Docker build failed: tag invalid reference format (Gitlab CI)

Question

I've created a repo in gitlab for a Dockerfile. In the .gitlab-ci.yml i defined two stages: build and push to the registry.

This is the .gitlab-ci.yml file:

image: docker

stages:
    - build
    - push

build:
    stage: build
    script:
      - docker build --no-cache -t ${DOCKER_REGISTRY}/debian9-cunit .

push:
    stage: push
    script:
      - docker push ${DOCKER_REGISTRY}/debian9-cunit

When I run the pipeline, the build stage fails saying:

invalid argument "/debian9-cunit" for "-t, --tag" flag: invalid reference format

The same exact code (with only a different name after "/debian9-") works with no problem in another repo of a collegue. What can be the problem?

Seems the ${DOCKER_REGISTRY} variable is not replaced, perhaps the pipeline is looking into system variables. could you try to add double quotes in the script section? — M. Falzone
I tried both "${DOCKER_REGISTRY}/debian9-cunit" and "${DOCKER_REGISTRY}"/debian9-cunit but the result is the same — Federico Taschin
Try replacing ${DOCKER_REGISTRY} with an actual existing repository. I agree with @M.Falzone, seems like that variable isn't set, and Docker is yelling because you can't start your tag with a slash. — bluescores
is it possible that DOCKER_REGISTRY isn't setted up? btw seems you want to use the gitlab.com registry, in that case, try with "docker build --no-cache -t ${CI_REGISTRY}/${CI_PROJECT_PATH}/debian-9-cunit ." — M. Falzone
If I replace with ${CI_REGISTRY}/${CI_PROJECT_PATH}/debian-9-cunit I get: "invalid argument "/federico/dk-debian9-cunit/debian9-cunit" for "-t, --tag" flag: invalid reference format" — Federico Taschin

Michael Plainer Michael Plainer · Accepted Answer · 2019-08-30T15:59:19

If anyone is having this issue in combination with Heroku-based applications (e.g. in Gitlab AutoDevOps) you might need to activate the GitLab container registry on your GitLab installation and in your project.

Docker build failed: tag invalid reference format (Gitlab CI)

2 Answers