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Hedera™ Hashgraph SDK for Java
/*-
*
* Hedera Java SDK
*
* Copyright (C) 2020 - 2024 Hedera Hashgraph, LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.hedera.hashgraph.sdk;
import com.google.errorprone.annotations.Var;
import io.grpc.ChannelCredentials;
import io.grpc.ConnectivityState;
import io.grpc.Grpc;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.TlsChannelCredentials;
import io.grpc.inprocess.InProcessChannelBuilder;
import java.lang.module.ModuleDescriptor;
import java.time.Duration;
import java.time.Instant;
import java.util.Objects;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
import javax.annotation.Nullable;
/**
* Internal utility class.
*
* @param the n type
* @param the key t type
*/
abstract class BaseNode, KeyT> {
private static final int GET_STATE_INTERVAL_MILLIS = 50;
private static final int GET_STATE_TIMEOUT_MILLIS = 10000;
private static final int GET_STATE_MAX_ATTEMPTS = GET_STATE_TIMEOUT_MILLIS / GET_STATE_INTERVAL_MILLIS;
private boolean hasConnected = false;
protected final ExecutorService executor;
/**
* Address of this node
*/
protected final BaseNodeAddress address;
/**
* Timestamp of when this node will be considered healthy again
*/
protected Instant readmitTime;
/**
* The current backoff duration. Uses exponential backoff so think 1s, 2s, 4s, 8s, etc until maxBackoff is hit
*/
protected Duration currentBackoff;
/**
* Minimum backoff used by node when receiving a bad gRPC status
*/
protected Duration minBackoff;
/**
* Maximum backoff used by node when receiving a bad gRPC status
*/
protected Duration maxBackoff;
/**
* Number of times this node has received a bad gRPC status
*/
protected long badGrpcStatusCount;
@Nullable
protected ManagedChannel channel = null;
/**
* Constructor.
*
* @param address the node address
* @param executor the client
*/
protected BaseNode(BaseNodeAddress address, ExecutorService executor) {
this.executor = executor;
this.address = address;
this.currentBackoff = Client.DEFAULT_MIN_NODE_BACKOFF;
this.minBackoff = Client.DEFAULT_MIN_NODE_BACKOFF;
this.maxBackoff = Client.DEFAULT_MAX_NODE_BACKOFF;
this.readmitTime = Instant.EPOCH;
}
/**
* Constructor.
*
* @param node the node object
* @param address the address to assign
*/
protected BaseNode(N node, BaseNodeAddress address) {
this.address = address;
this.executor = node.executor;
this.minBackoff = node.minBackoff;
this.maxBackoff = node.maxBackoff;
this.readmitTime = node.readmitTime;
this.currentBackoff = node.currentBackoff;
this.badGrpcStatusCount = node.badGrpcStatusCount;
}
/**
* Return the local host ip address
*
* @return the authority address
*/
protected String getAuthority() {
return "127.0.0.1";
}
/**
* Extract the key list
*
* @return the key list
*/
abstract KeyT getKey();
/**
* Get the address of this node
*
* @return the address for the node
*/
BaseNodeAddress getAddress() {
return address;
}
/**
* Get the minimum backoff time
*
* @return the minimum backoff time
*/
synchronized Duration getMinBackoff() {
return minBackoff;
}
/**
* Set the minimum backoff tim
*
* @param minBackoff the minimum backoff time
* @return {@code this}
*/
synchronized N setMinBackoff(Duration minBackoff) {
if (currentBackoff == this.minBackoff) {
currentBackoff = minBackoff;
}
this.minBackoff = minBackoff;
// noinspection unchecked
return (N) this;
}
/**
* Get the maximum backoff time
*
* @return the maximum backoff time
*/
Duration getMaxBackoff() {
return maxBackoff;
}
/**
* Set the maximum backoff time
*
* @param maxBackoff the max backoff time
* @return {@code this}
*/
N setMaxBackoff(Duration maxBackoff) {
this.maxBackoff = maxBackoff;
// noinspection unchecked
return (N) this;
}
/**
* Get the number of times this node has received a bad gRPC status
*
* @return the count of bad grpc status
*/
long getBadGrpcStatusCount() {
return badGrpcStatusCount;
}
/**
* Extract the unhealthy backoff time remaining.
*
* @return the unhealthy backoff time remaining
*/
long unhealthyBackoffRemaining() {
return Math.max(0, readmitTime.toEpochMilli() - System.currentTimeMillis());
}
/**
* Determines if this is node is healthy.
* Healthy means the node has either not received any bad gRPC statuses, or if it has received bad gRPC status then
* the node backed off for a period of time.
*
* @return is the node healthy
*/
boolean isHealthy() {
return readmitTime.toEpochMilli() < Instant.now().toEpochMilli();
}
/**
* Used when a node has received a bad gRPC status
*/
synchronized void increaseBackoff() {
this.badGrpcStatusCount++;
this.readmitTime = Instant.now().plus(this.currentBackoff);
this.currentBackoff = currentBackoff.multipliedBy(2);
this.currentBackoff = currentBackoff.compareTo(maxBackoff) < 0 ? currentBackoff : maxBackoff;
}
/**
* Used when a node has not received a bad gRPC status.
* This means on each request that doesn't get a bad gRPC status the current backoff will be lowered. The point of
* this is to allow a node which has been performing poorly (receiving several bad gRPC status) to become used again
* once it stops receiving bad gRPC statuses.
*/
synchronized void decreaseBackoff() {
this.currentBackoff = currentBackoff.dividedBy(2);
this.currentBackoff = currentBackoff.compareTo(minBackoff) > 0 ? currentBackoff : minBackoff;
}
/**
* Get the amount of time the node has to wait until it's healthy again
*
* @return remaining back off time
*/
long getRemainingTimeForBackoff() {
return readmitTime.toEpochMilli() - System.currentTimeMillis();
}
/**
* Create TLS credentials when transport security is enabled
*
* @return the channel credentials
*/
ChannelCredentials getChannelCredentials() {
return TlsChannelCredentials.create();
}
/**
* Get the gRPC channel for this node
*
* @return the channel
*/
synchronized ManagedChannel getChannel() {
if (channel != null) {
return channel;
}
ManagedChannelBuilder channelBuilder;
if (address.isInProcess()) {
channelBuilder = InProcessChannelBuilder.forName(Objects.requireNonNull(address.getName()));
} else if (address.isTransportSecurity()) {
channelBuilder = Grpc.newChannelBuilder(address.toString(), getChannelCredentials());
String authority = getAuthority();
if (authority != null) {
channelBuilder = channelBuilder.overrideAuthority(authority);
}
} else {
channelBuilder = ManagedChannelBuilder.forTarget(address.toString()).usePlaintext();
}
channel = channelBuilder
.keepAliveTimeout(10, TimeUnit.SECONDS)
.keepAliveWithoutCalls(true)
.disableRetry()
.userAgent(getUserAgent())
.executor(executor)
.build();
return channel;
}
/**
* Did we fail to connect?
*
* @return did we fail to connect
*/
boolean channelFailedToConnect() {
return channelFailedToConnect(Instant.MAX);
}
boolean channelFailedToConnect(Instant timeoutTime) {
if (hasConnected) {
return false;
}
hasConnected = (getChannel().getState(true) == ConnectivityState.READY);
try {
for (@Var int i = 0; i < GET_STATE_MAX_ATTEMPTS && !hasConnected; i++) {
Duration currentTimeout = Duration.between(Instant.now(), timeoutTime);
if (currentTimeout.isNegative() || currentTimeout.isZero()) {
return false;
}
TimeUnit.MILLISECONDS.sleep(GET_STATE_INTERVAL_MILLIS);
hasConnected = (getChannel().getState(true) == ConnectivityState.READY);
}
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
return !hasConnected;
}
private CompletableFuture channelFailedToConnectAsync(int i, ConnectivityState state) {
hasConnected = (state == ConnectivityState.READY);
if (i >= GET_STATE_MAX_ATTEMPTS || hasConnected) {
return CompletableFuture.completedFuture(!hasConnected);
}
return Delayer.delayFor(GET_STATE_INTERVAL_MILLIS, executor).thenCompose(ignored -> {
return channelFailedToConnectAsync(i + 1, getChannel().getState(true));
});
}
/**
* Asynchronously determine if the channel failed to connect.
*
* @return did we fail to connect
*/
CompletableFuture channelFailedToConnectAsync() {
if (hasConnected) {
return CompletableFuture.completedFuture(false);
}
return channelFailedToConnectAsync(0, getChannel().getState(true));
}
/**
* Close the current nodes channel
*
* @param timeout the timeout value
* @throws InterruptedException thrown when a thread is interrupted while it's waiting, sleeping, or otherwise occupied
*/
synchronized void close(Duration timeout) throws InterruptedException {
if (channel != null) {
channel.shutdown();
channel.awaitTermination(timeout.getSeconds(), TimeUnit.SECONDS);
channel = null;
}
}
/**
* Extract the user agent string.
*
* @return the user agent string
*/
private String getUserAgent() {
var theModule = getClass().getModule();
var thePackage = getClass().getPackage();
String implementationVersion;
if (theModule.getName() == null) {
// running on classpath
implementationVersion =
thePackage != null ? thePackage.getImplementationVersion() : null;
} else {
// running on module path
implementationVersion =
theModule.getDescriptor().version().map(ModuleDescriptor.Version::toString).orElse(null);
}
return "hedera-sdk-java/" + ((implementationVersion != null) ? ("v" + implementationVersion) : "DEV");
}
}