Node.js NodeJS Lambda似乎失败，但报告成功

我看到的是我不完全理解的NodeJS Lambda的行为。首先，我假设我们的代码中至少有一个bug，但我们很难理解的问题是，它如何影响同一个Lambda实例上的子序列调用

我所能理解的最大问题是，在初始失败后，我的下一次调用也将失败，我看到一个错误，似乎表明nodejs已经终止。然后我看到它重新初始化并再次成功地开始处理请求

有几个问题：

好的，我们似乎有一个bug，我想我们可以找到它并在某个时候修复它

后续调用中的NodeJ终止，但调用被视为成功（当然不是）

因为第二次调用被认为是成功的，所以不会重试

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让我试着展示一些细节。首先，这是第二次调用，它确实失败了，NodeJS似乎要终止：

START RequestId: a71447b0-19f8-456c-b163-47e0408bf3a1 Version: $LATEST
2019-10-17T00:26:12.295Z    a71447b0-19f8-456c-b163-47e0408bf3a1    INFO    Assuming lambda role: { ... }lambda',
END RequestId: a71447b0-19f8-456c-b163-47e0408bf3a1
REPORT RequestId: a71447b0-19f8-456c-b163-47e0408bf3a1    Duration: 228.19 ms    Billed Duration: 300 ms    Memory Size: 256 MBMax Memory Used: 158 MB
RequestId: a71447b0-19f8-456c-b163-47e0408bf3a1 Error: Runtime exited with error: exit status 129

也许我误解了最后一行，但在我看来，NodeJS肯定要终止了（用SIGHUP？？）。在此之后，下一次调用将显示X射线日志，就像我们在第一次调用此实例时看到的：

2019-10-17T00:55:30.531Z       undefined       INFO    AWS_XRAY_DAEMON_ADDRESS is set. Configured daemon address to 169.xxx.xxx.xxx.
2019-10-17T00:55:30.536Z       undefined       INFO    AWS_XRAY_CONTEXT_MISSING is set. Configured context missing strategy to LOG_ERROR.
2019-10-17T00:55:30.554Z       undefined       INFO    Subsegment streaming threshold set to: 0

所以它在我的lambda实例上重新启动了NodeJs？这是我们应该看到的吗

如果我在X光等中查找此项，则显示错误，但状态为200：

我认为还值得展示之前的调用，它似乎触发了这一点。这也是成功的，它确实返回了正确的值等，但完成后，我在日志中看到：

2019-10-17T00:55:29.169Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.326Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.328Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.329Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.329Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.330Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.368Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.388Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.408Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.428Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.467Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.468Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.469Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.567Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}
2019-10-17T00:55:29.568Z    3bf23bda-e7fa-4fd7-b373-2258baff2bb8    ERROR   Uncaught Exception  {"errorType":"Error","errorMessage":"premature close","stack":["Error: premature close","    at Duplexify.onclose (/var/task/node_modules/end-of-stream/index.js:47:67)","    at Duplexify.emit (events.js:198:13)","    at Duplexify.EventEmitter.emit (domain.js:448:20)","    at Duplexify._destroy (/var/task/node_modules/duplexify/index.js:199:8)","    at /var/task/node_modules/duplexify/index.js:182:10","    at /var/task/node_modules/async-listener/glue.js:188:31","    at process._tickCallback (internal/process/next_tick.js:61:11)"]}

毫无疑问，这是我们代码中的一个bug。我不清楚这可能是什么，因为这些库不是我们的代码使用的库。事实上，这些似乎被AWS X射线所使用。那么，是不是X射线出现了故障，导致了一些调用失败

我试图理解：

• nodejs是否出现故障并正在重新启动
• 是否有一种方法可以捕获此进程终止，并至少将其视为失败的调用
• 简言之：这里发生了什么？它似乎与我们通常期望在lambda中看到的不匹配

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以下是我们将要尝试的一些我们尝试过但没有帮助的事情：

• 升级了aws sdk和X射线软件包：无更改
• 我们已经添加了异常处理和日志记录，但没有学到任何新的东西，现在我们将继续这条路

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更新：在“正常”情况下，包括记录了多个错误的情况下，我们会执行相同的操作。我们订阅一个物联网主题，发布一条消息，并等待长达5秒钟的响应。这些执行都没有在等待响应时超时（我们最多等待5秒，如果没有收到响应，则返回错误），并且Lambda执行都没有超时。在上述情况下（日志中的请求id a71447b0-19f8-456c-b163-47e0408bf3a1），我们不这样做，因为据我所知，我们的代码没有运行-没有日志表明它运行

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这种情况并不经常发生。在过去的几天里，我看到大约每25人中就有1人被处决。这并没有看到太多的负载，所以我们只进行了大约190次调用（到目前为止有8次调用失败）。

几个月后，我们回来报告这到底是什么，以及如何解决它

不明显的是（但事后看来，可能应该是这样的），其根源是在lambda中使用MQTT.js（作为AWS IOT SDK的一部分）。特别是当lambda未激活时，它有时会断开连接-这是合理的预期。这里发生的是，MQTT.js在断开连接时触发一个事件，该事件可能在不可预知的时间运行

它的长与短是我们需要处理

错误

和

关闭

事件。如果它们没有被处理，那么我们有一个未处理的异常，正如我上面所描述的。解决这个问题非常简单-我们只需处理这些事件并创建一个新的客户端等

我认为我们应该比以前简单得多地解决这个问题——我们并不清楚它与MQTT有关（但一旦我们意识到这是一个问题，解决起来就相对比较快）

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作为补充说明，可能值得指出的是，最新的AWS IoT SDK在底层并不使用MQTTjs。我不知道这样做的动机到底是什么，但我不知道这个问题/答案在未来会有多大用处。你使用的是哪个版本？NodeJs是v10.3如果你的回答是200，但没有定义，我们没有正确地从代码返回。据我所知，我们的代码甚至没有在这个调用上运行我知道。那么你的lambda函数里有什么？