# Serverless Config
service: myapp

# Provider
provider:
  name: aws
  runtime: nodejs8.10
  stage: ${opt:stage,'dev'}
  ...

  # Environment Variables
  environment:
    MYSQL_HOST: ${self:custom.mysqlHost.${self:provider.stage}}
    MYSQL_USER: ${self:custom.mysqlUser.${self:provider.stage}}
    MYSQL_PASSWORD: ${self:custom.mysqlPassword.${self:provider.stage}}
    MYSQL_DATABASE: ${self:custom.mysqlDatabase.${self:provider.stage}}
    MYSQL_PORT: ${self:custom.mysqlPort.${self:provider.stage}}

# Custom Variables
custom:
  stages:
    - dev
    - staging
    - prod
  mysqlHost:
    local: localhost
    dev: devdb.example.com
    staging: ${ssm:/myapp/staging/mysql-host} #get from ssm
    prod: ${ssm:/myapp/prod/mysql-host} #get from ssm
  mysqlUser:
    local: root
    dev: myapp_devuser
    staging: myapp_stag
    prod: myapp
  mysqlPassword:
    local: root
    dev: ${ssm:/myapp/dev/mysql-password~true} #get from ssm (secure)
    staging: ${ssm:/myapp/staging/mysql-password~true} #get from ssm (secure)
    prod: ${ssm:/myapp/prod/mysql-password~true} #get from ssm (secure)
  mysqlDatabase:
    local: myapp_testdb
    dev: myapp_dev
    staging: myapp_staging
    prod: myapp_prod
  mysqlPort:
    local: '8889'
    dev: '3306'
    staging: '3306'
    prod: '3306'

# Plugins
plugins:
  - serverless-stage-manager

...