How to use environment variables in serverless.yml?

Question

Goal:

• create an environment variable with the name of the DynamoDB table and use this variable in the serverless.yml file and in the code also.
• preferably: environment should be created in serverless.yml also.

Solution:

I try to use the environment variable in serverless.yml file in the following way:

• serverless.yml:

provider:
  name: aws
  runtime: java11

  stage: dev
  region: us-east-1

  environment:
    DYNAMO_DB_TABLE: "tableName"

......

resources:
  Resources:

    S3ObjectsTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${DYNAMO_DB_TABLE} /solution1
        TableName: ${env:DYNAMO_DB_TABLE} /solution2


............

• solution1:

With solution1 I receive an error: Member must satisfy regular expression pattern: [a-zA-Z0-9_.-]+

• solution2:

In the documentation, I found several tips, but nothing worked for me, for example:

service: new-service
provider: aws
functions:
  hello:
    name: ${env:FUNC_PREFIX}-hello
    handler: handler.hello
  world:
    name: ${env:FUNC_PREFIX}-world
    handler: handler.world

For my case (solution2) I receive error: Value not found at "env" source

I also tried to create variables in env.yml with useDotenv: true parameter in serverless.yml and other and other else, but nothing works for me.

---

How to correctly create and use environment variables in serverless.yml?

Answer 1

That solution works for me:

I created .env file where I set the needed variables:

DYNAMO_DB_TABLE=s3ObjectsTable
S3_BUCKET_NAME=test-task-files

In this case, I can use them in the serverless.yml and in the project:

service: serverless-task
frameworkVersion: '3'

useDotenv: true

provider:
  name: aws
  runtime: java11

  stage: dev
  region: us-east-1

  environment:
    DYNAMO_DB_TABLE: ${env:DYNAMO_DB_TABLE}
    ....
    enter code here
resources:
  Resources:
    S3Bucket:
      DeletionPolicy: Retain
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${env:S3_BUCKET_NAME}

From the code:

public static String DYNAMO_DB_TABLE_NAME = System.getenv("DYNAMO_DB_TABLE");

Answer 2

You have two possibilities to use dotenv, using this plugin serverless-dotenv-plugin. When you use serverless version 3, you can use dotenv=true