英文:
Does LRU caching prevent sentry from creating multiple instances?
问题
我正在使用 Sentry 监控我的应用程序。初始化如下:
from functools import lru_cache
import sentry_sdk
@lru_cache
def start_sentry():
sentry_instance = sentry_sdk.init(DSN)
return sentry_instance
现在,如果我多次执行 start_sentry
,实际上所有创建的多个 sentry_instance
都指向内存中的同一个对象。如果不使用 lru_cache
装饰器,会在内存中创建新的 Sentry 实例。所以我的问题是:使用 lru 缓存是否达到了我期望的效果,即尽管我尝试多次执行它,它是否只会初始化 Sentry 一次?
我使用的是 Python 3.6.7 和 sentry-sdk 版本 0.10.2。
英文:
I am using sentry to monitor my application. The initialization is done like thus:
from functools import lru_cache
import sentry_sdk
@lru_cache
def start_sentry():
sentry_instance = sentry_sdk.init(DSN)
return sentry_instance
Now, if i were to execute start_sentry
multiple times, the multiple sentry_instance
s created are actually all pointing to the same object in memory. Without using the lru_cache
decorator, new sentry instances are crated in memory. So my question is: is using lru caching doing what I am expecting, that is - will it only initialize sentry once even though i attempt to do it multiple times?
i am on python3.6.7 sentry-sdk==0.10.2
答案1
得分: 1
只要在相同进程中调用,它会像这样工作。
这是一个很大的假设。根据您的 Web 应用程序,工作进程可能会预先分叉,在这种情况下,缓存无法跨进程工作。
一个重现此情况的最小示例是:
from functools import lru_cache
from multiprocessing import Process
@lru_cache
def start_sentry():
print("starting sentry")
...
return
if __name__ == "__main__":
proc1 = Process(target=start_sentry)
proc1.start()
proc1.join()
proc2 = Process(target=start_sentry)
proc2.start()
proc2.join()
您将会看到在这段代码中会打印两次 "starting sentry",因为每个进程都有自己的缓存,它们无法相互通信。
英文:
It will work like that provided it's called within the same process.
That's a big if. Depending on your web application, workers might be pre-forked, and in this case the cache doesn't work across processes.
A minimal example to reproduce that is:
from functools import lru_cache
from multiprocessing import Process
@lru_cache
def start_sentry():
print("starting sentry")
...
return
if __name__ == "__main__":
proc1 = Process(target=start_sentry)
proc1.start()
proc1.join()
proc2 = Process(target=start_sentry)
proc2.start()
proc2.join()
You will see "starting sentry" printed twice with this code, because each process got its own cache and they have no way of talking to eachother.
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