Docker-Compose Multiline Key - docker-compose

Question

How do I define a multiline key in docker-compose.yml?
I tried diff solutions:
environment:
- PRIVATE_KEY= |-
-----BEGIN RSA PRIVATE KEY-----
line2
environment:
- PRIVATE_KEY= |
-----BEGIN RSA PRIVATE KEY-----
line2
environment:
- PRIVATE_KEY= !
-----BEGIN RSA PRIVATE KEY-----
line2
environment:
- PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\nline2"
environment:
- PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\n\nline2"
Resources:
https://yaml-multiline.info/
https://gist.github.com/usmansaleem/bb47064f406c105fdfa69716544b7b8e
But none of them formatted the private key in a proper way.
Edit (Addition):
environment:
- PRIVATE_KEY: |-
-----BEGIN RSA PRIVATE KEY-----
line2

Answer 1

The only key in your "test" document is the scalar environment, the other scalars are all unquoted multi-line scalar values.
You refer to a document that explains how to do literal scalars, but you never try those, as this
- PRIVATE_KEY= |-
-----BEGIN RSA PRIVATE KEY-----
line2
is the same as doing
- PRIVATE_KEY= |- -----BEGIN RSA PRIVATE KEY----- line2
i.e. the |- doesn't have any special function except at the beginning of a scalar.
Did you try to do:
PRIVATE_KEY: |-
-----BEGIN RSA PRIVATE KEY-----
line2
that would be a key value pair (note the value indicator (:) instead of the normal character =), with the value being a block style literal scalar

Answer 2

Try using > this solution works pretty well if you need to have a json in your env variables. There are many ways to have a multiline strings in YAML.
version: '2'
services:
catalog-api-autoscaling:
image: company.it/project/catalog-api-autoscaling:latest
container_name: api-autoscaling
ports:
- "8083:8083"
environment:
CONFIG_ABC: >
{
"database": {
"catalog": {
"credentials": {
"username": "scott",
"password": "tiger",
"datbase": "catalog",
"host": "gn.dmfkd.lan"
}
}
}
}
CONFIG_DEF: >
{
"urlRegex": "/.*",
"script": {
"scriptPath": "example-python-app.py"
},
"runtime": "python27",
"threadsafe": true,
}