How correctly log AWS Lambda event with lambda powertools

Question

I've started using lambda power-tools for lambda. Currently my code looks like:

@event_source(data_class=SNSEvent)
@LOGGER.inject_lambda_context(log_event=True)
def handler(event: SNSEvent, context: LambdaContext) -> None:  # pylint: disable=W0613
    """Lambda function invoked by Image builder SNS topic, putting Image
    builder ami-id in parameter store.
    :param event: SNS message containing Image Builder build results
    :return:
    """
    LOGGER.debug(f"Event: {event}") //logging event
    for record in event.records:
        message = record.sns.message
        LOGGER.info(f"Message: {message}")
        process_sns_event(message)
        return None

In line with comment I want to log what actually is lambda getting at beginning. As for now in cloud watch I'm getting entries like: Event: <aws_lambda_powertools.utilities.data_classes.sns_event.SNSEvent object at 0x7f9bbd36a0> or Event: <generator object SNSEvent.records at 0x7facfb6510> after updating powertools version to latest.<aws_lambda_powertools.utilities.data_classes.event_bridge_event.EventBridgeEvent object at 0x7f8af526d0> for event bridge one.

I'm confused what should I do to log just event json. Can any one point me out what should I do? (I'm rather beginner as can seen).

edit: After update powertools to latest version I'm getting: Event: <generator object SNSEvent.records at 0x7facfb6510>

with logging line line change to: LOGGER.debug(f"Event: {event.records}")

You can also try to set the annotation to str. def(event: ...) -> str: — Erik Asplund, Dec 09 '22 at 07:34

Rhineb · Answer 1 · 2023-08-23T15:21:05.800

I ended up on this post as I was having issues getting powertools to log in JSON format. If someone else ends up here having the same issue it is probably because there is a known issue that shadowJar (shaded jars) dont play nice with the log4j2 from powertools. An additional transformation during the build is required

Using Gradle

import com.github.jengelman.gradle.plugins.shadow.transformers.Log4j2PluginsCacheFileTransformer

shadowJar{
    transform(Log4j2PluginsCacheFileTransformer)
}

Using Maven

<dependencies>
  ...
  <dependency>
    <groupId>com.amazonaws</groupId>
    <artifactId>aws-lambda-java-log4j2</artifactId>
    <version>1.5.1</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.17.1</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.17.1</version>
  </dependency>
  ....
</dependencies>

and add the following transformation

<plugins>
  ...
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <version>2.4.3</version>
    <executions>
      <execution>
        <phase>package</phase>
        <goals>
          <goal>shade</goal>
        </goals>
        <configuration>
          <transformers>
            <transformer
                    implementation="com.github.edwgiz.mavenShadePlugin.log4j2CacheTransformer.PluginsCacheFileTransformer">
            </transformer>
          </transformers>
        </configuration>
      </execution>
    </executions>
    <dependencies>
      <dependency>
        <groupId>com.github.edwgiz</groupId>
        <artifactId>maven-shade-plugin.log4j2-cachefile-transformer</artifactId>
        <version>2.8.1</version>
      </dependency>
    </dependencies>
  </plugin>
  ...
</plugins>

How correctly log AWS Lambda event with lambda powertools

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