如何以编程方式启动本地DynamoDB？ [英] How to launch local DynamoDB programmatically?

问题描述

我可以通过以下命令从bash启动 local DynamoDB服务器：

I am able to launch a local DynamoDB server from bash through this command:

java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb &

是否没有一种纯Java的方法即可通过自己的代码启动服务器？我的意思不是通过 Process 对象对外壳程序进行java调用，而是这样一种方式：当我运行我的应用程序时，服务器启动，而当我的应用程序被终止时，

Is there not a pure-java way to start the server in one's code? I don't mean a java callout to the shell through the Process object but a way such that when I run my app, the server starts, and when my app is killed, the server is killed.

如果存在这种模式，我可以使用嵌入式数据库，尽管反映服务器一致性语义的方法是理想的。

I can live with an embedded database if such a mode exists, though something that reflects server consistency semantics would be ideal.

推荐答案

编辑：2015年9月23日

2015年8月3日上有一条公告，该公告现在添加了能够在同一进程中运行嵌入式DynamoDB本地。您可以添加Maven测试依赖项并使用以下方式之一运行它。

There was an announcement on Aug 3, 2015 that now adds the ability to have an embedded DynamoDB local running in the same process. You can add a Maven test dependency and use one of the ways below to run it.

<!--Dependency:-->
<dependencies>
    <dependency>
       <groupId>com.amazonaws</groupId>
       <artifactId>DynamoDBLocal</artifactId>
       <version>[1.11,2.0)</version>
    </dependency>
</dependencies>
<!--Custom repository:-->
<repositories>
    <repository>
       <id>dynamodb-local-oregon</id>
       <name>DynamoDB Local Release Repository</name>
       <url>https://s3-us-west-2.amazonaws.com/dynamodb-local/release</url>
    </repository>
</repositories>

这是从 awslabs / aws-dynamodb-examples Github存储库：

And here is an example taken from the awslabs/aws-dynamodb-examples Github repository:

AmazonDynamoDB dynamodb = null;
try {
    // Create an in-memory and in-process instance of DynamoDB Local that skips HTTP
    dynamodb = DynamoDBEmbedded.create().amazonDynamoDB();
    // use the DynamoDB API with DynamoDBEmbedded
    listTables(dynamodb.listTables(), "DynamoDB Embedded");
} finally {
    // Shutdown the thread pools in DynamoDB Local / Embedded
    if(dynamodb != null) {
        dynamodb.shutdown();
    }
}

// Create an in-memory and in-process instance of DynamoDB Local that runs over HTTP
final String[] localArgs = { "-inMemory" };
DynamoDBProxyServer server = null;
try {
    server = ServerRunner.createServerFromCommandLineArgs(localArgs);
    server.start();

    dynamodb = AmazonDynamoDBClientBuilder.standard().withEndpointConfiguration(
        // we can use any region here
        new AwsClientBuilder.EndpointConfiguration("http://localhost:8000", "us-west-2"))
        .build();

    // use the DynamoDB API over HTTP
    listTables(dynamodb.listTables(), "DynamoDB Local over HTTP");
} finally {
    // Stop the DynamoDB Local endpoint
    if(server != null) {
        server.stop();
    }
}

---

旧答案

就像您说的那样，DynamoDBLocal或SDK目前没有内置方法可以立即执行此操作。如果有一个嵌入式DynamoDBLocal，可以在同一过程中启动，那就太好了。

Like you said, there is currently no built-in way from DynamoDBLocal or the SDK to do this right now. It would be nice if there was an embedded DynamoDBLocal that you could start up in the same process.

这里是使用 java.lang.Process 启动它，并以编程方式关闭它，以防其他人感兴趣。

Here is a simple workaround/solution using java.lang.Process to start it up and shut it down programmatically in case others are interested.

DynamoDBLocal的文档可以找到这里和这里是参数的当前定义：

Documentation for DynamoDBLocal can be found here and here are the current definition of the arguments:

• - inMemory —在内存中运行，没有文件转储


• -端口4000 —使用端口4000进行通信。 / li>
  
• -sharedDb —使用单个数据库文件，而不是每个凭据和区域使用单独的文件

• -inMemory — Run in memory, no file dump
• -port 4000 — Communicate using port 4000.
• -sharedDb — Use a single database file, instead of separate files for each credential and region

请注意，这使用的是DynamoDBLocal的最新版本，截至2015年8月5日。。

final ProcessBuilder processBuilder = new ProcessBuilder("java",
        "-Djava.library.path=./DynamoDBLocal_lib",
        "-jar",
        "DynamoDBLocal.jar",
        "-sharedDb",
        "-inMemory",
        "-port",
        "4000")
        .inheritIO()
        .directory(new File("/path/to/dynamo/db/local"));

final Process process = processBuilder.start();

Runtime.getRuntime().addShutdownHook(new Thread() {
    @Override
    public void run() {
        System.out.println("Shutdown DynamoDBLocal");
        process.destroy();
        try {
            process.waitFor(3, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            System.out.println("Process did not terminate after 3 seconds.");
        }
        System.out.println("DynamoDBLocal isAlive=" + process.isAlive());
    }
});
// Do some stuff

这篇关于如何以编程方式启动本地DynamoDB？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！