Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/mikekap/gbatchy

Greenlet-based transparent batching of calls
https://github.com/mikekap/gbatchy

Last synced: 7 days ago
JSON representation

Greenlet-based transparent batching of calls

Awesome Lists containing this project

README

        

gbatchy
=======

[![PyPI version](https://badge.fury.io/py/gbatchy.svg)](http://badge.fury.io/py/gbatchy)
[![Build Status](https://travis-ci.org/mikekap/gbatchy.svg?branch=master)](https://travis-ci.org/mikekap/gbatchy)
[![Coverage Status](https://coveralls.io/repos/mikekap/gbatchy/badge.png?branch=master)](https://coveralls.io/r/mikekap/gbatchy?branch=master)

A small library inspired by batchy, but using gevent greenlets instead of yield to transfer control.

For example:

```python
from gbatchy import spawn, pget, batched, batch_context

@batched()
def batch_fn(arg_list):
print 'In batch function with args:'
results = []
for args, kwargs in arg_list:
print '\t', args[0]
results.append(args[0] + 1)
print 'Batch function done'
return results

@batch_context
def fetcher():
results = pget(batch_fn(i, as_future=True) for i in xrange(3))
print results

@batch_context
def test():
pget(spawn(fetcher) for i in xrange(2))

test()
```
would print
```
In batch function with args:
0
1
2
0
1
2
Batch function done
[1, 2, 3]
[1, 2, 3]
```

Mini docs:
-----------

- `@batch_context`: Ensures that the function is running in a batch context (i.e. all concurrent calls to `@batched` functions will be coalesced)
- `spawn(fn, *args, **kwargs)`: start a new greenlet that will run `fn(*args, **kwargs)`. This creates a batch context or uses the current one.
- `spawn_proxy(fn, *args, **kwargs)`: same as spawn(), but returns a proxy type instead of a greenlet. This should help get rid of .get() around a lot of your code.
- `@batched(accepts_kwargs=True)` and `@class_batched()`: marks this function as a batch function. All batch functions take just one arg: args_list: `[(args, kwargs), ...]` (or `[args, ...]` if `accepts_kwargs=False`)
- `pget(iterable)`: a quick way to `.get()` all the arguments passed.
- `pmap(fn, iterable)`: same as `map(fn, iterable)`, except runs in parallel. Note: keyword arguments to pmap are passed through to fn for each element.
- `pfilter(fn, iterable)`: same as `filter(fn, iterable)` except runs in parallel.
- `Pool(size)`: same as gevent.pool.Pool - a way to limit the maximum concurrent amount of work.
- `iwait(greenlets)`: same as gevent.iwait, but works with batch greenlets. Using gevent.iwait with batch greenlets is strongly discouraged and will lead to mysterious hangs.
- `wait(greenlets, timeout, count)`: same as gevent.wait.
- `immediate(v)`: returns an `AsyncResult`-like object that is immediately ready and `immediate(v).get() is v == True`.
- `immediate_exception(exc)`: same as `immediate`, but raises `exc`.
- `with may_block()`: a low-level primitive when you need to use a gevent-native blocking call between calls to @batched functions (e.g. gevent.queue).
- `transform(pending, fn)`: a somewhat low-level, but performant way to take an `AsyncResult`-like object and run `immediate(fn(pending.get()))`. Note that fn must be pure - it cannot interact with greenlets. Any extra kwargs will be passed to `fn`.