[sdk-platform-java] Race condition in TracedUnaryCallable causes flaky integration tests

未關閉
  • 哪裡不對？
#12,657 0 則留言 0 個 reaction 已指派 0 人 在 GitHub 檢視

維護者通常 1 天內回覆

還沒有人認領這個 Issue。

評估

難度
3/5
預估耗時
1-2 天
新手友好度
68/100
Issue 類型
缺陷
描述清晰度
描述清楚
活躍度
冷清
技術堆疊
grpc, java
領域
observability, testing

研究方向

從 TracedUnaryCallable 和 TracedBatchingCallable 開始，然後檢查 issue 中描述的 ApiFutures callback 使用方式。執行 ITOtelGoldenMetrics 以重現空 metrics 失敗。完成的標準是：只有在 TraceFinisher 記錄成功或失敗之後，回傳的 future 才完成，且整合測試不再間歇性失敗。

由索引模型根據 Issue 內容生成。

描述

priority: p3 type: feature request

Description

In gax-java, observability tracers (such as TracedUnaryCallable and TracedBatchingCallable) use TraceFinisher attached via ApiFutures.addCallback to record metrics and spans upon completion.

ApiFutures.addCallback(future, finisher, MoreExecutors.directExecutor());

This pattern creates a race condition in synchronous environments, such as integration tests (ITOtelGoldenMetrics), where the test thread calls future.get() and immediately asserts state (e.g., checks OpenTelemetry metrics).

Root Cause

When the underlying RPC future completes, the Guava/ApiFuture infrastructure notifies listeners. addCallback attaches a listener that runs independently of the future's resolution state for the blocking caller.

In ITOtelGoldenMetrics:

  1. client.echo() blocks the test thread.
  2. The gRPC network thread completes the RPC.
  3. The test thread unblocks and calls metricReader.collectAllMetrics().
  4. Concurrently (or slightly after), the TraceFinisher runs to record the metric in the OTel meter.

If the test thread executes before the TraceFinisher completes its work, the test fails with "empty metrics".

Proposed Solution

Convert the detached addCallback into a chained future transformation. This guarantees that the returned future only resolves after the tracer has finished recording metrics/spans.

Example for TracedUnaryCallable:

ApiFuture<ResponseT> onSuccessFuture =
    ApiFutures.transform(
        future,
        response -> {
            finisher.onSuccess(response);
            return response;
        },
        MoreExecutors.directExecutor());

return ApiFutures.catchingAsync(
    onSuccessFuture,
    Throwable.class,
    t -> {
        finisher.onFailure(t);
        return ApiFutures.immediateFailedFuture(t);
    },
    MoreExecutors.directExecutor());

This approach ensures structural LIFO ordering: the metric is recorded before any downstream consumer can yield from a blocking .get() on the returned future.

主要語言
Java
星號
2.1k
分支
1.2k
平均合併
2 天 14 小時
30 天內合併 PR
192

環境準備

  • 沒有 Dockerfile 或 Docker Compose 檔案
  • 沒有 Pull Request 範本
  • 閱讀貢獻指南

從這裡開始

  1. 先讀完整個 Issue，再讀專案的貢獻指南。
  2. 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
  3. Fork 儲存庫，在一個分支上完成修改。
  4. 送出 Pull Request，並在描述裡引用這個 Issue 編號。

googleapis/google-cloud-java 的其他 Issue

查看 googleapis/google-cloud-java 的全部 Issue

相似的 Issue

更多 Java Issue

把新 issue 寄到你的電子郵件信箱

精選適合新手參與的 GitHub issue 摘要。