comparison tests/test-batching.py @ 33766:4c706037adef

wireproto: overhaul iterating batcher code (API)

The remote batching code is difficult to read. Let's improve it.

As part of the refactor, the future returned by method calls on
batchiter() instances is now populated. However, you still need to
consume the results() generator for the future to be set.  But at
least now we can stuff the future somewhere and not have to worry
about aligning method call order with result order since you can
use a future to hold the result.

Also as part of the change, we now verify that @batchable generators
yield exactly 2 values. In other words, we enforce their API.

The non-iter batcher has been unused since b6e71f8af5b8. And to my
surprise we had no explicit unit test coverage of it! test-batching.py
has been overhauled to use the iterating batcher.

Since the iterating batcher doesn't allow non-batchable method
calls nor local calls, tests have been updated to reflect reality.
The iterating batcher has been used for multiple releases apparently
without major issue. So this shouldn't cause alarm.

.. api::

   @peer.batchable functions must now yield exactly 2 values

Differential Revision: https://phab.mercurial-scm.org/D319

33765:e2fc2122029c

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import, print_function

from mercurial import (
    peer,
    wireproto,
)

# equivalent of repo.repository
class thing(object):

        return "Nope"
    def bar(self, b, a):
        return "%s und %s" % (b, a,)
    def greet(self, name=None):
        return "Hello, %s" % name
    def batch(self):
        '''Support for local batching.'''
        return peer.localbatch(self)

# usage of "thing" interface
def use(it):

    # Direct call to base method shared between client and server.

    # Direct calls to proxied methods. They cause individual roundtrips.
    print(it.foo("Un", two="Deux"))
    print(it.bar("Eins", "Zwei"))

    # Batched call to a couple of (possibly proxied) methods.
    batch = it.batch()
    # The calls return futures to eventually hold results.
    foo = batch.foo(one="One", two="Two")
    bar = batch.bar("Eins", "Zwei")
    # We can call non-batchable proxy methods, but the break the current batch
    # request and cause additional roundtrips.
    greet = batch.greet(name="John Smith")
    # We can also add local methods into the mix, but they break the batch too.
    hello = batch.hello()
    bar2 = batch.bar(b="Uno", a="Due")
    # Only now are all the calls executed in sequence, with as few roundtrips
    # as possible.
    batch.submit()
    # After the call to submit, the futures actually contain values.
    print(foo.value)
    print(bar.value)
    print(greet.value)
    print(hello.value)
    print(bar2.value)

# local usage
mylocal = localthing()
print()
print("== Local")

        for name, args in cmds:
            args = ','.join(n + '=' + escapearg(v) for n, v in args)
            req.append(name + ':' + args)
        req = ';'.join(req)
        res = self._submitone('batch', [('cmds', req,)])
        return res.split(';')

    def batch(self):
        return wireproto.remotebatch(self)

    @peer.batchable
    def foo(self, one, two=None):
        encargs = [('one', mangle(one),), ('two', mangle(two),)]
        encresref = peer.future()

33766:4c706037adef

# GNU General Public License version 2 or any later version.

from __future__ import absolute_import, print_function

from mercurial import (
    error,
    peer,
    util,
    wireproto,
)

# equivalent of repo.repository
class thing(object):

        return "Nope"
    def bar(self, b, a):
        return "%s und %s" % (b, a,)
    def greet(self, name=None):
        return "Hello, %s" % name
    def batchiter(self):
        '''Support for local batching.'''
        return peer.localiterbatcher(self)

# usage of "thing" interface
def use(it):

    # Direct call to base method shared between client and server.

    # Direct calls to proxied methods. They cause individual roundtrips.
    print(it.foo("Un", two="Deux"))
    print(it.bar("Eins", "Zwei"))

    # Batched call to a couple of proxied methods.
    batch = it.batchiter()
    # The calls return futures to eventually hold results.
    foo = batch.foo(one="One", two="Two")
    bar = batch.bar("Eins", "Zwei")
    bar2 = batch.bar(b="Uno", a="Due")

    # Future shouldn't be set until we submit().
    assert isinstance(foo, peer.future)
    assert not util.safehasattr(foo, 'value')
    assert not util.safehasattr(bar, 'value')
    batch.submit()
    # Call results() to obtain results as a generator.
    results = batch.results()

    # Future results shouldn't be set until we consume a value.
    assert not util.safehasattr(foo, 'value')
    foovalue = next(results)
    assert util.safehasattr(foo, 'value')
    assert foovalue == foo.value
    print(foo.value)
    next(results)
    print(bar.value)
    next(results)
    print(bar2.value)

    # We should be at the end of the results generator.
    try:
        next(results)
    except StopIteration:
        print('proper end of results generator')
    else:
        print('extra emitted element!')

    # Attempting to call a non-batchable method inside a batch fails.
    batch = it.batchiter()
    try:
        batch.greet(name='John Smith')
    except error.ProgrammingError as e:
        print(e)

    # Attempting to call a local method inside a batch fails.
    batch = it.batchiter()
    try:
        batch.hello()
    except error.ProgrammingError as e:
        print(e)

# local usage
mylocal = localthing()
print()
print("== Local")

        for name, args in cmds:
            args = ','.join(n + '=' + escapearg(v) for n, v in args)
            req.append(name + ':' + args)
        req = ';'.join(req)
        res = self._submitone('batch', [('cmds', req,)])
        for r in res.split(';'):
            yield r

    def batchiter(self):
        return wireproto.remoteiterbatcher(self)

    @peer.batchable
    def foo(self, one, two=None):
        encargs = [('one', mangle(one),), ('two', mangle(two),)]
        encresref = peer.future()