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title FAQs
description 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).

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 to adding the aws-crt-client and excluding the aws-crt dependency (contain all runtime libraries) it's required to set a specific runtime version of the aws-crt dependency by specifying the classifier for your specific target runtime. Specifying the specific target runtime makes sure all other target runtimes are excluded from the jar file, which will result in 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>

After configuring the dependencies it's required to specify the aws sdk http client. Most modules support a custom sdk client by leveraging the .withClient() method on the for instance the Provider singleton:

```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.lambda.powertools.parameters.ssm.SSMProvider;

public class RequestHandlerWithParams implements RequestHandler<String, String> {

    // Get an instance of the SSMProvider. We can provide a custom client here if we want,
    // for instance to use the aws crt http client.
    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.