* Remove else, make it easier to read
* Ready subchanns list will be at max the same as the input list
* Make status private, add pkg-private getter for tests
* Remove empty field, cache size, simplify logic
Make list unmodifiable. Document index with GuardedBy (see #nextSubchannel())
add `getAttributes()` to `ClientStream` and `ClientCall` to be able to share clientTransport
information such as socket TOS with higher lever API's, once the RPC picks up an active transport that is ready to use.
Previously it does it at shutdown, which was wrong because executor may
still be used before the server is terminated.
Resolves#2034
Uses ObjectPool to make this change testable. Cleans up test and makes
it mostly single-threaded, except for two deadlock tests that have to be
multi-threaded.
If a LoadBalancer2 is passed in, the builder will create ManagedChannelImpl2 instead of ManagedChannelImpl. This allows us to test the LBv2 classes on a large scale.
1. Adapt to LoadBalancer2 interface. Channel holds on to a single
DelayedClientTransport2.
2. Lock-free: every channel state mutation, including Subchannel
mutations, calling into LoadBalancer, idleness and shutdown, is made
from channelExecutor.
3. Idleness grace period is no longer needed.
In upstream, Census is renamed to "Instrumentation". `com.google.census` is renamed to `com.google.instrumentation.stats`.
In gRPC, "census" in every name is replaced by "stats".
Besides API changes, this implementation is also up-to-date with the
latest design:
1. Delegate to round-robin and pick-first policies if requested by
the naming system.
2. OOB channels to LoadBalancer always use the LB authority provided by
the naming system.
3. Never send application RPCs to balancer addresses, even if the
address returns UNIMPLEMENTED error.
"Because of spurious wakeups, wait() must always be called in a loop".
Got rid of wait().
"If you return or throw from a finally, then values returned or thrown from the try-catch block will be ignored. Consider using try-with-resources instead."
Ignored the exception thrown from finally.
1. Use ChannelExecutor to run callbacks. Now callbacks are no longer
run under the delayed transport lock.
2. Use explicit picker version instead of relying on identity equality
to detect new pickers. Rationale: if reprocess() is called again with
the same picker, all pending streams will be reprocessed by this picker
again, thus there is no reason to leave out the racing new stream.
* Fork DelayedClientTransport into DelayedClientTransport2, and fix a race
on it. Consider the following sequence:
1. Channel is created. Picker is initially null
2. Channel has a new RPC. Because picker is null, the delayed transport
is picked, but newStream() is not called yet.
3. LoadBalancer updates a new picker to Channel. Channel runs
reprocess() but does nothing because no pending stream is there.
4. newStream() called on the delayed transport.
In previous implementation, newStream() on step 4 will not see the
picker. It will only use the next picker.
After this change, delayed transport would save the latest picker and
use it on newStream(), which is the desired behavior.
Also deleted all the code that will not be used after the LB refactor.
* Also fixed a bug: newStream() should always return a failing stream if it's shutdown. Previously it's not doing so if picker is not null.
OutputStreamAdapter is a private class, and is only ever called by two
places: ByteStreams.copy, which never calls the single byte method, and
DrainTo, which potentially can. There are two classes that implement
DrainTo, which is primarily ProtoInputStream. It calls
MessageLite.writeTo(OutputStream) or back again to ByteStreams.copy.
MessageLite.writeTo in turn wraps the OutputStream in a
CodedOutputStream.OutputStreamEncoder, which then never calls the single
byte version. Thus, all know implementations never call the single
byte override.
Additionally, it is well known that the single byte write is slow, and
is expected to be wrapped in a BufferedOutputStream if there are many
small writes.
- Remove unused variable terminated from TransportListener#transportTerminated
- Do not mention getLock in the javadoc of InUseStateAggregator2#handleNotInUse
FackeClock used PriorityQueue for storing tasks which is not
thread-safe, and caused flake
> io.grpc.internal.ClientCallImplTest > deadlineExceededBeforeCallStarted FAILED
> java.lang.ArrayIndexOutOfBoundsException: -1
> at java.util.PriorityQueue.removeAt(PriorityQueue.java:619)
> at java.util.PriorityQueue.remove(PriorityQueue.java:378)
> at io.grpc.internal.FakeClock$ScheduledTask.cancel(FakeClock.java:89)
> at io.grpc.internal.ClientCallImpl.removeContextListenerAndCancelDeadlineFuture(ClientCallImpl.java:296)
> at io.grpc.internal.ClientCallImpl.start(ClientCallImpl.java:250)
> at io.grpc.internal.ClientCallImplTest.deadlineExceededBeforeCallStarted(ClientCallImplTest.java:615)
Document the threading requirements.
Turn all metrics to volatile because callEnded() may not be synchronized
with other metric-updating methods in the case where the RPC is closed
because of transport error or cancellation from the other side.
Remove precondition checks thus allow metrics updating methods to be
called after callEnded() has been called, which may happen since the
application may not be aware when the RPC is closed by the transport.
This is the first step of a major refactor for the LoadBalancer-related part of Channel impl (#1600). It forks TransportSet into InternalSubchannel and makes changes on it.
What's changed:
- InternalSubchannel no longer has delayed transport, thus will not buffer
streams when a READY real transport is absent.
- When there isn't a READ real transport, obtainActiveTransport() will
return null.
- InternalSubchannel is no longer a ManagedChannel
- Overhauled Callback interface, with onStateChange() replacing the
adhoc transport event methods.
- Call out channelExecutor, which is a serializing executor that runs
the Callback.
The first commit is an unmodified copy of the files that are being forked. Please review the second commit which changes on the forked files.
Eric Anderson
Kun Zhang
Łukasz Strzałkowski
ZHANG Dapeng
Eric Gribkoff
Carl Mastrangelo
Anuraag Agrawal
Kenji Kaneda
Michael Avrukin
Kenji Kaneda