Development, staging and prod environments

Serverless Framework
1

Hi!
I’ve done small serverless app using Serverless framework and AWS.
And I’m wondering what is proper way to distinguish environment settings for development (verification), staging and prod environments. I have separate AWS accounts for environments (company requirment)
I have ENV for DB connection to RDS, ARN for AWS Cognito, SG and subnets to distinguish between environments.
Would appreciate any advises on how to do that.

2

Hi @kukula! I recommend handling this with different JSON config files for each environment. You can then tell Serverless which config file to use based on the stage.

For example, let’s say I have an environment variable called DB_CONN that is my db connection string. I want this to vary across dev, staging, and prod environments. I’d set my serverless.yml with:

# serverless.yml

custom:
  defaultStage: dev
  currentStage: ${opt:stage, self:custom.defaultStage} # 'dev' is default unless overriden by --stage flag


provider:
  name: aws
  runtime: nodejs6.10
  stage: ${self:custom.currentStage}
  environment:
      DB_CONN: ${file(./config.${self:custom.currentStage}.json):DB_CONN}

In the custom block, I’m setting up my stage. My default stage is dev, but I can override it by passing a --stage variable at the command line.

Note the DB_CONN line in the environments section – It pulls the DB_CONN value from a file named config.<stage>.json. Now, I can have three different files in my repository:

# config.dev.json
{
    "DB_CONN": "<db_connection_string_for_dev>"
}

# config.staging.json
{
    "DB_CONN": "<db_connection_string_for_staging>"
}

# config.prod.json
{
    "DB_CONN": "<db_connection_string_for_prod>"
}

Let me know if this works for you!

1 Like
3

Thank you for advise alexdebrie1!
What it is best practice with a listed settings like securityGroupIds and subnetIds?

4

You’re welcome, @kukula!

For lists, you can use an array in your JSON:

# serverless.yml

provider:
  name: aws
  .... <other config settings>...
  vpc:
    securityGroupIds: ${file(./config.$self:custom.currentStage}.json):SECURITY_GROUP_IDS}
    subnetIds: ${file(./config.$self:custom.currentStage}.json):SUBNET_IDS}

# config.prod.json
{
  "SECURITY_GROUP_IDS": ["securityGroupId1", "securityGroupId2"],
  "SUBNET_IDS": ["subnetId1", "subnetId2"]
}

Note that you could also make your config file in YML if it’s easier to write in yml for both your serverless.yml file and your config.prod.yml file:

# config.prod.yml

securityGroupIds:
  - securityGroupId1
  - securityGroupId2
subnetIds:
  - subnetId1
  - subnetId2

Just make sure you’re referencing the proper file name and property within the file.