5. 动作 Action
Action 用于 长时任务：Goal、Feedback、Result，支持取消与抢占。对标 ROS 2 Action。
本文 §5 |
相关文档 |
|---|---|
长任务 |
Python Action 示例尚未实现（py_action_server.py 为占位）；以下以 C++ 与 examples.proto 为准。
5.1 调用流程
| 要点 | 说明 |
|---|---|
| Traits | 聚合 Goal / Feedback / Result 三种 protobuf（见下方示例） |
| 与 Service | Service 同步阻塞一轮；Action 异步 + 流式 Feedback |
| 取消 | AsyncCancelGoal → IsCancelRequested → TerminateCurrent |
| 抢占 | 新 Goal → IsPreemptRequested → AcceptPendingGoal |
message SimpleMessageAction {
message Goal { string text = 1; }
message Feedback { int32 index = 1; }
message Result { bool success = 1; }
}
struct SimpleMessageActionTraits {
using Goal = ae::SimpleMessageAction_Goal;
using Feedback = ae::SimpleMessageAction_Feedback;
using Result = ae::SimpleMessageAction_Result;
};
Autonomy 导航 Action 定义见 commsgs Action。
5.2 SimpleActionServer
action_listener.cpp 使用 SimpleActionServer，在 goal 被接受后于 工作线程 执行：
constexpr char kActionName[] = "examples/simple_message_action";
void RunAcceptedGoal(const std::shared_ptr<ActionServer>& server) {
GoalPtr goal = server->GetCurrentGoal();
AINFO << "Executing goal, text=\"" << goal->text() << "\"";
for (int i = 0; i < kFeedbackSteps; ++i) {
if (server->IsCancelRequested()) {
ResultPtr aborted = std::make_shared<Result>();
aborted->set_success(false);
server->TerminateCurrent(aborted);
return;
}
if (server->IsPreemptRequested()) {
server->AcceptPendingGoal(); // 切换至 pending goal
break;
}
FeedbackPtr fb = std::make_shared<Feedback>();
fb->set_index(i);
server->PublishFeedback(fb);
std::this_thread::sleep_for(kFeedbackPeriod);
}
ResultPtr ok = std::make_shared<Result>();
ok->set_success(true);
server->SucceededCurrent(ok);
}
int main(int argc, char* argv[]) {
autolink::Init(argv[0]);
auto node = autolink::CreateNode(node_name);
std::shared_ptr<ActionServer> server;
server = std::make_shared<ActionServer>(
node, kActionName,
[&server]() { RunAcceptedGoal(server); }); // execute 回调
autolink::WaitForShutdown();
}
关键 API：
方法 |
用途 |
|---|---|
|
当前执行中的 goal |
|
推送进度 |
|
客户端请求取消 |
|
新 goal 抢占 |
|
切换到 pending goal |
|
成功结束 |
|
取消 / 异常结束 |
5.3 AsyncSendGoal
action_talker.cpp 演示 Client 侧完整流程：
auto client = autolink::action::CreateClient<SimpleMessageActionTraits>(
node, kActionName);
// 1. 等待 Server 就绪
while (autolink::OK() && !client->ActionServerIsReady()) {
std::this_thread::sleep_for(kWaitServerReady);
}
// 2. 构造 Goal 与回调选项
SimpleMessageActionTraits::Goal goal;
goal.set_text("hello from action_talker");
ActionClient::SendGoalOptions opts;
opts.goal_response_callback = [](std::shared_ptr<GoalHandle> gh) {
if (!gh) AWARN << "Goal rejected by server";
};
opts.feedback_callback = [](auto gh, auto fb) {
if (fb) AINFO << "Feedback index=" << fb->index();
};
// 3. 发送并等待接受
const auto accepted_future = client->AsyncSendGoal(goal, opts);
accepted_future.wait_for(kAcceptTimeout);
std::shared_ptr<GoalHandle> handle = accepted_future.get();
// 4. 等待最终结果
auto result_future = handle->AsyncGetResult();
result_future.wait_for(kResultTimeout);
LogActionOutcome(handle, result_future.get());
GoalHandle::WrappedResult 含终端状态：SUCCEEDED、CANCELED、ABORTED 等，可用 autolink::action::ToString(wr.code) 打印。
5.4 运行示例
export AUTOLINK_PATH=...
cd build/autolink/bin/examples
# terminal 1 — 必须先启 Server
./action_listener
# terminal 2
./action_talker
预期日志：Server 周期 feedback index=0..N，Client 打印 Goal accepted 与 Action terminal: SUCCEEDED。
5.5 集成要点
Execute 在工作线程：
SimpleActionServer的 execute 回调内长循环会阻塞新 goal 接受。Feedback：Server 调用
PublishFeedback；Client 注册feedback_callback。Autonomy：Navigator 以 Action Client 调用 Controller，消息定义见 commsgs。