Using sed from Makefile - makefile

Question

In a Makefile I'm trying to do the following:
Here I'm getting a couple things I need:
S3_BUCKET_NAME_STATE=$(shell terraform output -json | jq '.S3_Bucket.value')
DYNAMODB_LOCK=$(shell terraform output -json | jq '.dynamo_db_lock.value')
And with the result of that (i.e.: the content in the variables) I want to do some replacements in a file, like this:
sed 's/{{ BUCKET_NAME }}/$$(S3_BUCKET_NAME_STATE)/g;' variables.tf.template > variables.tf)
But it keeps on not doing it right. I've tried using ${} instead but i can't make it work...
Help is appreciated!

Answer 1

You didn't mention whether these are make variables or shell variables, so I'm going to assume they're make variables.
Here's a working example of how to do this. It has 3 files: test.json, variables.tf.template, and Makefile.
Makefile:
S3_BUCKET_NAME_STATE := $(shell cat test.json | jq -r '.S3_Bucket.value')
all:
sed 's/{{ BUCKET_NAME }}/$(S3_BUCKET_NAME_STATE)/g;' variables.tf.template > variables.tf
test.json:
{"S3_Bucket": {"value": "Foo"}}
variables.tf.template:
some stuff {{ BUCKET_NAME }}
I made the following changes:
Using := instead of =. The equals operator is the lazy substitution operator, which expands the macro at the time that it's used rather than at the time of defintion.
Using -r with jq. This gets the raw string value.
Using $(var) instead of $$(var). Make interprets a double dollar sign as an escaped dollar sign.
I tested this on GNU Make 3.81 and 4.3.