make optional /backup/kill query parameter command and optional a…

…rguments for `kill` command handled via `/backup/actions`, if omitted then will kill first command in "In progress" status, fix #808

ChangeLog.md

@@ -1,6 +1,7 @@
 # v2.4.18
 BUG FIXES
-- remove HeadObject request to calculate source key size in CopyObject, to allow cross region S3 disks backup, fix https://github.com/Altinity/clickhouse-backup/issues/813
+- remove HeadObject request to calculate source key size in CopyObject, to allow cross region S3 disks backup, fix [813](https://github.com/Altinity/clickhouse-backup/issues/813)
+- make optional `/backup/kill` query parameter `command` and optional arguments for `kill` command handled via `/backup/actions`, if omitted then will kill first command in "In progress" status, fix [808](https://github.com/Altinity/clickhouse-backup/issues/808) 
 
 # v2.4.17
 BUG FIXES

ReadMe.md

@@ -640,7 +640,7 @@ Restart HTTP server, close all current connections, close listen socket, open li
 
 Kill selected command from `GET /backup/actions` command list, kill process should be near immediate, but some go-routines (upload one data part) could continue to run.
 
-- Optional query argument `command` may contain the command name to kill, or if it is omitted then kill the last "in progress" command.
+- Optional query argument `command` may contain the command name to kill, or if it is omitted then kill the first "in progress" command.
 
 > **GET /backup/tables**
 

pkg/server/server.go

@@ -430,10 +430,10 @@ func (api *APIServer) actionsAsyncCommandsHandler(command string, args []string,
 }
 
 func (api *APIServer) actionsKillHandler(row status.ActionRow, args []string, actionsResults []actionsResultsRow) ([]actionsResultsRow, error) {
-	if len(args) <= 1 {
-		return actionsResults, errors.New("kill <command> parameter empty")
+	killCommand := ""
+	if len(args) > 1 {
+		killCommand = args[1]
 	}
-	killCommand := args[1]
 	commandId, _ := status.Current.Start(row.Command)
 	err := status.Current.Cancel(killCommand, fmt.Errorf("canceled from API /backup/actions"))
 	defer status.Current.Stop(commandId, err)
@@ -622,7 +622,7 @@ func (api *APIServer) httpKillHandler(w http.ResponseWriter, r *http.Request) {
 	if exists && len(command) > 0 {
 		err = status.Current.Cancel(command[0], fmt.Errorf("canceled from API /backup/kill"))
 	} else {
-		err = fmt.Errorf("require non empty `command` parameter")
+		err = status.Current.Cancel("", fmt.Errorf("canceled from API /backup/kill"))
 	}
 	if err != nil {
 		api.sendJSONEachRow(w, http.StatusInternalServerError, struct {