How to inject environment variables in elastic beanstalk config.yml - amazon-web-services

Question

In the link below
http://docs.shippable.com/deploy/aws-elastic-beanstalk/
it seems like environment variables are used in config.yml . How do we achieve that? It seems like official documentation of aws does not have details on using variables inside config.yml.
Any suggestions will be of great help.
I am looking to set something like
default_platform using env variables and not application variables alone.

Answer 1

Yes, you won't find anything in AWS documentation because using environment variables for templating the config.yml is a Shippable feature not an AWS feature.
Shippable details how to add extra ENVs (environment variables) in the documentation you posted:
Which reads (highlighted in bold):
Define deploy-eb-basic-params
Description: deploy-eb-basic-params is a params resource that defines variables we want to make easily configurable. These variables definitions replace the placeholders in the Dockerrun.aws.json and config.yml files.
Steps:
Add the following yml block to the resources section in your shippable.yml file.
# shippable.yml
resources:
- name: deploy-eb-basic-params
type: params
version:
params:
ENVIRONMENT: "sample"
PORT: 80
AWS_EB_ENVIRONMENT_SINGLE: "Sample-env"
AWS_EB_APPLICATION: "deploy-eb-basic"
CUSTOM_ENV_HERE: "some value" # <------------ your custom value here.
Then you should be able to reference that ENV CUSTOM_ENV_HERE in your config.yml
# config.yml
branch-defaults:
default:
environment: ${AWS_EB_ENVIRONMENT_SINGLE}
environment-defaults:
${AWS_EB_ENVIRONMENT_SINGLE}:
branch: null
repository: null
global:
application_name: ${AWS_EB_APPLICATION}
default_ec2_keyname: null
default_platform: ${CUSTOM_ENV_HERE} # <------------ you reference ENV here.
default_region: ${DEPLOYEBBASICCONFIG_POINTER_REGION}
instance_profile: null
platform_name: null
platform_version: null
profile: null
sc: null
workspace_type: Application
Best of luck.