Because otherwise the user logic around Subchannel creation will
likely to race with handleSubchannelState().
Will log a warning if LoadBalancer.Helper.createSubChannel() is called
outside of the SynchronizationContext.
Adds SynchronizationContext.throwIfNotInThisSynchronizationContext()
to facilitate this warning. It can also be used by LoadBalancer
implementations to make it a requirement.
LoadBalancerProvider is the interface that extends LoadBalancer.Factory. LoadBalancerRegistry is the one that loads the providers through service loader, and allows users to access providers through their names.
pick_first and round_robin balancer factories, which are experimental public API are now deprecated. Their providers are internal, as they are accessible by policy name.
AutoConfiguredLoadBalancerFactory is modified to access implementations purely by their names, thus hard-coded class names are no longer needed, and it can support arbitrary policy selected by service config.
The trailing dot denotes the hostname to be absolute. It is fine to
leave, but removing it makes the authority match the more common form
and hopefully reduces confusion.
This happens to works around SNI failures caused when using gRPC-LB,
since SNI prohibits the trailing dot. However, that is not the reason
for this change as we have to support users directly providing a
hostname with the trailing dot anyway (and doing so is not hard).
See #4912
Swapping MetadataApplier to an abstract class is not ABI-safe for
callers. So I revert back to the previous interface definition and
introduce a CallCredentials2.MetadataApplier which is an abstract class.
Once everyone is on CallCredentials2 then we can swap it to an abstract
class again.
Fixes#5002
Previously the client waits ~10 seconds until the fallback timer has
expired. While the timer is useful to address the long tail, it
shouldn't delay using the fallback in case of obvious errors, like the
channel failing to connect or an UNIMPLEMENTED response.
Provides a `SynchronizationContext` for scheduling tasks, with and without delay, from LoadBalancer implementations. This absorbs and extends the internal utility `ChannelExecutor`. It supersedes `Helper.runSerialized()`, which is now deprecated.
# Motivation
I see multiple cases that schedule tasks with a delay while requiring the task to run in the "Channel Executor". There have been repeated work to wrap scheduled tasks and handle races between cancellation and task run (see the diff in `GrpclbState.java` for example). The LoadBalancer implementation (e.g., GrpclbLoadBalancer) also has to acquire the `ScheduledExecutorService` from somewhere and release it upon shutdown.
The upcoming HealthCheckLoadBalancer (#4932), which would use back-off policy to retry health-checking streams, would have to do all the things above. At this point I think we need to provide something that combines `runSerialized()` with a scheduled executor with the same synchronization guarantees.
# Design details
`SynchronizationContext` is a similar to `ScheduledExecutorService` but tailored for use in `LoadBalancer` and potentially other cases outside of `LoadBalancer`. It offers task queuing and serialization and delayed scheduling. It guarantees non-reentrancy and happens-before among tasks. It owns no thread, but run tasks on caller's or caller-provided threads.
All channel-level state mutations and callback methods on `LoadBalancer` are done in a SynchronizationContext, which was previously referred to as "Channel Executor".
`SynchronizationContext.schedule()` returns a `ScheduledHandle` for status checking and cancellation. `ScheduedFuture` from `SchedulingExecutorService.schedule()` is too broad for our use cases (e.g., the blocking `get()` should never be used).
`SynchronizationContext.schedule()` requires a `ScheduledExecutorService`, which is now available through `Helper.getScheduledExecutorService()`. LoadBalancers don't need to worry about where to get `SchedulingExecutorService` any more.
# Alternatives
Alternatively, we could keep `Helper.runSerialized()` and add something like `Helper.runSerialiezdWithDelay()`, but having them on their own interface allows clean fake implementation by `FakeClock` for test, and allows other components (potentially `InternalSubchannel` for reconnection backoff) to use it too.
Instead of asking caller of `schedule()` to provide the `ScheduledExecutorService`, we considered having SynchronizationContext take a `ScheduledExecutorService` at construction. It would be inconvenient for LoadBalancer implementations that don't use `schedule()`, as they would be forced to provide a fake `ScheduledExecutorService` (which is cumbersome).
Instead of making `SynchronizationContext` a (semi-)concrete class, we considered making it an pure abstract class. However, we found it nontrivial to implement `execute()` correctly with the non-reentrancy guarantee.
This reverts commit ef8a84421d.
Firebase is not yet ready to migrate to the new API. Will try again once we made the release and migrated them to CallCredentials2.
This will allow enabling Error Prone on JDK 10+ (after
updating the net.ltgt.errorprone plugin), and is also a
prerequisite to that plugin update.
Also remove net.ltgt.apt plugin, as Gradle has native
support for annotationProcessor.
This change is mainly to fix a test, but it also is an implementation of the proposal here: https://github.com/grpc/proposal/pull/79
In short:
* Do not do SRV or TXT lookups when the target name is `localhost`. This can be overriden by a system property
* Do not do SRV or TXT lookups when the target name is an IPv6 or IPv4 address. This _cannot_ be overriden. The constructed domains for these queries would themselves not be valid. (e.g. _grpclb._tcp.192.168.0.1)
* Speeds up initial connection when communicating over local host, since it is extremely uncommon that such a connection would need gRPCLB or SRV records
I expect to remove the system property after a release if no one asks about it.
This is a rename of the pre-existing Netty builder method, so aliases
were added to the Netty builders.
Fixes#4050. This API was a minor rename to the pre-existing Netty API,
so has already undergone API review and thus is not ExperimentalApi.
There is a known issue that causes DNS lookup issue when network
siwtchover on android. This issue is tracked separately in #4962.
This change simply disables DNS cache to avoid the issue on Android.
It appears everything was already working on Java 11, except
build-specific and testing issues. Updating to Netty 4.1.30 (#4940)
probably fixed the last true Java 11 incompatibility.
Fixes#4933
oracle10 is failing during setup with:
The command "bash install-jdk.sh -F 10 -L BCL --target $JAVA_HOME --workspace ${TRAVIS_HOME}/.cache/install-jdk" failed and exited with 8 during .
We should be adding support for Java 11 and dropping Java 9-10 anyway,
since Java 9-10 are unsupported.
Those overrides are kept for backward compatibility and convenience
for callers. Documentation already says implementations should not
override them. Making them final reduces confusion around which
override should be verified in tests and be overridden in forwarding
classes, thus prevents bugs caused by such confusion.
Returns a Channel that allows a LoadBalancer to make auxiliary RPCs on already-established application connections. We need this to implement client-side health-checking (#4932)
See comments on the API for its semantics.
Notable changes:
- Transports are modified to use InUseStateAggregator so that they can exclude RPCs made on Subchannel.asChannel() when reporting in-use state for idle mode.
- OobChannel shares the same Executor as Subchannel.asChannel(). Because the latter is not a ManagedChannel and doesn't have life-cycle, thus can't determine when to return the Executor to a pool, the Executor is now returned only when ManagedChannelImpl is terminated.
This change does 3 main things (in 3 commits):
1. Refactor the resolution runnable to be testable
2. Add Finer level logging to aid in debugging
3. Check that there are addresses before passing them to ManagedChannelImpl.
The transport test flakes at the timeout(100) about .05% of the time.
There's really no reason it should have a smaller timeout compared to
the other timeouts.
The timeout(250) wasn't flaking at all, but it should follow the
convention.
Kun Zhang
Elliotte Rusty Harold
Eric Anderson
Carl Mastrangelo
zpencer
Elliotte Harold
Eric Gribkoff
ZHANG Dapeng
Jiangtao Li
Thomas Broyer
Jihun Cho