move original cmd tester to standalone source

pkg/loadtester/task_shell.go

@@ -0,0 +1,52 @@
+package loadtester
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"go.uber.org/zap"
+	"os/exec"
+	"strconv"
+)
+
+const TaskTypeShell = "cmd"
+
+func init() {
+	taskFactories.Store(TaskTypeShell, func(metadata map[string]string, canary string, logger *zap.SugaredLogger) (Task, error) {
+		cmd, ok := metadata["cmd"]
+		if !ok {
+			return nil, errors.New("cmd not found in metadata")
+		}
+		logCmdOutput, _ := strconv.ParseBool(metadata["logCmdOutput"])
+		return &CmdTask{TaskBase{canary, logger}, cmd, logCmdOutput}, nil
+	})
+}
+
+type CmdTask struct {
+	TaskBase
+	command      string
+	logCmdOutput bool
+}
+
+func (task *CmdTask) Hash() string {
+	return hash(task.canary + task.command)
+}
+
+func (task *CmdTask) Run(ctx context.Context) bool {
+	cmd := exec.CommandContext(ctx, "sh", "-c", task.command)
+	out, err := cmd.CombinedOutput()
+
+	if err != nil {
+		task.logger.With("canary", task.canary).Errorf("command failed %s %v %s", task.command, err, out)
+	} else {
+		if task.logCmdOutput {
+			fmt.Printf("%s\n", out)
+		}
+		task.logger.With("canary", task.canary).Infof("command finished %s", task.command)
+	}
+	return err == nil
+}
+
+func (task *CmdTask) String() string {
+	return task.command
+}