- html - 出于某种原因,IE8 对我的 Sass 文件中继承的 html5 CSS 不友好?
- JMeter 在响应断言中使用 span 标签的问题
- html - 在 :hover and :active? 上具有不同效果的 CSS 动画
- html - 相对于居中的 html 内容固定的 CSS 重复背景?
tl;博士
如何序列化 Flask 应用程序或请求上下文,或该上下文的子集(即可以成功序列化的任何内容),以便我可以从另一个进程而不是线程访问该上下文?
长版
我有一些需要访问 Flask 请求上下文或 App 上下文的函数,我想在后台运行这些函数。
Flask 有一个内置的 @copy_current_request_context
装饰器将函数包装在请求上下文的副本中,以便您可以在不同的线程中运行它:
from threading import Thread
from flask import Flask, request, copy_current_request_context
app = Flask(__name__)
@app.route('/')
def index():
request.foo = 'bar'
@copy_current_request_context
def baz():
print(request.foo)
thr = Thread(target=baz)
thr.start()
return 'ok'
concurrent.futures.ProcessPoolExecutor
使用的内容.不幸的是,由于应用程序上下文中存在线程锁对象,Pickle 失败了:
>>> with app.test_request_context('/'):
... pickle.dumps(appctx)
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
TypeError: can't pickle _thread.lock objects
>>> with app.test_request_context('/'):
... bar = copy_current_request_context(pow)
... pickle.dumps(bar)
...
Traceback (most recent call last):
File "<stdin>", line 3, in <module>
_pickle.PicklingError: Can't pickle <function pow at 0x110bee8c8>: it's not the same object as builtins.pow
dill
.它通过了上述两个测试,但它无法序列化可能最终出现在上下文中的许多其他事物。应用程序上下文特别容易将扩展链接到:SQLAlchemy 就是一个很好的例子。当您使用 SQLAlchemy 并尝试序列化您的应用程序上下文时,会发生以下情况:
>>> from flask_sqlalchemy import SQLAlchemy
>>> db = SQLAlchemy(app)
>>> with app.test_request_context('/'):
... from flask.globals import _app_ctx_stack
... appctx = _app_ctx_stack.top
... dill.dumps(appctx)
...
Traceback (most recent call last):
File "<stdin>", line 4, in <module>
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 294, in dumps
dump(obj, file, protocol, byref, fmode, recurse)#, strictio)
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 287, in dump
pik.dump(obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 437, in dump
self.save(obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 549, in save
self.save_reduce(obj=obj, *rv)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 662, in save_reduce
save(state)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 902, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 856, in save_dict
self._batch_setitems(obj.items())
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 882, in _batch_setitems
save(v)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 549, in save
self.save_reduce(obj=obj, *rv)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 662, in save_reduce
save(state)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 902, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 856, in save_dict
self._batch_setitems(obj.items())
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 882, in _batch_setitems
save(v)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 816, in save_list
self._batch_appends(obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 843, in _batch_appends
save(tmp[0])
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 1386, in save_function
obj.__dict__), obj=obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 638, in save_reduce
save(args)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 786, in save_tuple
save(element)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 771, in save_tuple
save(element)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 1129, in save_cell
pickler.save_reduce(_create_cell, (f,), obj=obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 638, in save_reduce
save(args)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 771, in save_tuple
save(element)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 549, in save
self.save_reduce(obj=obj, *rv)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 662, in save_reduce
save(state)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 902, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 856, in save_dict
self._batch_setitems(obj.items())
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 882, in _batch_setitems
save(v)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 549, in save
self.save_reduce(obj=obj, *rv)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 662, in save_reduce
save(state)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 902, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 856, in save_dict
self._batch_setitems(obj.items())
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 882, in _batch_setitems
save(v)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 549, in save
self.save_reduce(obj=obj, *rv)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 662, in save_reduce
save(state)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 902, in save_module_dict
StockPickler.save_dict(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 856, in save_dict
self._batch_setitems(obj.items())
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 882, in _batch_setitems
save(v)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 504, in save
f(self, obj) # Call unbound method with explicit self
File "/Users/dchevell/Development/python3/sandbox/env/lib/python3.7/site-packages/dill/_dill.py", line 1330, in save_type
StockPickler.save_global(pickler, obj)
File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/pickle.py", line 957, in save_global
(obj, module_name, name)) from None
_pickle.PicklingError: Can't pickle <class 'sqlalchemy.orm.session.SignallingSession'>: it's not found as sqlalchemy.orm.session.SignallingSession
ProcessPoolExecutor
来完成这项工作然而,进程是一个长期存在的池。我唯一的想法是以某种方式强制工作进程在每个任务结束时关闭,但我很确定这只会导致池损坏。
最佳答案
不确定这是否适合您,但有可能使用来自其他进程的 Flask 应用程序上下文。它要求您使用 application factory模式。
# your_project/app.py
def create_app(config_file):
# Load the config file somehow
# Create your app instance
app = Flask(__name__)
# Initialize your extensions
db.init_app(app)
# Mount routes, etc
app.register_blueprint(...)
# Return your app
return app
# your_project/wsgi.py
from .app import create_app
app = create_app("./config/local.cfg")
您定义了一个应用程序工厂并使用它来创建您的应用程序作为
wsgi.py
中的入口点或其他方便的位置,您稍后可以从将在另一个进程中运行的后台脚本访问此应用程序实例。
# your_project/background_script.py
from .wsgi import app
with app.app_context():
# Do some stuff
顺便说一句,这也是将 Flask 与 Celery 一起使用的一种方式,例如,如
in this question 所述.
关于python - 将 flask 请求/应用程序上下文复制到另一个进程,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56143437/
我是 Linux 的新手,并且继承了保持我们的单一 Linux 服务器运行的职责。这是我们的SVN服务器,所以比较重要。 原来在我之前维护它的人有一个 cron 任务,当有太多 svnserve 进程
Node 虽然自身存在多个线程,但是运行在 v8 上的 JavaScript 是单线程的。Node 的 child_process 模块用于创建子进程,我们可以通过子进程充分利用 CPU。范例:
Jenkins 有这么多进程处于事件状态是否正常? 我检查了我的设置,我只配置了 2 个“执行者”... htop http://d.pr/i/RZzG+ 最佳答案 您不仅要限制 Master 中的执
我正在尝试在 scala 中运行这样的 bash 命令: cat "example file.txt" | grep abc Scala 有一个特殊的流程管道语法,所以这是我的第一个方法: val f
很难说出这里要问什么。这个问题模棱两可、含糊不清、不完整、过于宽泛或夸夸其谈,无法以目前的形式得到合理的回答。如需帮助澄清此问题以便重新打开,visit the help center . 关闭 1
我需要一些帮助来理解并发编程的基础知识。事实上,我读得越多,就越感到困惑。因此,我理解进程是顺序执行的程序的一个实例,并且它可以由一个或多个线程组成。在单核CPU中,一次只能执行一个线程,而在多核CP
我的问题是在上一次集成测试后服务器进程没有关闭。 在integration.rs中,我有: lazy_static! { static ref SERVER: Arc> = {
我正在使用 Scala scala.sys.process图书馆。 我知道我可以用 ! 捕获退出代码和输出 !!但是如果我想同时捕获两者呢? 我看过这个答案 https://stackoverflow
我正在开发一个C++类(MyClass.cpp),将其编译为动态共享库(MyClass.so)。 同一台Linux计算机上运行的两个不同应用程序将使用此共享库。 它们是两个不同的应用程序。它不是多线程
我在我的 C 程序中使用 recvfrom() 从多个客户端接收 UDP 数据包,这些客户端可以使用自定义用户名登录。一旦他们登录,我希望他们的用户名与唯一的客户端进程配对,这样服务器就可以通过数据包
如何更改程序,以便函数 function_delayed_1 和 function_delayed_2 仅同时执行一次: int main(int argc, char *argv[]) {
考虑这两个程序: //in #define MAX 50 int main(int argc, char* argv[]) { int *count; int fd=shm
请告诉我如何一次打开三个终端,这样我的项目就可以轻松执行,而不必打开三个终端三次然后运行三个exe文件。请问我们如何通过脚本来做到这一点,即打开三个终端并执行三个 exe 文件。 最佳答案 在后台运行
我编写了一个监控服务来跟踪一组进程,并在服务行为异常、内存使用率高、超出 CPU 运行时间等时发出通知。 这在我的本地计算机上运行良好,但我需要它指向远程机器并获取这些机器上的进程信息。 我的方法,在
关闭。这个问题不符合Stack Overflow guidelines .它目前不接受答案。 想改进这个问题?将问题更新为 on-topic对于堆栈溢出。 8年前关闭。 Improve this qu
我有一个允许用户上传文件的应用程序。上传完成后,必须在服务器上完成许多处理步骤(解压、存储、验证等...),因此稍后会在一切完成后通过电子邮件通知用户。 我见过很多示例,其中 System.Compo
这个问题对很多人来说可能听起来很愚蠢,但我想对这个话题有一个清晰的理解。例如:当我们在 linux(ubuntu, x86) 上构建一个 C 程序时,它会在成功编译和链接过程后生成 a.out。 a.
ps -eaf | grep java 命令在这里不是识别进程是否是 java 进程的解决方案,因为执行此命令后我的许多 java 进程未在输出中列出。 最佳答案 简答(希望有人写一个更全面的): 获
我有几个与内核态和用户态的 Windows 进程相关的问题。 如果我有一个 hello world 应用程序和一个暴露新系统调用 foo() 的 hello world 驱动程序,我很好奇在内核模式下
我找不到很多关于 Windows 中不受信任的完整性级别的信息,对此有一些疑问: 是否有不受信任的完整性级别进程可以创建命名对象的地方? (互斥锁、事件等) 不受信任的完整性级别进程是否应该能够打开一
我是一名优秀的程序员,十分优秀!