Reset cache in AWS Lambda when AWS Secrets Manager secret value is updated

Question

I am using AWS Secrets Manager for storing secrets and use it in one of my AWS Lambda functions. AWS also provides AWSSDK.SecretsManager.Caching library to improve performance and reduce costs. I also start using it with a long caching lifetime (1 day).

The next step is, when the secret value will be changed, I need to reset the cache immediately.

Now, my question is, how can Lambda be notified that it needs to reset the cache?

Answer 1

You can use AWS Lambda's built-in integration with AWS Secrets Manager to automatically refresh the cached secret value when the value of the secret changes.

Here are the high-level steps to accomplish this:

1. Enable automatic rotation of the secret in AWS Secrets Manager. This will ensure that a new secret value is generated and stored whenever the current secret value expires or is about to expire.

2. Create an AWS Lambda function that uses the cached secret value from AWS Secrets Manager. You can use the AWSSDK.SecretsManager.Caching library to cache the secret value in the Lambda function for improved performance.

3. Configure the AWS Lambda function to use the automatic rotation feature of AWS Secrets Manager. To do this, you can add a trigger to the Lambda function that is triggered by the AWS Secrets Manager secret value change event.

4. When the trigger fires, your Lambda function will receive an event that contains information about the updated secret value. You can use this event to refresh the cached secret value in your Lambda function.

5. After the cached secret value has been updated, you can continue using it in your Lambda function.

Here are the more detailed steps:

1. Enable automatic rotation of the secret in AWS Secrets Manager

To enable automatic rotation of the secret in AWS Secrets Manager, follow these steps:

a. Open the AWS Secrets Manager console.

b. Select the secret that you want to rotate.

c. Click on the "Rotation" tab.

d. Click on the "Edit rotation" button.

e. Select the "Enable automatic rotation" option.

f. Configure the rotation settings according to your requirements.

g. Click on the "Save" button.

1. Create an AWS Lambda function that uses the cached secret value from AWS Secrets Manager

To create an AWS Lambda function that uses the cached secret value from AWS Secrets Manager, follow these steps:

a. Open the AWS Lambda console.

b. Click on the "Create function" button.

c. Select the appropriate runtime and create a new function.

d. Add the code to your function that uses the cached secret value from AWS Secrets Manager. You can use the AWSSDK.SecretsManager.Caching library to cache the secret value in your function.

e. Test your function to ensure that it can use the cached secret value from AWS Secrets Manager.

1. Configure the AWS Lambda function to use the automatic rotation feature of AWS Secrets Manager

To configure the AWS Lambda function to use the automatic rotation feature of AWS Secrets Manager, follow these steps:

a. Open the AWS Lambda console.

b. Select the function that you created in step 2.

c. Click on the "Add trigger" button.

d. Select the "AWS Secrets Manager" option.

e. Select the appropriate secret that you want to monitor for changes.

f. Configure the trigger settings according to your requirements.

g. Click on the "Add" button.

1. Refresh the cached secret value in your Lambda function

When the AWS Secrets Manager secret value changes, the trigger that you added in step 3 will fire and invoke your Lambda function. To refresh the cached secret value in your function, you can use the following code:

using AWSSDK.SecretsManager.Caching;

public async Task FunctionHandler(SQSEvent evnt, ILambdaContext context)
{
    // Get the cached secret value
    var cachedSecret = SecretsManagerCache.GetSecretString("mySecret");

    // Use the cached secret value in your code

    // Refresh the cached secret value if it has expired or has been updated
    var updatedSecret = await SecretsManagerCache.RefreshNowAsync("mySecret");

    // Update the cached secret value in your code
}

Ready to level up your coding game? Uncover the realm of microservices with our cutting-edge Microservices Developer Certification!