Is it possible to use a here-document from within a multiline command in .gitlab-ci.yml? - gitlab

Question

Is it possible to use a here-document from within a multiline command in .gitlab-ci.yml
I am having difficulty using a here-document within a command that expands multiple lines in a .gitlab-ci.yml job. For example I have created a short test job below, that uses a here-document to assign a multiline string to an environment variable PAYLOAD that is then used in a curl request to POST data to a url:
example:
image: node:12-stretch-slim
stage: mystage
script:
- >
PAYLOAD=$(cat << 'JSON'
'{
"branch": "master",
"commit_message": "some commit message",
"actions": [
{
"action": "create",
"file_path": "foo/bar",
"content": "some content"
}
]
}'
JSON
)
- >
curl -X POST https://requestbin.io/1f84by61
--header 'Content-Type: application/json; charset=utf-8'
--data-binary "$PAYLOAD"
when: manual
only:
- /^release-.*$/
The following script fails with the following message on gitlab.com CI server:
$ PAYLOAD=$(cat << 'JSON' '{ # collapsed multi-line command
[551](<private url>) /bin/bash: line 140: warning: here-document at line 140 delimited by end-of-file (wanted `JSON')
[552](<private url>) /bin/bash: line 139: warning: here-document at line 139 delimited by end-of-file (wanted `JSON')
[553](<private url>) cat: '{'$'\n'' "branch": "master",'$'\n'' "commit_message": "some commit message",'$'\n'' "actions": ['$'\n'' {'$'\n'' "action": "create",'$'\n'' "file_path": "foo/bar",'$'\n'' "content": "some content"'$'\n'' }'$'\n'' ]'$'\n''}': No such file or directory
[554](<private url>) cat: JSON: No such file or directory
Can anyone help?

Answer 1

Solved it after reading this
Using |- preserves newlines within the command and does not append a newline at the end of the command string. Beforehand I was using > which replaces newlines in the command string with spaces.
release:
image: node:12-stretch-slim
stage: release
before_script:
- apt-get update && apt-get install -y curl git jq
script:
- |-
PAYLOAD=$(cat << JSON
{
"branch": "master",
"commit_message": "some commit message",
"actions": [
{
"action": "create",
"file_path": "foo/bar",
"content": "some content"
}
]
}
JSON
)
- >
curl -X POST https://requestbin.io/1f84by61
--header 'Content-Type: application/json; charset=utf-8'
--data-binary "$PAYLOAD"
when: manual
only:
- /^release-.*$/