The pick_first policies in core and grpclb previously would call
Subchannel.requestConnection() from data-path. They now will schedule
that call in the sync-context to avoid the warning. They will only
call it for the first pick of each picker, to prevent storming the
sync-context.
This is a revised version of #5503 (62b03fd), which was rolled back in f8d0868. The newer version passes SubchannelStateListener to Subchannel.start() instead of SubchannelCreationArgs, which allows us to remove the Subchannel argument from the listener, which works as a solution for #5676.
LoadBalancers that call the old createSubchannel() will get start() implicitly called with a listener that passes updates to the deprecated LoadBalancer.handleSubchannelState(). Those who call the new createSubchannel() will have to call start() explicitly.
GRPCLB code is still using the old API, because it's a pain to migrate the SubchannelPool to the new API. Since CachedSubchannelHelper is on the way, it's easier to switch to it when it's ready. Keeping
GRPCLB with the old API would also confirm the backward compatibility.
Contrary to #5736, we will still keep the sync-context requirement of
requestConnection(), because it prevents API fragmentation.
PickFirstLoadBalancer is the only known violator. We will fix it on
master, but we don't want to make that change on 1.21.x because the
release is soon. We simply remove the warning in this release so that
users won't be annoyed.
This supersedes #5736
We will require Subchannel.requestConnection() to be called from
sync-context (#5722), but SubchannelPicker.requestConnection() is
currently calling it with the assumption of thread-safety. Actually
SubchannelPicker.requestConnection() is called already from
sync-context by ChannelImpl, it makes more sense to move this method
to LoadBalancer where all other methods are sync-context'ed, rather than
making SubchannelPicker.requestConnection() sync-context'ed and fragmenting
the SubchannelPicker API because pickSubchannel() is thread-safe.
C++ also has the requestConnection() equivalent on their LoadBalancer
interface.
I see more cases of wrapping Helper and Subchannel during the work of
XdsLoadBalancer, we will require that all methods that involve mutable
state to be called from the Synchronization Context. We will start
logging warnings first, and make them throw in a future release.
Helper.createSubchannel() is already doing so. This change adds
warnings to the other eligible methods.
https://github.com/grpc/grpc-java/issues/5015
This follows the sort of changes we've done in the past, where the '2'
implies "version 2." We can end up reclaiming the original name if we
wish in the future.
The main reason for this change is to avoid changing to Observer since
the rest of io.grpc consistently uses Listener.
Having two Helpers (the other being LoadBalancer.Helper) is proven to
be confusing, and the one in NameResolver is fundamentally different
from the one from LoadBalancer, as the latter mutates the states while
the former doesn't. Renaming it to Args make it less awkward to
expose it to LoadBalancer, which is needed for creating NameResolvers
for per-locality routing in the XdsLoadBalancer.
As we are now endorsing the wrapping of ClientStreamTracers by
providing ForwardingClientStreamTracer, there is a need for altering
StreamInfo, especially CallOptions before it's passed onto the
delegate. A Builder class and a toBuilder() provides a robust way
to copy the rest of the fields.
This is a breaking change for anybody who creates StreamInfo, which is
unlikely in non-test code, because StreamInfo was added as late as
1.20.0.
* api: fix bugs of missing out customOptions in CreateSubchannelArgs toBuider, hashCode, equals
* trash equals/hashCode for CreateSubchannelArgs as they are problematic
NameResolverRegistry takes on all the logic previously in
NameResolverProvider. But it also allows manual registration of
NameResolvers, which is useful when the providers have complex
construction or need objects injected into them.
This also avoids a circular dependency during class loading since
previously loading any Provider searched for all Providers via
ClassLoader since ClassLoader handling was static within the parent
class.
Fixes#5562
io.grpc has fewer dependencies than io.grpc.internal. Moving it to a
separate artifact lets users use the API without bringing in the deps.
If the library has an optional dependency on grpc, that can be quite
convenient.
We now version-pin both grpc-api and grpc-core, since both contain
internal APIs.
I had to change a few tests in grpc-api to avoid FakeClock. Moving
FakeClock to grpc-api was difficult because it uses
io.grpc.internal.TimeProvider, which can't be moved since it is a
production class. Having grpc-api's tests depend on grpc-core's test
classes would be weird and cause a circular dependincy. Having
grpc-api's tests depend on grpc-core is likely possible, but weird and
fairly unnecessary at this point. So instead I rewrote the tests to
avoid FakeClock.
Fixes#1447
Eric Anderson
Kun Zhang
ZHANG Dapeng
Chengyuan Zhang
Carl Mastrangelo
Jean de Klerk