How to create a release tag using .gitlab-ci.yml file - tags

Question

I neet to run jobB only when jobA passes. I have to create a release tag only when my test stage passes successfully (I have added a code for that to happen here). My repository has 'README.md' file already. I am just checking its existence in my test stage. So, my test stage will always pass. Please let me know how do I write a code to create a release tag. A tag can be for example v1.1
stages:
- build
- test
- release
jobA:
stage: test
script:
- test -e README.md && exit 0
jobB:
stage: release
when: on_success
script:
# code for creating a release tag

Answer 1

In addition of Greg Woz's answer, in which GITLAB_API_TOKEN (a PAT -- PErsonal Access Token) is used, you now can also use a dedicated private project token:
See GitLab 13.9 (February 2021)
Support PRIVATE-TOKEN to create releases using the Release-CLI
In this milestone, we added the ability to use the release-cli with a PRIVATE-TOKEN as defined in the Create a release API documentation.
This enables overriding the user that creates a release, and supports automation by allowing connection of a project-level PRIVATE-TOKEN or by using a bot user account’s PRIVATE-TOKEN.
See Documentation and Issue.

Answer 2

It may not answer fully for your question but hopefully it helps. Perhaps try the below. My solution assumes you have package.json with version as it's the most popular case - but there is nothing wrong if you use any other way to define version:
version:
stage: version
only:
- master
script:
- VERSION_NUMBER=$(node -p "require('./package.json').version")
- "curl --header \"PRIVATE-TOKEN: $GITLAB_API_TOKEN\" --request POST \"https://gitlab.com/api/v4/projects/$CI_PROJECT_ID/repository/tags?tag_name=v${VERSION_NUMBER}&ref=$CI_COMMIT_SHA&message=Tagged%20with%20version%20v${VERSION_NUMBER}\""
Then you can use:
publish:
stage: publish
only:
- tags
script:
- npm version --no-git-tag-version ${CI_COMMIT_TAG:1}
- npm publish --access public
for example in a next step.

Answer 3

Gitlab 13.2 introduced release keyword in .gitlab-ci.yml. There's no need anymore to create a "jobB" job, you can add keyword to main job as long as it can access release-cli:
stages:
- build
- test
- release
jobA:
stage: test
image: registry.gitlab.com/gitlab-org/release-cli:latest
script:
- test -e README.md && exit 0
release:
tag_name: $TAG
description: './path/to/CHANGELOG.md'
GitLab Docs has some examples to dynamically provide $TAG and description.

Answer 4

Probably the dependencies mechanism is a right tool for doing that. So, you can use README.MD (or test results folder) as an artifact in jobA and add the dependency on jobA in the jobB
jobB:
....
dependencies:
- jobA
If the jobA fail it won't provide dependent artifact for jobB. Thus, it also will fail.
(Edit)
Have you checked Protected tags gitlab settings? (Settings -> Repository -> Protected tags)
Default settings are:
By default, protected tags are designed to:
Prevent tag creation by everybody except Maintainers
Prevent anyone from updating the tag
Prevent anyone from deleting the tag