How to connect to Neptune using Version 4 Signing dependency - gremlin

Question

I have an EC2 instance that can connect to gremlin using the Gremlin Console, or by pulling in this repository and running the maven command.
However, when I use the recommended Version 4 signing dependency:
dependencies {
compile(
...
// neptune sigv4
[group: "com.amazonaws", name:"aws-java-sdk-core", version: "1.11.307"],
[group: "com.amazonaws", name:"amazon-neptune-sigv4-signer", version: "1.0"],
[group: "com.amazonaws", name:"amazon-neptune-gremlin-java-sigv4", version: "1.0"],
...
)
}
On a very similar hello world program:
package com.test.neptune;
import org.apache.tinkerpop.gremlin.driver.Client;
import org.apache.tinkerpop.gremlin.driver.Cluster;
import org.apache.tinkerpop.gremlin.driver.Result;
import org.apache.tinkerpop.gremlin.driver.ResultSet;
import org.apache.tinkerpop.gremlin.driver.SigV4WebSocketChannelizer;
import org.neo4j.cypher.internal.frontend.v2_3.repeat;
public class NeptuneExampleCopy {
private static final String NEPTUNE_ENDPOINT = "my.endpoint.url";
private static final int NEPTUNE_PORT = 0;
public static void main(String[] args) {
// connect to the neptune cluster
final Cluster cluster = Cluster.build()
.addContactPoint(NEPTUNE_ENDPOINT)
.port(NEPTUNE_PORT)
.channelizer(SigV4WebSocketChannelizer.class)
.create();
// run a traversal, print the results
final Client client = cluster.connect();
final ResultSet rs = client.submit("g.V().count()");
for (Result r : rs) {
System.out.println(r);
}
// close the cluster
cluster.close();
}
}
Gradle throws the following exception:
Apr 25, 2019 5:24:21 PM io.netty.channel.ChannelInitializer exceptionCaught
WARNING: Failed to initialize a channel. Closing: [id: 0xd894eb28]
com.amazon.neptune.gremlin.driver.exception.SigV4PropertiesNotFoundException: Unable to load SigV4 properties from any of the providers
at com.amazon.neptune.gremlin.driver.sigv4.ChainedSigV4PropertiesProvider.getSigV4Properties(ChainedSigV4PropertiesProvider.java:74)
at com.amazon.neptune.gremlin.driver.sigv4.AwsSigV4ClientHandshaker.loadProperties(AwsSigV4ClientHandshaker.java:102)
at com.amazon.neptune.gremlin.driver.sigv4.AwsSigV4ClientHandshaker.<init>(AwsSigV4ClientHandshaker.java:64)
at org.apache.tinkerpop.gremlin.driver.SigV4WebSocketChannelizer.createHandler(SigV4WebSocketChannelizer.java:210)
at org.apache.tinkerpop.gremlin.driver.SigV4WebSocketChannelizer.configure(SigV4WebSocketChannelizer.java:176)
at org.apache.tinkerpop.gremlin.driver.Channelizer$AbstractChannelizer.initChannel(Channelizer.java:140)
at org.apache.tinkerpop.gremlin.driver.Channelizer$AbstractChannelizer.initChannel(Channelizer.java:92)
at io.netty.channel.ChannelInitializer.initChannel(ChannelInitializer.java:113)
at io.netty.channel.ChannelInitializer.handlerAdded(ChannelInitializer.java:105)
at io.netty.channel.DefaultChannelPipeline.callHandlerAdded0(DefaultChannelPipeline.java:617)
at io.netty.channel.DefaultChannelPipeline.access$000(DefaultChannelPipeline.java:46)
at io.netty.channel.DefaultChannelPipeline$PendingHandlerAddedTask.execute(DefaultChannelPipeline.java:1467)
at io.netty.channel.DefaultChannelPipeline.callHandlerAddedForAllHandlers(DefaultChannelPipeline.java:1141)
at io.netty.channel.DefaultChannelPipeline.invokeHandlerAddedIfNeeded(DefaultChannelPipeline.java:666)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:510)
at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:423)
at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:482)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:463)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886)
at java.lang.Thread.run(Thread.java:748)
Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: java.util.concurrent.TimeoutException: Timed out while waiting for an available host - check the client configuration and connectivity to the server if this message persists
at org.apache.tinkerpop.gremlin.driver.Client.submit(Client.java:214)
at org.apache.tinkerpop.gremlin.driver.Client.submit(Client.java:198)
at com.test.neptune.NeptuneExampleCopy.main(NeptuneExampleCopy.java:25)
Caused by: java.lang.RuntimeException: java.util.concurrent.TimeoutException: Timed out while waiting for an available host - check the client configuration and connectivity to the server if this message persists
at org.apache.tinkerpop.gremlin.driver.Client.submitAsync(Client.java:310)
at org.apache.tinkerpop.gremlin.driver.Client.submitAsync(Client.java:242)
at org.apache.tinkerpop.gremlin.driver.Client.submit(Client.java:212)
... 2 more
Caused by: java.util.concurrent.TimeoutException: Timed out while waiting for an available host - check the client configuration and connectivity to the server if this message persists
at org.apache.tinkerpop.gremlin.driver.Client$ClusteredClient.chooseConnection(Client.java:499)
at org.apache.tinkerpop.gremlin.driver.Client.submitAsync(Client.java:305)
... 4 more
Apr 25, 2019 5:24:22 PM io.netty.channel.ChannelInitializer exceptionCaught
WARNING: Failed to initialize a channel. Closing: [id: 0xc3ff34e0]
com.amazon.neptune.gremlin.driver.exception.SigV4PropertiesNotFoundException: Unable to load SigV4 properties from any of the providers
at com.amazon.neptune.gremlin.driver.sigv4.ChainedSigV4PropertiesProvider.getSigV4Properties(ChainedSigV4PropertiesProvider.java:74)
at com.amazon.neptune.gremlin.driver.sigv4.AwsSigV4ClientHandshaker.loadProperties(AwsSigV4ClientHandshaker.java:102)
at com.amazon.neptune.gremlin.driver.sigv4.AwsSigV4ClientHandshaker.<init>(AwsSigV4ClientHandshaker.java:64)
at org.apache.tinkerpop.gremlin.driver.SigV4WebSocketChannelizer.createHandler(SigV4WebSocketChannelizer.java:210)
at org.apache.tinkerpop.gremlin.driver.SigV4WebSocketChannelizer.configure(SigV4WebSocketChannelizer.java:176)
at org.apache.tinkerpop.gremlin.driver.Channelizer$AbstractChannelizer.initChannel(Channelizer.java:140)
at org.apache.tinkerpop.gremlin.driver.Channelizer$AbstractChannelizer.initChannel(Channelizer.java:92)
at io.netty.channel.ChannelInitializer.initChannel(ChannelInitializer.java:113)
How could this code be fixed? Is there a better Version 4 signing dependency?

Answer 1

SigV4 handler tries to fetch your AWS Credentials through multiple credential providers. If no credential provider was initialized, then you are bound to see this exception. How have you initialized your AWS Credentials? You could use any of the standard sources, like environment variables, or JVM system properties or the like. See the documentation below for more details:
https://docs.aws.amazon.com/neptune/latest/userguide/iam-auth-connecting-gremlin-java.html
Update: Do make sure you are using the latest versions of all the packages and dependencies.
For example:
// neptune sigv4 [group: "com.amazonaws",
name:"aws-java-sdk-core", version: "1.11.542"],
[group: "com.amazonaws",
name:"amazon-neptune-sigv4-signer", version: "1.0.4"],
[group: "com.amazonaws",
name:"amazon-neptune-gremlin-java-sigv4", version: "1.0.5"],
// for neptune [group: "org.apache.tinkerpop",
name: "gremlin-driver", version: "3.4.1"]