Always return a completed future from `TransportSet`. If a (real) transport has not been created (e.g., in reconnect back-off), a `DelayedClientTransport` will be returned.
Eventually we will get rid of the transport futures everywhere, and have streams always __owned__ by some transports.
DelayedClientTransport
----------------------
After we get rid of the transport future, this is what `ClientCallImpl` and `LoadBalancer` get when a real transport has not been created yet. It buffers new streams and pings until `setTransport()` is called, after which point all buffered and future streams/pings are transferred to the real transport.
If a buffered stream is cancelled, `DelayedClientTransport` will remove it from the buffer list, thus #1342 will be resolved after the larger refactoring is complete.
This PR only makes `TransportSet` use `DelayedClientTransport`. Follow-up changes will be made to allow `LoadBalancer.pickTransport()` to return null, in which case `ManagedChannelImpl` will give `ClientCallImpl` a `DelayedClientTransport`.
Changes to ClientTransport shutdown semantics
---------------------------------------------
Previously when shutdown() is called, `ClientTransport` should not accept newStream(), and when all existing streams have been closed, `ClientTransport` is terminated. Only when a transport is terminated would a transport owner (e.g., `TransportSet`) remove the reference to it.
`DelayedClientTransport` brings about a new case: when `setTransport()` is called, we switch to the real transport and no longer need the delayed transport. This is achieved by calling `shutdown()` on the delayed transport and letting it terminate. However, as the delayed transport has already been handed out to users, we would like `newStream()` to keep working for them, even though the delayed transport is already shut down and terminated.
In order to make it easy to manage the life-cycle of `DelayedClientTransport`, we redefine the shutdown semantics of transport:
- A transport can own a stream. Typically the transport owns the streams
it creates, but there may be exceptions. `DelayedClientTransport` DOES
NOT OWN the streams it returns from `newStream()` after `setTransport()`
has been called. Instead, the ownership would be transferred to the
real transport.
- After `shutdown()` has been called, the transport stops owning new
streams, and `newStream()` may still succeed. With this idea,
`DelayedClientTransport`, even when terminated, will continue
passing `newStream()` to the real transport.
- When a transport is in shutdown state, and it doesn't own any stream,
it then can enter terminated state.
ManagedClientTransport / ClientTransport
----------------------------------------
Remove life-cycle interfaces from `ClientTransport`, and put them in its subclass - `ManagedClientTransport`, with the same idea that we have `Channel` and `ManagedChannel`. Only the one who creates the transport will get `ManagedClientTransport` thus is able to start and shutdown the transport. The users of transport, e.g., `LoadBalancer`, can only get `ClientTransport` thus are not alter its state. This change clarifies the responsibility of transport life-cycle management.
Fix TransportSet shutdown semantics
-----------------------------------
Currently, if `TransportSet.shutdown()` has been called, it no longer create new transports, which is wrong.
The correct semantics of `TransportSet.shutdown()` should be:
- Shutdown all transports, thus stop new streams being created on them
- Stop `obtainActiveTransport()` from returning transports
- Streams that already created, including those buffered in delayed transport, should continue. That means if delayed transport has buffered streams, we should let the existing reconnect task continue.
This provides more structured data into the application for it to do
special handling.
In general, we would hope most people don't need this functionality, but
it is a good escape hatch to allow users to workaround infrastructure
problems.
This reverts commit eca1f7c1d6.
We want to preserve the status message identical to what the server
sent. We'll need a better way to communicate debugging details.
- Channel builders decide the default port based on whether TLS is used.
- Channel builders populate the default port via an Attributes object
passed to NameResolver.Factory#newNameResolver
- NameResolverRegistry contains all the official NameResolvers. Users
can also add custom NameResolvers to it. It looks up NameResolver by
try-and-fail. It is the default NameResolver.Factory for builders.
DnsNameResolver.
- Pass target as Strings instead of URIs from the channel builder to
ManagedChannelImpl. A target string is not necessarily a valid URI, in
which case ManagedChannelImpl will add "dns:///" to the beginning of
the target and use it as URI.
- DnsNameResolver will require scheme "dns" to be present. It no longer
allows scheme-absent URIs.
- Add NameResolver and LoadBalancer interfaces.
- ManagedChannelImpl now uses NameResolver and LoadBalancer for
transport selection, which may return transports to multiple
addresses.
- Transports are still owned by ManagedChannelImpl, which implements
TransportManager interface that is provided to LoadBalancer, so that
LoadBalancer doesn't worry about Transport lifecycles.
- Channel builders can be created by forTarget() that accepts the fully
qualified target name, which is an URI. (TODO) it's not tested.
- The old address-based construction pattern is supported by using
AbstractManagedChannelImplBuilder.DirectAddressNameResolver.
- (TODO) DnsNameResolver and SimpleLoadBalancer are currently
incomplete. They merely work for the single-address scenario.
We want to allow overriding authority in the ManagedChannelBuilder for
testing. In doing that, we basically require that all Channels support
authority. In reality, this simplifies things and is already being done
by the C implementation, as their unix domain socket support uses
"localhost" just like our in-process transport now does.
We can debate some whether "localhost" is really the most appropriate
authority for the in-process transport, but that should probably happen
later since "localhost" is "good enough" for now.
Negotiation failure results in a RuntimeException, which is not properly handled by the okhttp code, resulting in the client hanging.
Refactored the code to shutdown the transport when TLS negotiation fails.
This provides an API for applications to use gRPC without using
ExperimentalApis. It also allows swapping out a transport implementation
in the future.
Client:
* New ManagedChannel abstract class.
* Adding ping to Channel.
* Moving builders and implementations to internal.
Server:
* Added lifecycle management API to Server (mirroring ManagedChannel).
* Moved ServerImpl, AbstractServerBuilder and handler registries to internal.
* New ServerBuilder abstract class (mirroring ManagedChannelBuilder).
Fixes#545
The URI no longer needs to be provided to the Credential explicitly,
which prevents needing to know a magic string and allows using the same
Credential with multiple services.
The current process of building a channel is a bit complicated in that transports have to provide a own shutdown hook to the channel builder in order to close shared executors. This somewhat entagled creation pattern makes it difficult to separate the process of channel building from transport building. Better separating these two should make the code more readable and maintainable moving forward.
Reserve io.grpc for public API only, and all internal stuff in core to
io.grpc.internal, including the non-stable transport API.
Raise the netty/okhttp/inprocess subpackages one level up to io.grpc,
because they are public API and entry points for most users.
Details:
- Rename io.grpc.transport to io.grpc.internal;
- Move SharedResourceHolder and SerializingExecutor to io.grpc.internal
- Rename io.grpc.transport.{netty|okhttp|inprocess} to
io.grpc.{netty|okhttp|inprocess}
Forgot to add this last file
updated method name
Remove unused function
Remove helper function for threshold edge detection
Remove helper function for threshold edge detection
Re make listener abstract
Resolves#511.
- In generated code, make CONFIG private and METHOD_* fields public.
METHOD_* fields are MethodDescriptors now, users of the CONFIG field
should switch to using the METHOD_* fields.
- Move MethodType into MethodDescriptor (#529).
- Unify the fully qualified method name. It is fully qualified service
name + slash + short method name. It doesn't have the leading slash.
- HandlerRegistry switches the key from short method name to fully
qualified method name.
On Android platform, the constructor using hostname will iterate through all solved ip address for making connection.
Before we implement happy eyeballs, this could be a workaround for Android users.
1. Move DEFAULT_CONNECTION_SPEC to OkHttpChannelBuilder
2. make OkHttpClientTransport package-private
3. Rename OkHttpChannelBuilder.setConnectionSpec to connectionSpec
1. update connection window when receives DATA for existed streams.
2. kill the connection when receives unknown (not exist and never existed) stream id.
isReady() can provide pushback while the call is in progress, but it
can also provide the pushback necessary when the client creates more
streams than permitted by MAX_CONCURRENT_STREAMS.
As part of this commit, OkHttp is now calling onReady() after call
creation (it previously never called onReady()).
Kun Zhang