How to Run and Test AWS Lambda Function Using Docker in Your Laptop

Cong Pham
Geek Culture
Published in
4 min readAug 8, 2022


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AWS Lambda is a serverless computing service, which allows developers to build and run applications without having to manage servers, provided by Amazon Web Service.

There are several ways to write and test AWS Lambda. We can write our code directly in the AWS Lambda console, or we can write our code in our laptop, build it and then upload the build package to AWS Lambda console and test it there. Both ways require us to have the AWS account and access to AWS Lambda console, which can be very inconvenient and expensive especially for an organization with many engineers. Therefore, using Docker container to run and test code locally could help eliminate the need for accessing to the AWS Lambda console, in return reducing the cost and development time.

Lambda supports multiple programming language, we’ll use Java as an example in this article.

Step 1) Install Maven

Some IDEs usually have Maven as plugin, I am using Visual Studio code(VSC) with Maven plugin. For more info on how to install Maven, you can visit the link provided by the VSC’s team.

Step 2) Create the project folder and Generate the Maven code template

To create the project folder, we run this command in our terminal

mkdir hello-lambda

To generate a Maven project, open the Command Palette in VSC and search for Create Java Project command.

Let’s keep everything else default after that.

This is what the project folder should look like after finishing step 2.

Step 3) Add AWS dependencies and packaging plugins

The AWS SDK allows us to write lambda handler code that lambda function can read. Packaging plugins help us to package our code into a build file that can be run in the Docker container.

To add AWS dependencies to our project, we go to the pom.xml file and add these dependencies under dependencies tag.

To add plugin packaging, in the pom.xml file and add these plugins under plugins tag.

Step 4) Add example Lambda code

Add an file in the same directory of the .

This file serves as an input object to our lambda function. Then, add the below code to the .

In the folder, we can add simple Java code such as

This lambda code receives the Input object and response with Hello <input payload string>.

Step 5) Build and Package our code

In our terminal, jump into demo folder and run

mvn compile dependency:copy-dependencies -DincludeScope=runtime

This command generates a target folder with classes and dependency folders inside.

Step 6) Run and Test our code in Docker Container

In the demo folder, add a Dockerfile

Then copy the content of the following to our Dockerfile.

Basically, what this Dockerfile does is that it is using lambda runtime image from AWS for Java 11. Then it copies the classes and dependency that we generated earlier in the target folder into the lambda working directory of the Docker container. Finally, it specifies where our Java code is for the command handler to run.

Now we are ready to build and run our code in the Docker container. Run these two commands. (make sure that you installed Docker and docker is running in the background)

docker build -t lambdacode .

docker run -p 9000:8080 lambdacode

Once it is run, our terminal output should look similar

08 Aug 2022 02:54:36,830 [INFO] (rapid) exec '/var/runtime/bootstrap' (cwd=/var/task, handler=)

and we won’t be able to type new command as the Docker container is running our lambda code in the current terminal.

Then, create a second terminal and run the following command

curl -XPOST “http://localhost:9000/2015-03-31/functions/function/invocations" -d ‘{“payload”:”Lambda”}’

This command provides our lambda function with the payload input string Lambda and we will see the result Hello Lambda. We can replace "Lambda" with anything for testing.

We have run our lambda function using Docker and without uploading it to AWS console. Congrats!



Cong Pham
Geek Culture

Hi! My name is Cong from Calgary, Canada. I have a Bachelor degree in Software Engineering and I am trying to share everything I know with you guys :)