etcd - 尝试按前缀删除所有键并重新放置时，txn 请求中给出的重复键

Question

正在尝试使用 coreos/jetcd 用于更新 etcd 中的 haproxy 设置来自Java代码。

我想要实现的是:

删除单个主机的所有端点

添加给定主机的更新数据

我想通过前缀删除所有键，并将实际数据作为原子操作放入 etcd。

这就是我尝试使用 etcd 事务的原因。我的代码是:

Op.DeleteOp deleteOp = Op.delete(
        fromString(prefix),
        DeleteOption.newBuilder().withPrefix(fromString(prefix)).build()
);
Txn tx = kvClient.txn().Else(deleteOp);
newKvs.forEach((k,v) -> {
    tx.Else(Op.put(fromString(k), fromString(v), DEFAULT));
});
try {
    tx.commit().get();
} catch (InterruptedException | ExecutionException e) {
    log.error("ETCD transaction failed", e);
    throw new RuntimeException(e);
}

使用 ETCD v3 API (etcd v3.2.9)。 KVstore 最初是空的，我想添加 3 条记录。 prefix值(value)是:

/proxy-service/hosts/example.com

和 kvs是一张 map :

"/proxy-service/hosts/example.com/FTP/0" -> "localhost:10021"
"/proxy-service/hosts/example.com/HTTPS/0" -> "localhost:10443"
"/proxy-service/hosts/example.com/HTTP/0" -> "localhost:10080"

commit().get() 上发生异常符合以下根本原因:

Caused by: io.grpc.StatusRuntimeException: INVALID_ARGUMENT: etcdserver: duplicate key given in txn request
    at io.grpc.Status.asRuntimeException(Status.java:526)
    at io.grpc.stub.ClientCalls$UnaryStreamToFuture.onClose(ClientCalls.java:427)
    at io.grpc.ForwardingClientCallListener.onClose(ForwardingClientCallListener.java:41)
    at com.coreos.jetcd.internal.impl.ClientConnectionManager$AuthTokenInterceptor$1$1.onClose(ClientConnectionManager.java:267)
    at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:419)
    at io.grpc.internal.ClientCallImpl.access$100(ClientCallImpl.java:60)
    at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.close(ClientCallImpl.java:493)
    at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl.access$500(ClientCallImpl.java:422)
    at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:525)
    at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
    at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:102)
    ... 3 more

我做错了什么，我还能如何将多个 etcd 更改作为原子操作完成？

Answer 1

看起来删除一个键然后为同一个键添加新值的操作不能在同一个txn中。 .根据The etcd APIv3 documentation :

Txn processes multiple requests in a single transaction. A txn request increments the revision of the key-value store and generates events with the same revision for every completed request. It is not allowed to modify the same key several times within one txn.