Debug mechanism

[simonw]

Add a mechanism which shows exactly how the class is executing, including which methods are running in parallel. Maybe even with a very basic ASCII visualization? Then use it to help illustrate the examples in the README, refs #4.

[simonw]

Adding a class property (or instance property) of _debug_asyncinject = True which is then detected by the resolve() method (which gets passed the instance) is a very basic way this could work:

asyncinject/asyncinject/__init__.py

Lines 81 to 84 in 28fb38f

	async def resolve(instance, names, results=None):
	if results is None:
	results = {}

[simonw]

Prototype:

diff --git a/asyncinject/__init__.py b/asyncinject/__init__.py
index 8323b67..bf78932 100644
--- a/asyncinject/__init__.py
+++ b/asyncinject/__init__.py
@@ -50,6 +50,8 @@ def _make_method(method):
 
 
 class AsyncInject:
+    _debug_asyncinject = True
+
     def __init_subclass__(cls, **kwargs):
         super().__init_subclass__(**kwargs)
         # Decorate any items that are 'async def' methods
@@ -82,6 +84,8 @@ async def resolve(instance, names, results=None):
     if results is None:
         results = {}
 
+    debug = getattr(instance, "_debug_asyncinject", False)
+
     # Come up with an execution plan, just for these nodes
     ts = graphlib.TopologicalSorter()
     to_do = set(names)
@@ -101,8 +105,13 @@ async def resolve(instance, names, results=None):
         plan.append(node_group)
         ts.done(*node_group)
 
+    if debug:
+        print("\nResolving {} in {}".format(names, instance))
+
     for node_group in plan:
         awaitable_names = [name for name in node_group if name in instance._registry]
+        if debug:
+            print("  ", awaitable_names)
         awaitables = [
             instance._registry[name](
                 instance,

Running with pytest -s:

 % pytest -s        
...
collected 6 items                                                                                                                                                      

tests/test_asyncinject.py 
Resolving ['two'] in <test_asyncinject.Simple object at 0x106ef88e0>
   ['two']
.
Resolving ['a'] in <test_asyncinject.Complex object at 0x106ef9120>
   ['c', 'd']
   ['b']
   ['a']
.
Resolving ['calc1', 'calc2'] in <test_asyncinject.WithParameters object at 0x106ef9360>
   ['calc2', 'calc1']
.
Resolving ['calc1', 'calc2'] in <test_asyncinject.WithParametersComplex object at 0x106efb880>
   ['calc1']
   ['calc2']
.
Resolving ['calc1'] in <test_asyncinject.IgnoreDefaultParameters object at 0x106efa800>
   ['calc1']
.
Resolving ('calc1', 'calc2') in <test_asyncinject.WithParameters object at 0x106ef9030>
   ['calc2', 'calc1']

[simonw]

Even simpler: _debug starts as a lambda s: None function, but can be replaced with instance._debug = print or anything else.

[simonw]

Documentation: https://github.com/simonw/asyncinject/blob/47348978242880bd72a444158bbecc64566b0c55/README.md#debug-logging