ai.eloquent.raft

Interface RaftTransport

All Known Implementing Classes:

InstantTransport, LocalTransport, NetRaftTransport

public interface RaftTransport

This encapsulates all the non-functional components in EloquentRaftMember so that the remaining code can be easily unit-tested. That means this handles interfacing with EloquentChannel, as well as handling the timers.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	RaftTransport.Type The enumeration of different transport types.

Method Summary

Modifier and Type	Method and Description
void	bind(RaftAlgorithm listener) Register a listener for RPCs.
java.util.Collection<RaftAlgorithm>	boundAlgorithms() Get the collection of algorithms that have been bound to this transport.
void	broadcastTransport(java.lang.String sender, EloquentRaftProto.RaftMessage message) Broadcast an RPC request over the transport to all members of the cluster.
default void	broadcastTransport(java.lang.String sender, java.lang.Object messageProto)
static RaftTransport	create(java.lang.String serverName, RaftTransport.Type type) Create a new transport of the given type.
Span	expectedNetworkDelay() The expected delay, in milliseconds, for a round-trip on this transport.
default <E> E	getFuture(java.util.concurrent.CompletableFuture<E> future, java.time.Duration timeout) Get a future.
default java.lang.String	messageType(EloquentRaftProto.RaftMessage messageProto) For debugging, get the message type of a given message proto object.
static EloquentRaftProto.RaftMessage	mkRaftMessage(java.lang.String sender, java.lang.Object requestProto) Create a non-blocking RPC.
static EloquentRaftProto.RaftMessage	mkRaftMessage(java.lang.String sender, java.lang.Object requestProto, boolean isRPC) Create an RPC request to send over the transport.
static EloquentRaftProto.RaftMessage	mkRaftRPC(java.lang.String sender, java.lang.Object requestProto) Create a blocking RPC.
default long	now() The current (local) time on the transport.
void	rpcTransport(java.lang.String sender, java.lang.String destination, EloquentRaftProto.RaftMessage message, java.util.function.Consumer<EloquentRaftProto.RaftMessage> onResponseReceived, java.lang.Runnable onTimeout, long timeout) Send an RPC request over the transport, expecting a reply.
default void	rpcTransport(java.lang.String sender, java.lang.String destination, java.lang.Object message, java.util.function.Consumer<EloquentRaftProto.RaftMessage> onResponseReceived, java.lang.Runnable onTimeout, long timeout)
default <E> java.util.concurrent.CompletableFuture<E>	rpcTransportAsFuture(java.lang.String sender, java.lang.String destination, java.lang.Object message, java.util.function.BiFunction<EloquentRaftProto.RaftMessage,java.lang.Throwable,E> onResponseReceived, java.util.function.Consumer<java.lang.Runnable> runMethod)
default <E> java.util.concurrent.CompletableFuture<E>	rpcTransportAsFuture(java.lang.String sender, java.lang.String destination, java.lang.Object message, java.util.function.BiFunction<EloquentRaftProto.RaftMessage,java.lang.Throwable,E> onResponseReceived, java.util.function.Consumer<java.lang.Runnable> runMethod, long timeout)
default void	schedule(SafeTimerTask timerTask, long delay) Schedule an event every |period| seconds.
default void	scheduleAtFixedRate(SafeTimerTask timerTask, long period) Schedule an event every |period| seconds.
void	sendTransport(java.lang.String sender, java.lang.String destination, EloquentRaftProto.RaftMessage message) Send an RPC request over the transport, not necessarily expecting a reply.
default void	sendTransport(java.lang.String sender, java.lang.String destination, java.lang.Object messageProto)
default void	sleep(long millis) Sleep for the given number of milliseconds.
default void	start() For unit tests primarily -- most transports don't need to be started explicitly
default void	stop() For unit tests primarily -- stop this transport and clean up if necessary.
default boolean	threadsCanBlock() If true, we are allowed to block while running on this transport.

Method Detail

bind

void bind(RaftAlgorithm listener)
   throws java.io.IOException

Register a listener for RPCs. This must be idempotent!

Parameters:

listener - The listener that should be called on all received RPC requests.

Throws:

java.io.IOException

boundAlgorithms

java.util.Collection<RaftAlgorithm> boundAlgorithms()

Get the collection of algorithms that have been bound to this transport. This is primarily useful for unit testing.

rpcTransport

void rpcTransport(java.lang.String sender,
                  java.lang.String destination,
                  EloquentRaftProto.RaftMessage message,
                  java.util.function.Consumer<EloquentRaftProto.RaftMessage> onResponseReceived,
                  java.lang.Runnable onTimeout,
                  long timeout)

Send an RPC request over the transport, expecting a reply.

Parameters:

sender - The name of the node sending the message. In many implementations, this is redundant.

destination - The destination we are sending the message to. This is a server name on the same cluster as the node this transport is bound to.

message - The message to send, as a EloquentRaftProto.RaftMessage.

onResponseReceived - The callback to run when a response is received from the server for the RPC. Either this or onTimeout is always called.

onTimeout - Called when no response is received in the given timeout threshold.

timeout - The number of milliseconds to wait before considering an RPC timed out.

sendTransport

void sendTransport(java.lang.String sender,
                   java.lang.String destination,
                   EloquentRaftProto.RaftMessage message)

Send an RPC request over the transport, not necessarily expecting a reply.

Parameters:

sender - The name of the node sending the message. In many implementations, this is redundant.

destination - The destination we are sending the message to. This is a server name on the same cluster as the node this transport is bound to.

message - The message to send, as a EloquentRaftProto.RaftMessage.

broadcastTransport

void broadcastTransport(java.lang.String sender,
                        EloquentRaftProto.RaftMessage message)

Broadcast an RPC request over the transport to all members of the cluster.

Parameters:

sender - The name of the node sending the message. In many implementations, this is redundant.

message - The message to send, as a EloquentRaftProto.RaftMessage.

expectedNetworkDelay

Span expectedNetworkDelay()

The expected delay, in milliseconds, for a round-trip on this transport. This is used to calibrate the Raft algorithm, and to test the unit tests.

start

default void start()

For unit tests primarily -- most transports don't need to be started explicitly

stop

default void stop()

For unit tests primarily -- stop this transport and clean up if necessary.

threadsCanBlock

default boolean threadsCanBlock()

If true, we are allowed to block while running on this transport. This is useful for, e.g., unit tests. But, in general, we should try to not block as much as posisble. Defaults to false.

now

default long now()

The current (local) time on the transport. This is usually System.currentTimeMillis() if this isn't a mock.

sleep

default void sleep(long millis)

Sleep for the given number of milliseconds. This is purely for mocking for tests.

scheduleAtFixedRate

default void scheduleAtFixedRate(SafeTimerTask timerTask,
                                 long period)

Schedule an event every |period| seconds. This is an alias for SafeTimer.scheduleAtFixedRate(SafeTimerTask, long, long), but mockable

schedule

default void schedule(SafeTimerTask timerTask,
                      long delay)

Schedule an event every |period| seconds. This is an alias for SafeTimer.schedule(SafeTimerTask, long), but mockable

getFuture

default <E> E getFuture(java.util.concurrent.CompletableFuture<E> future,
                        java.time.Duration timeout)
                 throws java.lang.InterruptedException,
                        java.util.concurrent.ExecutionException,
                        java.util.concurrent.TimeoutException

Get a future. This is just a mockable alias for CompletableFuture.get(long, TimeUnit).

Throws:

java.lang.InterruptedException

java.util.concurrent.ExecutionException

java.util.concurrent.TimeoutException

sendTransport

default void sendTransport(java.lang.String sender,
                           java.lang.String destination,
                           java.lang.Object messageProto)

See Also:

sendTransport(String, String, EloquentRaftProto.RaftMessage)

broadcastTransport

default void broadcastTransport(java.lang.String sender,
                                java.lang.Object messageProto)

See Also:

broadcastTransport(String, EloquentRaftProto.RaftMessage)

rpcTransport

default void rpcTransport(java.lang.String sender,
                          java.lang.String destination,
                          java.lang.Object message,
                          java.util.function.Consumer<EloquentRaftProto.RaftMessage> onResponseReceived,
                          java.lang.Runnable onTimeout,
                          long timeout)

See Also:

rpcTransport(String, String, EloquentRaftProto.RaftMessage, Consumer, Runnable, long)

rpcTransportAsFuture

default <E> java.util.concurrent.CompletableFuture<E> rpcTransportAsFuture(java.lang.String sender,
                                                                           java.lang.String destination,
                                                                           java.lang.Object message,
                                                                           java.util.function.BiFunction<EloquentRaftProto.RaftMessage,java.lang.Throwable,E> onResponseReceived,
                                                                           java.util.function.Consumer<java.lang.Runnable> runMethod,
                                                                           long timeout)

See Also:

rpcTransport(String, String, EloquentRaftProto.RaftMessage, Consumer, Runnable, long)

rpcTransportAsFuture

default <E> java.util.concurrent.CompletableFuture<E> rpcTransportAsFuture(java.lang.String sender,
                                                                           java.lang.String destination,
                                                                           java.lang.Object message,
                                                                           java.util.function.BiFunction<EloquentRaftProto.RaftMessage,java.lang.Throwable,E> onResponseReceived,
                                                                           java.util.function.Consumer<java.lang.Runnable> runMethod)

See Also:

rpcTransport(String, String, EloquentRaftProto.RaftMessage, Consumer, Runnable, long)

mkRaftMessage

static EloquentRaftProto.RaftMessage mkRaftMessage(java.lang.String sender,
                                                   java.lang.Object requestProto,
                                                   boolean isRPC)

Create an RPC request to send over the transport. This is tagged as an RPC, and then the appropriate request is populated in the resulting object.

Parameters:

requestProto - The proto of the request, which we'll wrap in a raft request.

Returns:

A Raft RPC request proto we can send to the receiver.

mkRaftMessage

static EloquentRaftProto.RaftMessage mkRaftMessage(java.lang.String sender,
                                                   java.lang.Object requestProto)

Create a non-blocking RPC. @see #mkRaftMessage(String, Object, boolean)

mkRaftRPC

static EloquentRaftProto.RaftMessage mkRaftRPC(java.lang.String sender,
                                               java.lang.Object requestProto)

Create a blocking RPC. @see #mkRaftMessage(Object, boolean)

create

static RaftTransport create(java.lang.String serverName,
                            RaftTransport.Type type)
                     throws java.io.IOException

Create a new transport of the given type.

Parameters:

serverName - The name of us (our server)

type - The type of transport to create.

Returns:

A transport of the given type.

Throws:

java.io.IOException - Thrown if we could not create the given transport.

messageType

default java.lang.String messageType(EloquentRaftProto.RaftMessage messageProto)

For debugging, get the message type of a given message proto object.

Parameters:

messageProto - A raft message, of presumably unknown type.

Returns:

The type of the message