Serverless Framework & Lambda: A Match Made in Heaven

One thing that I have always been keen to get from AWS Lambda is configurable environment variables that can be set for each indivudual Lambda function. One thing I loved about the Serverless framework is that it supports a notion of environment variables, stored in a hidden ‘_meta’ folder and substituted in when the functions are deployed to Lambda.

On our serverless-hipchat-connect project, we added persistence using DynamoDB, a server-less no-SQL database. To create this database, we added it to the `s-resources-cf.json`, such that the required tables would be created as part of a stage’s initialization.

The cool feature in this is that the Serverless Framework can capture the outputs of a CloudFormation template as environment variables for Lambda functions!

"DynamoDBAccessTokenTable": { "Type": "AWS::DynamoDB::Table", "DependsOn": "DynamoDBInstallationTable", "Properties": { "AttributeDefinitions": [ { "AttributeName": "oauthId", "AttributeType": "S" } ], "KeySchema": [ { "AttributeName": "oauthId", "KeyType": "HASH" } ], "ProvisionedThroughput": { "ReadCapacityUnits": 3, "WriteCapacityUnits": 1 } } } }, "Outputs": { "AccessTokenTableName": { "Description": "Name of the AccessTokenTable created by CloudFormation", "Value": { "Ref": "DynamoDBAccessTokenTable" } } }

This can then be referenced in a CloudFormation template’s configuration file:

"environment": { "SERVERLESS_PROJECT": "${project}", "SERVERLESS_STAGE": "${stage}", "SERVERLESS_REGION": "${region}", "ACCESS_TOKEN_TABLE": "${accessTokenTableName}" },

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Originally published at blog.gorillastack.com on May 31, 2016.