-		"- group: A single Kafka Consumer Group for operations on individual groups (describe, remove-members)\n" +
+		"- group: A single Kafka Consumer Group for operations on individual groups (describe, remove-members, set-offset, delete-offset)\n" +
 		"- groups: Collection of Kafka Consumer Groups for bulk operations (list)"
 
 	operationDesc := "Operation to perform. Available operations:\n" +
 		"- list: List all Kafka Consumer Groups in the cluster\n" +
 		"- describe: Get detailed information about a specific Consumer Group, including members, offsets, and lag\n" +
 		"- remove-members: Remove specific members from a Consumer Group to force rebalancing or troubleshoot issues\n" +
 		"- offsets: Get offsets for a specific consumer group\n" +
-		"- delete-offset: Delete a specific offset for a consumer group of a topic"
+		"- delete-offset: Delete a specific offset for a consumer group of a topic\n" +
+		"- set-offset: Set a specific offset for a consumer group's topic-partition"
 
 	toolDesc := "Unified tool for managing Apache Kafka Consumer Groups.\n" +
 		"This tool provides access to Kafka consumer group operations including listing, describing, and managing group membership.\n" +
@@ -75,6 +76,13 @@ func KafkaAdminAddGroupsTools(s *server.MCPServer, readOnly bool, features []str
 		"   operation: \"delete-offset\"\n" +
 		"   group: \"my-consumer-group\"\n" +
 		"   topic: \"my-topic\"\n\n" +
+		"6. Set a specific offset for a consumer group's topic-partition:\n" +
+		"   resource: \"group\"\n" +
+		"   operation: \"set-offset\"\n" +
+		"   group: \"my-consumer-group\"\n" +
+		"   topic: \"my-topic\"\n" +
+		"   partition: 0\n" +
+		"   offset: 1000\n\n" +
 
 		"This tool requires Kafka super-user permissions."
 
@@ -101,6 +109,14 @@ func KafkaAdminAddGroupsTools(s *server.MCPServer, readOnly bool, features []str
 			mcp.Description("The name of the Kafka topic to operate on. "+
 				"Required for the 'delete' operation. "+
 				"Must be an existing topic name in the Kafka cluster.")),
+		mcp.WithString("partition",
+			mcp.Description("The partition number to set offset for. "+
+				"Required for the 'set-offset' operation. "+
+				"Must be a valid partition number for the specified topic.")),
+		mcp.WithNumber("offset",
+			mcp.Description("The offset value to set. "+
+				"Required for the 'set-offset' operation. "+
+				"Use -1 for earliest offset, -2 for latest offset, or a specific positive value.")),
 	)
 
 	s.AddTool(kafkaGroupsTool, handleKafkaGroupsTool(readOnly))
@@ -146,6 +162,8 @@ func handleKafkaGroupsTool(readOnly bool) func(context.Context, mcp.CallToolRequ
 				return handleKafkaGroupOffsets(ctx, admin, request)
 			case "delete-offset":
 				return handleKafkaGroupDeleteOffset(ctx, admin, request)
+			case "set-offset":
+				return handleKafkaGroupSetOffset(ctx, admin, request)
 			default:
 				return mcp.NewToolResultError(fmt.Sprintf("Invalid operation for resource 'group': %s", operation)), nil
 			}
@@ -249,12 +267,70 @@ func handleKafkaGroupDeleteOffset(ctx context.Context, admin *kadm.Client, reque
 		return mcp.NewToolResultError(fmt.Sprintf("Failed to get topic name: %v", err)), nil
 	}
 
-	response, err := admin.FetchOffsetsForTopics(ctx, groupName, topic)
+	// Create a TopicsSet with the specified topic
+	// This will target all partitions for the given topic
+	topicsSet := make(kadm.TopicsSet)
+	topicsSet.Add(topic)
+
+	// Call DeleteOffsets to delete the offsets for the specified topic
+	responses, err := admin.DeleteOffsets(ctx, groupName, topicsSet)
 	if err != nil {
 		return mcp.NewToolResultError(fmt.Sprintf("Failed to delete offsets: %v", err)), nil
 	}
 
-	jsonBytes, err := json.Marshal(response)
+	// Check for errors in the response
+	if err := responses.Error(); err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Errors occurred during offset deletion: %v", err)), nil
+	}
+
+	jsonBytes, err := json.Marshal(responses)
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to marshal response: %v", err)), nil
+	}
+
+	return mcp.NewToolResultText(string(jsonBytes)), nil
+}
+
+func handleKafkaGroupSetOffset(ctx context.Context, admin *kadm.Client, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	// Get required parameters
+	groupName, err := requiredParam[string](request.Params.Arguments, "group")
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to get group name: %v", err)), nil
+	}
+
+	topic, err := requiredParam[string](request.Params.Arguments, "topic")
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to get topic name: %v", err)), nil
+	}
+
+	partition, err := requiredParam[float64](request.Params.Arguments, "partition")
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to get partition number: %v", err)), nil
+	}
+	partitionInt := int32(partition)
+
+	offset, err := requiredParam[float64](request.Params.Arguments, "offset")
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to get offset value: %v", err)), nil
+	}
+	offsetInt := int64(offset)
+
+	// Create Offsets object with the specified topic, partition, and offset
+	offsets := make(kadm.Offsets)
+	offsets.AddOffset(topic, partitionInt, offsetInt, -1) // Using -1 for leaderEpoch as it's optional
+
+	// Commit the offsets
+	responses, err := admin.CommitOffsets(ctx, groupName, offsets)
+	if err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Failed to commit offsets: %v", err)), nil
+	}
+
+	// Check for errors in the response
+	if err := responses.Error(); err != nil {
+		return mcp.NewToolResultError(fmt.Sprintf("Errors occurred during offset commit: %v", err)), nil
+	}
+
+	jsonBytes, err := json.Marshal(responses)
 	if err != nil {
 		return mcp.NewToolResultError(fmt.Sprintf("Failed to marshal response: %v", err)), nil
 	}