feat: enforce durable queue resource limits and backpressure

sdk/go/tasks.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"time"
 )
 
 // APIError 提供可分支处理的错误码和请求追踪标识，不包含内部数据库错误。
@@ -18,6 +19,8 @@ type APIError struct {
 	Code       string
 	Message    string
 	RequestID  string
+	// RetryAfter 服务端建议的最小退避时间；缺失、无效或超过一小时返回零，SDK 不自动重试。
+	RetryAfter time.Duration
 }
 
 func (e *APIError) Error() string {
@@ -56,7 +59,7 @@ func (c *Client) ListTasks(ctx context.Context, in ListTasksRequest) (TaskPage,
 	return out, err
 }
 
-// CancelTask 当前只取消 WAITING 状态且不归属流程的任务；重复请求使用原键与原版本。
+// CancelTask 保存取消意图；运行中等待结果确认，重复请求保留原键与原版本。
 func (c *Client) CancelTask(ctx context.Context, id, key string, in CancelTaskRequest) (CancelTaskResult, error) {
 	var out CancelTaskResult
 	if !validID(id) {
@@ -150,7 +153,11 @@ func (c *Client) call(ctx context.Context, method, path, key string, in, out any
 	decoded := json.Unmarshal(raw, &envelope)
 	if response.StatusCode < 200 || response.StatusCode >= 300 {
 		if decoded == nil && envelope.Error != nil && len(envelope.Error.Code) <= 64 && len(envelope.Error.Message) <= 1024 && validID(envelope.RequestID) {
-			return &APIError{response.StatusCode, envelope.Error.Code, envelope.Error.Message, envelope.RequestID}
+			var retryAfter time.Duration
+			if seconds, err := strconv.ParseUint(response.Header.Get("Retry-After"), 10, 32); err == nil && seconds > 0 && seconds <= 3600 {
+				retryAfter = time.Duration(seconds) * time.Second
+			}
+			return &APIError{StatusCode: response.StatusCode, Code: envelope.Error.Code, Message: envelope.Error.Message, RequestID: envelope.RequestID, RetryAfter: retryAfter}
 		}
 		return &HTTPError{StatusCode: response.StatusCode}
 	}
@@ -159,3 +166,13 @@ func (c *Client) call(ctx context.Context, method, path, key string, in, out any
 	}
 	return json.Unmarshal(envelope.Data, out)
 }
+
+// ConfigureQueue 完整替换队列控制参数；重复请求保留原版本及幂等键。
+func (c *Client) ConfigureQueue(ctx context.Context, id, key string, in ConfigureQueueRequest) (CreateQueueResult, error) {
+	var out CreateQueueResult
+	if !validID(id) {
+		return out, errors.New("invalid queue id")
+	}
+	err := c.call(ctx, "POST", "/v1/queues/"+id+":configure", key, in, &out)
+	return out, err
+}