There are multiple steps to run Lamdba functions locally which connect to a containerized instance of DynamoDB. This tutorial provides complete instructions to accomplish this.
Contact me if you run into problems using this repo or tutorial.
Below is the software you need to install (all instructions for use on a Mac):
If you don't have Python and Homebrew you'll need to get those.
Next, download and install Docker. Once downloaded, run the command docker pull amazon/dynamodb-local to pull the DynamoDB Image - this is provided by AWS and will containerize DynamoDB locally.
Ensure Docker and DynamoDB can run locally by adding your application and dynamodb folders to Docker's File Sharing directories by selecting Preferences from the Docker menu.
My local applications run in the /apps folder so I've added it. You also need to ensure Docker can containerize DynamoDB - I installed DynamoDB in the folder /dynamodb so I provided that location to Docker as well (as pictured above). After making those changes you'll have to select Apply & Restart.
In order to persist data you'll need a folder for the containerized version of DynamoDB to save data. I selected a generic folder of /data (where I also store MongoDB's data) and will pass it as a flag to run a containerized version of DynamoDB.
Once you have all the software downloaded you should be able to run DynamoDB locally using the below command:
docker run -p 8000:8000 -v $(pwd)/local/dynamodb:/data/ amazon/dynamodb-local -jar DynamoDBLocal.jar -sharedDb -dbPath /data.
This terminal window will need to remain open as you use DynamoDB.
Again, notice the -dbPath /data. If you're storing your DynamoDB's data somewhere else you'll need to specify that folder location.
If for any reason the above command doesn't work, you may try a non-persistent containerized version of DynamoDB by running the below command:
docker run -p 8000:8000 amazon/dynamodb-local.
This command will NOT PERSIST DATA. Every time you restart your container (restart Docker, restart your computer) all data will be erased as it is only saved into the container's memory.
Presuming you have DynamoDB running in a Docker container, download and install SAM CLI (Serverless Application Model) if you haven't done so. You may do this by running the command brew tap aws/tap followed by brew install aws-sam-cli - obviously this requires Homebrew. Alternatively, you may download SAM CLI from AWS.
In a new tab, create a table using the below command:
aws dynamodb create-table --table-name Persons --attribute-definitions AttributeName=PersonKey,AttributeType=S --key-schema AttributeName=PersonKey,KeyType=HASH --provisioned-throughput ReadCapacityUnits=1,WriteCapacityUnits=1 --endpoint-url http://localhost:8000
Next - seed your table with a couple records:
aws dynamodb put-item --table-name Persons --item '{ "PersonKey": {"S": "1"}, "FirstName": {"S": "Bill"}, "LastName": {"S": "Smith"} }' --return-consumed-capacity TOTAL --endpoint-url http://localhost:8000
aws dynamodb put-item --table-name Persons --item '{ "PersonKey": {"S": "2"}, "FirstName": {"S": "John"}, "LastName": {"S": "Smith"} }' --return-consumed-capacity TOTAL --endpoint-url http://localhost:8000
In terminal, you may view your table's seeded data by running aws dynamodb scan --table-name Persons --endpoint-url http://localhost:8000
If you've made it this far and data's being returned, you've successfully containerized DynamoDB.
Clone this repo and install the dependencies by running npm install
Run sam local start-api to run your Lambda function and your browser should load with the seeded records from your DynamoDB table.
Pointing your browser to http://localhost:3000 should return records.
Visiting http://localhost:3000/record/1 should return a single record.
You may alternatively run sam local start-api --skip-pull-image if you wish to skip pulling down the latest Docker image for the Lambda runtime.