sam deploy should accept parameter file just like aws cloudformation *-stack

Description:

I would like to store configuration is version control and make deployment steps immutable. Instead of changing parameter overrides on the command line I would like to provide template parameters from a file.

There is an idiom for this in aws cloudformation create-stack --parameters file://.

Steps to reproduce the issue:

1. sam deploy --parameter-overrides file://params.json

Observed result:

Error: Invalid value for '--parameter-overrides':  file://params.json is not in valid format. It must look something like 'ParameterKey=KeyPairName,ParameterValue=MyKey ParameterKey=InstanceType,ParameterValue=t1.micro' or 'KeyPairName=MyKey InstanceType=t1.micro'

Expected result:

	Deploying with following values
	===============================
	Stack name                 : ...
	Region                     : ...
	Confirm changeset          : ...
	Deployment s3 bucket       : ...
	Capabilities               : ...
	Parameter overrides        : {'MyParamOverride': 'MyParamValue'}

[jveldboom]

We use a similar pattern to @rojomisin but use a standard environment variable file format.

.sam-params

DBUsername=admin
DBPassword=password123
Subnets=subnet-12345
VpcId=vpc-1234

Then in our Makefile, we cat that file and pass them in as --parameter-overrides

sam deploy --parameter-overrides $(shell cat .sam-params)

[HFR1994]

I’m using jq as an alternative… Having the following structure

// parameters.json

[
  {
    "ParameterKey": "ApplicationName",
    "ParameterValue": "Foo"
  },
  {
    "ParameterKey": "ApplicationKey",
    "ParameterValue": "Bar"
  }
]

I can do

SAM_PARAMETERS=$( cat ${DIR}/parameters.json | jq -r '.[] | "\(.ParameterKey)=\(.ParameterValue)"' )
sam deploy ... --parameter-overrides $SAM_PARAMETERS

The good thing is that file can be shared with Cloudformation templates with:

aws cloudformation deploy ... --parameter-overrides "file://${DIR}/parameters.json"