• Kirill Smelkov's avatar
    sync.WorkGroup: Provide "with" support · 6eb80104
    Kirill Smelkov authored
    So that it becomes possible to write
    
        with WorkGroup(ctx) as wg:
            wg.go(f1)
            wg.go(f2)
    
    instead of
    
        wg = WorkGroup(ctx)
        defer(wg.wait)
        wg.go(f1)
        wg.go(f2)
    
    or
    
        wg = WorkGroup(ctx)
        wg.go(f1)
        wg.go(f2)
        wg.wait()
    
    This is sometimes handy and is referred to as "structured concurrency"
    in Python world.
    
    sync.Sema, sync.Mutex, sync.RWMutex already support "with".
    sync.WaitGroup is imho too low-level, but we might consider adding
    "with" support for it in the future as well.
    
    In general pygolang way is to use defer instead of plugging all classes
    with __enter__/__exit__ "with" support, but for small well-known class of
    concurrency-related things its seems "with" support is worth it:
    
    - having "with" for sync.Mutex+co allows it to be used as a drop-in
      replacement instead of threading.Lock+co, and
    - having "with" for sync.WorkGroup - the most commonly-used tool to
      spawn jobs and wait for their completion - makes it on-par with
      "structured concurrency".
    
    /reviewed-on !12
    6eb80104
_sync.pyx 11.5 KB