eclipse - 使用 Eclipse Milo 连接到 OPC-UA 服务器在 BadHostUnknown 上失败
问题描述
我是 OPC-UA 和 Eclipse Milo 的新手，我正在尝试构建一个可以连接到我们刚刚购买的机器的 OPC-UA 服务器的客户端。
通过使用以下 Python 教程系列，我已经能够在我的笔记本电脑上设置一个简单的 OPC-UA 服务器： https: //www.youtube.com/watch?v=NbKeBfK3pfk。此外，我已经能够使用 Eclipse Milo 示例成功运行订阅示例以从该服务器读取一些值。
但是，我在连接到我们刚刚收到的机器的 OPC-UA 服务器时遇到了困难。我已经使用 UaExpert 客户端成功连接到该服务器，但我们想使用 Eclipse Milo 构建自己的客户端。我可以看到在使用 UaExpert 连接到服务器时出现了一些警告，这些警告似乎提供了有关该问题的线索，但我在服务器-客户端通信/OPC-UA 方面的经验太少，希望能得到一些帮助。我将解释当我使用 UaExpert 客户端时会发生什么，因为我一直在使用它来尝试诊断正在发生的事情。
我注意到，当我第一次启动 UaExpert 时，我收到以下可能相关的错误：
Discovery FindServersOnNetwork on opc.tcp://localhost:4840 failed (BadTimeout), falling back to FindServers
Discovery FindServers on opc.tpc://localhost:4840 failed (BadTimeout)
Discovery GetEndpoints on opc.tcp://localhost:4840 failed
我对网络真的很陌生，所以不确定这到底意味着什么。
我将概述我在尝试使 Eclipse Milo 的 SubscriptionExample 与这台机器的服务器一起工作时所遵循的过程。首先，我将 getEndpointUrl() 方法更改为我们正在使用的设备的 IP 地址：return "opc.tcp://11.23.1.1:4840"。我可以使用笔记本电脑上的 ping 11.23.1.1 成功 ping 设备。当我尝试使用此地址运行 SubscriptionExample 时，出现以下错误：
[NonceUtilSecureRandom] INFO o.e.m.o.stack.core.util.NonceUtil - SecureRandom seeded in 0ms.
18:36:23.879 [main] ERROR o.e.m.e.client.ClientExampleRunner - Error running client example: java.net.UnknownHostException: br-automation
java.util.concurrent.ExecutionException: java.net.UnknownHostException: br-automation
at java.util.concurrent.CompletableFuture.reportGet(Unknown Source)
at java.util.concurrent.CompletableFuture.get(Unknown Source)
at org.eclipse.milo.examples.client.SubscriptionExample.run(SubscriptionExample.java:50)
at org.eclipse.milo.examples.client.ClientExampleRunner.run(ClientExampleRunner.java:120)
at org.eclipse.milo.examples.client.SubscriptionExample.main(SubscriptionExample.java:42)
Caused by: java.net.UnknownHostException: br-automation
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(Unknown Source)
at java.net.InetAddress.getAddressesFromNameService(Unknown Source)
at java.net.InetAddress.getAllByName0(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getByName(Unknown Source)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:148)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at io.netty.util.internal.SocketUtils.addressByName(SocketUtils.java:145)
at io.netty.resolver.DefaultNameResolver.doResolve(DefaultNameResolver.java:43)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:63)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:55)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:57)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:32)
at io.netty.resolver.AbstractAddressResolver.resolve(AbstractAddressResolver.java:108)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect0(Bootstrap.java:200)
at io.netty.bootstrap.Bootstrap.access$000(Bootstrap.java:46)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:166)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:577)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:551)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:490)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:615)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:604)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84)
at io.netty.channel.AbstractChannel$AbstractUnsafe.safeSetSuccess(AbstractChannel.java:984)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:504)
at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417)
at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.lang.Thread.run(Unknown Source)
18:36:23.881 [ForkJoinPool.commonPool-worker-1] ERROR o.e.m.e.client.ClientExampleRunner - Error running example: java.net.UnknownHostException: br-automation
java.util.concurrent.ExecutionException: java.net.UnknownHostException: br-automation
at java.util.concurrent.CompletableFuture.reportGet(Unknown Source)
at java.util.concurrent.CompletableFuture.get(Unknown Source)
at org.eclipse.milo.examples.client.SubscriptionExample.run(SubscriptionExample.java:50)
at org.eclipse.milo.examples.client.ClientExampleRunner.run(ClientExampleRunner.java:120)
at org.eclipse.milo.examples.client.SubscriptionExample.main(SubscriptionExample.java:42)
Caused by: java.net.UnknownHostException: br-automation
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$2.lookupAllHostAddr(Unknown Source)
at java.net.InetAddress.getAddressesFromNameService(Unknown Source)
at java.net.InetAddress.getAllByName0(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getByName(Unknown Source)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:148)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at io.netty.util.internal.SocketUtils.addressByName(SocketUtils.java:145)
at io.netty.resolver.DefaultNameResolver.doResolve(DefaultNameResolver.java:43)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:63)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:55)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:57)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:32)
at io.netty.resolver.AbstractAddressResolver.resolve(AbstractAddressResolver.java:108)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect0(Bootstrap.java:200)
at io.netty.bootstrap.Bootstrap.access$000(Bootstrap.java:46)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:166)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:577)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:551)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:490)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:615)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:604)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84)
at io.netty.channel.AbstractChannel$AbstractUnsafe.safeSetSuccess(AbstractChannel.java:984)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:504)
at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417)
at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.lang.Thread.run(Unknown Source)
使用 UaExpert 时，“opc.tcp://11.23.1.1:4840”是我在使用自定义发现时添加新服务器时输入的服务器地址。当我输入此内容时，一个设备显示为该服务器的下拉列表，称为 B&R Embedded OPC-UA Server，因为 OPC-UA 服务器托管在机器中的 B&R 设备上。当我选择此设备进行连接时，我收到以下消息：
用于调用 GetEndpoints (br-automation) 的发现 URL 的主机名已替换为用于调用 FindServers (11.23.1.1) 的主机名。您还想用此主机名替换 EndpointURL 的主机名吗？
我必须接受此消息才能找到服务器，但我对到底发生了什么感到困惑。我假设用于查找服务器的端点和用于其他用途的端点存在差异？我发现网上的资源很难理解。在 UaExpert 日志中，连续三行日志报告“正在添加 URL：ocp.tcp://br-automation:4840”。然后它还会报告端点：“ocp.tcp://br-automation:4840”、应用程序 Uri 和安全策略（无）。如果我尝试将客户端的 getEndpointUrl 方法中的地址更改为 ocp.tcp://br-automation:4840 ，则会收到以下错误：
[main] INFO o.e.m.opcua.sdk.client.OpcUaClient - Eclipse Milo OPC UA Client SDK version: 0.4.3-SNAPSHOT
18:37:46.035 [main] ERROR o.e.m.e.client.ClientExampleRunner - Error getting client: java.util.concurrent.ExecutionException: java.net.UnknownHostException: br-automation
org.eclipse.milo.opcua.stack.core.UaException: java.util.concurrent.ExecutionException: java.net.UnknownHostException: br-automation
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.lambda$create$1(OpcUaClient.java:204)
at java.util.Optional.orElseGet(Unknown Source)
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.create(OpcUaClient.java:204)
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.create(OpcUaClient.java:201)
at org.eclipse.milo.examples.client.ClientExampleRunner.createClient(ClientExampleRunner.java:73)
at org.eclipse.milo.examples.client.ClientExampleRunner.run(ClientExampleRunner.java:94)
at org.eclipse.milo.examples.client.SubscriptionExample.main(SubscriptionExample.java:42)
Caused by: java.util.concurrent.ExecutionException: java.net.UnknownHostException: br-automation
at java.util.concurrent.CompletableFuture.reportGet(Unknown Source)
at java.util.concurrent.CompletableFuture.get(Unknown Source)
at org.eclipse.milo.opcua.sdk.client.OpcUaClient.create(OpcUaClient.java:180)
... 4 common frames omitted
Caused by: java.net.UnknownHostException: br-automation
at java.net.InetAddress.getAllByName0(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getByName(Unknown Source)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:148)
at io.netty.util.internal.SocketUtils$8.run(SocketUtils.java:145)
at java.security.AccessController.doPrivileged(Native Method)
at io.netty.util.internal.SocketUtils.addressByName(SocketUtils.java:145)
at io.netty.resolver.DefaultNameResolver.doResolve(DefaultNameResolver.java:43)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:63)
at io.netty.resolver.SimpleNameResolver.resolve(SimpleNameResolver.java:55)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:57)
at io.netty.resolver.InetSocketAddressResolver.doResolve(InetSocketAddressResolver.java:32)
at io.netty.resolver.AbstractAddressResolver.resolve(AbstractAddressResolver.java:108)
at io.netty.bootstrap.Bootstrap.doResolveAndConnect0(Bootstrap.java:200)
at io.netty.bootstrap.Bootstrap.access$000(Bootstrap.java:46)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:180)
at io.netty.bootstrap.Bootstrap$1.operationComplete(Bootstrap.java:166)
at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:577)
at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:551)
at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:490)
at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:615)
at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:604)
at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104)
at io.netty.channel.DefaultChannelPromise.trySuccess(DefaultChannelPromise.java:84)
at io.netty.channel.AbstractChannel$AbstractUnsafe.safeSetSuccess(AbstractChannel.java:984)
at io.netty.channel.AbstractChannel$AbstractUnsafe.register0(AbstractChannel.java:504)
at io.netty.channel.AbstractChannel$AbstractUnsafe.access$200(AbstractChannel.java:417)
at io.netty.channel.AbstractChannel$AbstractUnsafe$1.run(AbstractChannel.java:474)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.lang.Thread.run(Unknown Source)
我不知道这是否足以诊断问题的信息，但如果我能帮助我让 Eclipse Milo 服务器执行相同的过程并连接到机器的服务器，我将不胜感激。
解决方案
问题是您运行客户端的计算机无法将主机名“br-automation”解析为 IP 地址。
如果您无法将服务器配置为返回 IP 地址，则解决方案是手动重建EndpointDescription从 GetEndpoints 服务调用获得的 s，以便它们具有包含 IP 地址而不是主机名的端点 URL。这就是 UaExpert 在警告您更换主机名时在幕后所做的事情。
您可以在它被传递给 OpcUaClientConfig 之前使用它EndpointUtil#updateUrl来构建一个新的。EndpointDescription
推荐阅读
- swift - 从 ENUM 函数中调用外部类函数
- pagespeed - 这个页面速度结果是什么意思？
- typescript - 从有效属性名称列表中键入具有一个且只有一个属性的对象
- c# - Ajax 调用发布 0 或 null
- android - Android - javax.crypto.AEADBadTagException
- c# - 我可以在不创建新实例的情况下访问另一个用户控件中的表单控件吗？
- sonos - Sonos 云 API 队列
- javascript - jQuery Draggable 不会移动文本中的插入符号位置
- maven-2 - 如何从存储库中删除 Sonatype Nexus OSS(3) 组件？
- julia - Julia RemoteChanel 示例给出 UndefVarError