IAM

2. Create an IAM Role for Your Lambda Function

Background

Every Lambda function has an IAM role associated with it. This role defines what other AWS services the function is allowed to interact with. For the purposes of this workshop, you’ll need to create an IAM role that grants your Lambda function permission to write logs to Amazon CloudWatch Logs and access to write items to your DynamoDB table.

High-Level Instructions

Use the IAM console to create a new role. Name it WildRydesLambda and select AWS Lambda for the role type. You’ll need to attach policies that grant your function permissions to write to Amazon CloudWatch Logs and put items to your DynamoDB table.

Attach the managed policy called AWSLambdaBasicExecutionRole to this role to grant the necessary CloudWatch Logs permissions. Also, create a custom inline policy for your role that allows the ddb:PutItem action for the table you created in the previous section.

✅ Step-by-step directions

  1. Go to the AWS IAM Console
  2. Select Roles in the left navigation bar and then choose Create role.
  3. Select Lambda for the role type from the AWS service group, then click Next: Permissions Note: Selecting a role type automatically creates a trust policy for your role that allows AWS services to assume this role on your behalf. If you were creating this role using the CLI, AWS CloudFormation or another mechanism, you would specify a trust policy directly.
  4. Begin typing AWSLambdaBasicExecutionRole in the Filter text box and check the box next to that role.
  5. Click Next: Tags. Add any tags that you wish.
  6. Click Next: Review.
  7. Enter WildRydesLambda for the Role name.
  8. Choose Create role.

Next you need to add permissions to the role so that it can access your DynamoDB table.

*✅ Step-by-step directions

  1. While in the IAM Console on the roles page type WildRydesLambda into the filter box on the Roles page and choose the role you just created.
  2. On the Permissions tab, choose the Add inline policy link in the lower right corner to create a new inline policy. Inline policies screenshot
  3. Select Choose a service.
  4. Begin typing DynamoDB into the search box labeled Find a service and select DynamoDB when it appears. Select policy service
  5. Choose Select actions.
  6. Begin typing PutItem into the search box labeled Filter actions and check the box next to PutItem when it appears.
  7. Select the Resources section.
  8. With the Specific option selected, choose the Add ARN link in the table section.
  9. Paste the ARN of the table you created in the previous section in the Specify ARN for table field, and choose Add.
  10. Choose Review Policy.
  11. Enter DynamoDBWriteAccess for the policy name and choose Create policy. Review Policy