ENH: use cached docker image building

.gitlab-ci.yml

@@ -22,10 +22,6 @@ variables:
    CI_REGISTRY_IMAGE: $CI_REGISTRY/caosdb-webui-testenv
    # When using dind, it's wise to use the overlayfs driver for
    # improved performance.
-   DOCKER_DRIVER: overlay2
-
-services:
-   - docker:19.03-dind
 
 image: $CI_REGISTRY_IMAGE:latest
 
@@ -63,7 +59,7 @@ trigger_build:
   script:
     - echo $TOKEN     
     - /usr/bin/curl -X POST
-       -F token=$TOKEN
+       -F token=$DEPLOY_TRIGGER_TOKEN
        -F "variables[WEBUI]=$CI_COMMIT_REF_NAME"
        -F "variables[TriggerdBy]=WEBUI"
        -F "variables[TriggerdByHash]=$CI_COMMIT_SHORT_SHA"
@@ -71,12 +67,12 @@ trigger_build:
 
 # Build a docker image in which tests for this repository can run
 build-testenv:
-  tags: [ docker ]
+  tags: [ cached-dind ]
   image: docker:19.03
   stage: setup
   script: 
     - cd test/docker
-    - docker login -u testuser -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker login -u indiscale -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
       # use here general latest or specific branch latest...
     - docker pull $CI_REGISTRY_IMAGE:latest || true
     - docker build