Add Braintree settings to Commerce Engine image

Dockerfile

ARG BASE_IMAGE
FROM $BASE_IMAGE

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop';"]
ARG BRAINTREE_ENVIRONMENT
ARG BRAINTREE_MERCHANT_ID
ARG BRAINTREE_PUBLIC_KEY
ARG BRAINTREE_PRIVATE_KEY
RUN $json = Get-Content "C:\inetpub\wwwroot\wwwroot\data\Environments\PlugIn.Payments.Braintree.PolicySet-1.0.0.json" | ConvertFrom-Json; \
$json.Policies.'$values'[0].Environment = $env:BRAINTREE_ENVIRONMENT; \
$json.Policies.'$values'[0].MerchantId = $env:BRAINTREE_MERCHANT_ID; \
$json.Policies.'$values'[0].PublicKey = $env:BRAINTREE_PUBLIC_KEY; \
$json.Policies.'$values'[0].PrivateKey = $env:BRAINTREE_PRIVATE_KEY; \
$json | ConvertTo-Json -Depth 32 | Set-Content "C:\inetpub\wwwroot\wwwroot\data\Environments\PlugIn.Payments.Braintree.PolicySet-1.0.0.json"

Create an image with Braintree settings added.

Not yet working... Still working on proper syntax for the ARG values when referenced in Powershell. 😕

The gist works now. The original issue was the placement of the ARG commands, which go out of scope after the following command, as noted in the Dockerfile documentation:

An ARG instruction goes out of scope at the end of the build stage where it was defined. To use an arg in multiple stages, each stage must include the ARG instruction.
https://docs.docker.com/engine/reference/builder/