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title description
FAQs
Frequently Asked Questions

How can I use Powertools for AWS Lambda (Java) with Lombok?

Powertools uses aspectj-maven-plugin to compile-time weave (CTW) aspects into the project. In case you want to use Lombok or other compile-time preprocessor for your project, it is required to change aspectj-maven-plugin configuration to enable in-place weaving feature. Otherwise the plugin will ignore changes introduced by Lombok and will use .java files as a source.

To enable in-place weaving feature you need to use following aspectj-maven-plugin configuration:

<configuration>
    <forceAjcCompile>true</forceAjcCompile> 
    <sources/>
    <weaveDirectories>
        <weaveDirectory>${project.build.directory}/classes</weaveDirectory>
    </weaveDirectories>
    ...
    <aspectLibraries>
        <aspectLibrary>
            <groupId>software.amazon.lambda</groupId>
            <artifactId>powertools-logging</artifactId>
        </aspectLibrary>
    </aspectLibraries>
</configuration>

How can I use Powertools for AWS Lambda (Java) with Kotlin projects?

Powertools uses aspectj-maven-plugin to compile-time weave (CTW) aspects into the project. When using it with Kotlin projects, it is required to forceAjcCompile. No explicit configuration should be required for gradle projects.

To enable forceAjcCompile you need to use following aspectj-maven-plugin configuration:

<configuration>
    <forceAjcCompile>true</forceAjcCompile> 
    ...
    <aspectLibraries>
        <aspectLibrary>
            <groupId>software.amazon.lambda</groupId>
            <artifactId>powertools-logging</artifactId>
        </aspectLibrary>
    </aspectLibraries>
</configuration>

How can I use Powertools for AWS Lambda (Java) with the AWS CRT HTTP Client?

Powertools uses the url-connection-client as the default http client. The url-connection-client is a lightweight http client, which keeps the impact on Lambda cold starts to a minimum. With the announcement of the aws-crt-client a new http client has been released, which offers faster SDK startup time and smaller memory footprint.

Unfortunately, replacing the url-connection-client dependency with the aws-crt-client will not immediately improve the lambda cold start performance and memory footprint, as the default version of the dependency contains low level libraries for all target runtimes (Linux, MacOS, Windows, etc).

Configuring dependencies

Using the aws-crt-client in your project requires the exclusion of the url-connection-client transitive dependency from the powertools dependency.

<dependency>
    <groupId>software.amazon.lambda</groupId>
    <artifactId>powertools-parameters</artifactId>
    <version>1.18.0</version>
    <exclusions>
        <exclusion>
            <groupId>software.amazon.awssdk</groupId>
            <artifactId>url-connection-client</artifactId>
        </exclusion>
    </exclusions>
</dependency>

Next, add the aws-crt-client and exclude the "generic" aws-crt dependency (contains all runtime libraries). Instead, set a specific classifier of the aws-crt to use the one for your target runtime: either linux-x86_64 for a Lambda configured for x86 or linux-aarch_64 for Lambda using arm64. By specifying the specific target runtime, it will avoid other target runtimes to be included in the jar file, which will result in a smaller Lambda package and the benefit of improved cold start times.

<dependencies>
    <dependency>
        <groupId>software.amazon.awssdk</groupId>
        <artifactId>aws-crt-client</artifactId>
        <version>2.23.21</version>
        <exclusions>
            <exclusion>
                <groupId>software.amazon.awssdk.crt</groupId>
                <artifactId>aws-crt</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

    <dependency>
        <groupId>software.amazon.awssdk.crt</groupId>
        <artifactId>aws-crt</artifactId>
        <version>0.29.9</version>
        <classifier>linux-x86_64</classifier>
    </dependency>
</dependencies>

Explicitly set the AWS CRT HTTP Client

After configuring the dependencies, it's required to explicitly specify the AWS SDK http client. Depending on the Powertools module, there is a different way to configure the sdk client.

The following example shows how to use the Lambda Powertools Parameters module while leveraging the AWS CRT Client.

```java hl_lines="11-16 19-20 22"
import static software.amazon.lambda.powertools.parameters.transform.Transformer.base64;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;
import software.amazon.awssdk.services.ssm.SsmClient;
import software.amazon.awssdk.http.crt.AwsCrtHttpClient;
import software.amazon.lambda.powertools.parameters.ssm.SSMProvider;

public class RequestHandlerWithParams implements RequestHandler<String, String> {

    // Get an instance of the SSMProvider with a custom HTTP client (aws crt).
    SSMProvider ssmProvider = SSMProvider
            .builder()
            .withClient(
                    SsmClient.builder()
                            .httpClient(AwsCrtHttpClient.builder().build())
                            .build()
            )
            .build();

    public String handleRequest(String input, Context context) {
        // Retrieve a single param
        String value = ssmProvider
                .get("/my/secret");
                // We might instead want to retrieve multiple parameters at once, returning a Map of key/value pairs
                // .getMultiple("/my/secret/path");

        // Return the result
        return value;
    }
}
```

It has been considered to make the aws-crt-client the default http client in Lambda Powertools for Java, as mentioned in Move SDK http client to CRT, but due to the impact on the developer experience it was decided to stick with the url-connection-client.