Resolves#2716
- Add attributes to EquivalentAddressGroup
- Deprecate ResolvedServerInfoGroup by EquivalentAddressGroup
- Deprecate ResolvedServerInfo, because attributes for a single address
with an address group is not found to be useful.
- The changes on the NameResolver and LoadBalancer interfaces are backward-compatible
in the next release, with which implementors can switch to the new API smoothly.
As a related change, redefine the semantics of DnsNameResolver and
RoundRobinLoadBalancer:
- Before: DnsNameResolver returns all addresses in one address group.
RoundRobinLoadBalancer ignores the grouping of addresses and
round-robin on every single addresses. It doesn't work well with the
one-server-multiple-address setup, e.g., both IPv4 and IPv6 addresses
are returned for a single serve, even if they are put in the same
address group by the NameResolver.
- After: DnsNameResolver returns every address in its own
EAG. RoundRobinLoadBalancer takes an EAG as a whole, and only
round-robin on the list of EAGs. The new behavior is a better
interpretation of the EAGs, and really allows the case where one
server has more than one addresses (e.g., IPv4 and IPv6).
This change will affect users that use custom LoadBalancer with the
stock DnsNameResolver, and those who use custom NameResolver with the
stock RoundRobinLoadBalancer.
Users who use both the stock DnsNameResolver and RoundRobinLoadBalancer
or PickFirstBalancer will see no behavioral change. Because they will
still round-robin on individual addresses from DNS, or do pick-first on
all addresses from DNS (PickFirstBalancer flattens all addresses).
The result is a simpler API and reduction of boilderplates.
`keepAlivedManager#onTransportshutdown` should not be called in `transport.shutdown()` because it is possible that there are still open RPC streams, and maybe inactive, so keepalive is still needed.
Preparing to support server side keepalive.
For the convience on server side, not to use Ping `onSuccess()` callback to cancle shutdownFuture any more, instead, regard `onDataReceived()` as ping Ack and cancel shutdownFuture in it.
The balancer service attaches a token string for each Server entry it
sends to the client. The client has to set the token to the "lb-token"
header when assigning that Server entry to an RPC.
For convenience of testing, also implemented hashCode() and equals() for
PickResult.
The build (jdk version jdk1.8.0_91) produces some noise
```
/usr/local/google/home/zdapeng/git/grpc-java/core/src/main/java/io/grpc/LoadBalancer.java:196: warning - Tag @link: can't find pickSubchannel(PickSubchannelArgs) in io.grpc.LoadBalancer.SubchannelPicker
/usr/local/google/home/zdapeng/git/grpc-java/core/src/main/java/io/grpc/LoadBalancer.java:388: warning - Tag @link: can't find pickSubchannel(
PickSubchannelArgs) in io.grpc.LoadBalancer.SubchannelPicker
/usr/local/google/home/zdapeng/git/grpc-java/core/src/main/java/io/grpc/LoadBalancer.java:178: warning - Tag @link: can't find pickSubchannel(PickSubchannelArgs) in io.grpc.LoadBalancer.SubchannelPicker
3 warnings
:grpc-core:javadocJar
```
It seems nothing wrong with the javadoc and it could be a javac's bug, but here's a workaround.
fix JavaStyle and ErrorProne warnings found in internal weekly import:
- Calls to ExpectedException#expect should always be followed by exactly one statement.
- Do not mock 'java.util.concurrent.Future'
handleResolvedAddresses constructs subchannels for each address in
an EquivalentAddressGroup, sharing a reference to an immutable
Atrributes. However, as noted, this Attributes instance contains
a mutable AtomicReference, eventually causing subchannel state
changes to be improperly reflected in *all* subchannels of an
EquivalentAddressGroup.
Guava 20 introduced some overloading optimizations for Preconditions
that require using Guava 20+ at runtime. Unfortunately, Guava 20 removes
some things that is causing incompatibilities with other libraries, like
Cassandra. While the incompatibility did trigger some of those libraries
to improve compatibility for newer Guavas, we'd like to give the
community more time to work through it. See #2688
At this commit, we appear to be compatible with Guava 18+. It's not
clear if we want to actually "support" 18, but it did compile. Guava 17
doesn't have at least MoreObjects, directExecutor, and firstNotNull.
Guava 21 compiles without warnings, so it should be compatible with
Guava 22 when it is released.
One test method will fail with the upcoming Guava 22, but this won't
impact applications. I made MoreThrowables to avoid using any
known-deprecated Guava methods in our JARs, to reduce pain for those
stuck with old versions of gRPC in the future (July 2018).
In the stand-alone Android apps I removed unnecessary explicit deps
instead of syncing the version used.
Kun Zhang
Carl Mastrangelo
ZHANG Dapeng
kpayson64
Eric Gribkoff
Eric Anderson
Łukasz Strzałkowski
Jack Amadeo
Kun Zhang