Improve Makefile variables for GitLab and set defaults

.gitlab-ci.yml

@@ -5,10 +5,6 @@ image: docker:latest
 services:
   - docker:dind
 
-variables:
-  DOCKER_REGISTRY: ${CI_REGISTRY}
-  DOCKER_IMAGE_PREFIX: ${CI_PROJECT_PATH}/
-
 before_script:
   - docker info
   - docker login -u gitlab-ci-token -p ${CI_JOB_TOKEN} ${CI_REGISTRY}

Makefile

-IMAGE_PREFIX := ${DOCKER_IMAGE_PREFIX}
-ifeq ($(IMAGE_PREFIX),)
-IMAGE_PREFIX := icinga/raspbian-base
+ifndef CI_REGISTRY
+CI_REGISTRY := registry.icinga.com
 endif
-
-REGISTRY := ${DOCKER_REGISTRY}
-ifneq ($(REGISTRY),)
-IMAGE_PREFIX := $(REGISTRY)/$(IMAGE_PREFIX)
+ifeq ($(CI_PROJECT_PATH),)
+CI_PROJECT_PATH := build-docker/raspbian
+endif
+ifeq ($(CI_COMMIT_REF_NAME),)
+CI_COMMIT_REF_NAME := $(shell git rev-parse --abbrev-ref HEAD)
 endif
 
 FROM := $(shell grep FROM Dockerfile | cut -d" " -f2)
-IMAGE := $(IMAGE_PREFIX)debootstrap
+IMAGE := $(CI_PROJECT_PATH)/${CI_COMMIT_REF_NAME}
+
+ifneq ($(CI_REGISTRY),)
+IMAGE := $(CI_REGISTRY)/$(IMAGE)
+endif
 
 QEMU_VERSION = v3.1.0-2
 QEMU_STATIC = https://github.com/multiarch/qemu-user-static/releases/download/$(QEMU_VERSION)/qemu-arm-static.tar.gz