Google Cloud Functions执行时间和限制

There are several tips from the best practices that may help you reduce the performance issues:

• Remove unused dependencies

  If your functions import modules, the load time for those modules can add to the invocation latency during a cold start. You can reduce this latency, as well as the time needed to deploy your function, by loading dependencies correctly and not loading dependencies your function doesn't use.

• Use global variables to reuse objects in future invocations

  There is no guarantee that the state of a Cloud Function will be preserved for future invocations. However, Cloud Functions often recycles the execution environment of a previous invocation. If you declare a variable in global scope, its value can be reused in subsequent invocations without having to be recomputed.

• Do lazy initialization of global variables

  If you initialize variables in global scope, the initialization code will always be executed via a cold start invocation, increasing your function's latency. If some objects are not used in all code paths, consider initializing them lazily on demand.

Also regarding the access to Google APIs, as you are fetching messages from PUB/SUB, it's better to create the Pub/Sub client object in global scope. There's more information and a sample code regarding that in the public documentation.

云功能还需要一些时间来扩展，因此，如果请求数量过多，这也可能会导致您遇到的高延迟。一种解决方法是，创建两个订阅您的发布/订阅主题的Cloud Functions，或者为这两个功能创建2个单独的主题，然后将工作量分配到这两个中。