Question

在python中，是否有一种机制：

重新加载顶级模块（sys.modules['__main__']）或
只是在运行时更新顶层模块中的函数吗？

假设我们有顶级dsu.py，我们想在运行时通过添加一个函数来修补导入的模块updating.simple，然后通过添加一个main()来修补dsu.py调用添加到updating.simple的函数。最后，我们要重新加载updating.simple以使用已修补的代码，然后重新加载dsu.py以使用信号处理程序中的reload-mechanism调用updating.simple中的新函数。

dsu.py:

import importlib, signal, time, sys
import updating.simple

def update_handler(sig, frame):
    importlib.reload(updating.simple)
    # 1. reload "this" module here or 2. reload only main()

def main():
    while True:
        print("Result : %i" % updating.simple.computation(1,2))
        # patch with: print("Another: %i" % updating.simple.anothercomputation(2,1)) go here
        time.sleep(0.5)

if __name__ == '__main__':
    signal.signal(signal.SIGUSR1, update_handler)
    main()

updating\simple.py:

def computation(a,b):
    return a * b

虽然问题与动态更新（或猴子修补）有关，但我已添加了补丁和测试代码（python3 test.py）以供参考：

https://bitbucket.org/vilvo/py-reload-module-and-dependent/src

预期行为：

$ python3 test.py 
Starting the process: python3.4 ./dsu.py
Result : 2
Updating module with a patch that adds a method
and the added method is called from the main()
patching file updating/simple.py
diff --git a/updating/simple.py b/updating/simple.py
index 6bd6318..6434e5a 100644
--- a/updating/simple.py
+++ b/updating/simple.py
@@ -1,2 +1,5 @@
 def computation(a,b):
     return a * b
+
+def anothercomputation(a,b):
+    return a * b * b * a
patching file ./dsu.py
diff --git a/dsu.py b/dsu.py
index 508f7c6..74d27e3 100644
--- a/dsu.py
+++ b/dsu.py
@@ -8,6 +8,7 @@ def update_handler(sig, frame):

 def main():
     while True:
+        print("Another: %i" % updating.simple.anothercomputation(2,1))
         print("Result : %i" % updating.simple.computation(1,2))
         time.sleep(0.5)

diff --git a/updating/simple.py b/updating/simple.py
index 6bd6318..6434e5a 100644
--- a/updating/simple.py
+++ b/updating/simple.py
@@ -1,2 +1,5 @@
 def computation(a,b):
     return a * b
+
+def anothercomputation(a,b):
+    return a * b * b * a
Trigger dynamic software update with user signal
Another: 4
Result : 2
Reverting patches
Another: 4
Result : 2
Trigger dynamic software update with user signal
Result : 2
Stopping the process with pid 11547
Cleaning files generated by Python
Removing __pycache__/
Removing updating/__pycache__/

我的两个试验可以在git-repository中找到：

$ git log --oneline
7c7c828 Trial on reloading only updated main() and executing it
2fd68d6 Study on dynamic update of a module and dependent with Python

任何洞察力都表示赞赏，我也很好奇是否可以使用框架黑客。

重新加载模块和依赖顶级模块

0 个答案: