Django
官网有形容
Django异步的变动
- 4.2相比于4.0的变动就是应用sync_to_async
- 最大的变动就是能够应用同步和异步互不影响
异步实现
models文件夹下的query文件
class BaseIterable: def __init__( self, queryset, chunked_fetch=False, chunk_size=GET_ITERATOR_CHUNK_SIZE ): self.queryset = queryset self.chunked_fetch = chunked_fetch self.chunk_size = chunk_size async def _async_generator(self): # Generators don't actually start running until the first time you call # next() on them, so make the generator object in the async thread and # then repeatedly dispatch to it in a sync thread. sync_generator = self.__iter__() def next_slice(gen): return list(islice(gen, self.chunk_size)) while True: chunk = await sync_to_async(next_slice)(sync_generator) for item in chunk: yield item if len(chunk) < self.chunk_size: break # __aiter__() is a *synchronous* method that has to then return an # *asynchronous* iterator/generator. Thus, nest an async generator inside # it. # This is a generic iterable converter for now, and is going to suffer a # performance penalty on large sets of items due to the cost of crossing # over the sync barrier for each chunk. Custom __aiter__() methods should # be added to each Iterable subclass, but that needs some work in the # Compiler first. def __aiter__(self): return self._async_generator()class ModelIterable(BaseIterable): """Iterable that yields a model instance for each row.""" def __iter__(self): 代码省略class QuerySet(AltersData): """Represent a lazy database lookup for a set of objects.""" def __init__(self, model=None, query=None, using=None, hints=None): self._iterable_class = ModelIterable def __aiter__(self): # Remember, __aiter__ itself is synchronous, it's the thing it returns # that is async! async def generator(): await sync_to_async(self._fetch_all)() for item in self._result_cache: yield item return generator()论断
- 就是__aiter__ 实现了async for 办法，具体的await obj是通过sync_to_async实现
- 感觉ORM层面的异步和同步区别不大，毕竟在数据连贯层面没有变动
- 临时看进去的就这么多，技术无限，后续持续跟进