use gnu parallel to trigger parallel checkupdates pipelines

Batch checkupdate invocations into calls with 100 apps. This should
allow more than enough headroom for gitlab CI runner limits.
Currently it'll spawn 34 child pipelines, these each complete in about
15-20 min.

.gitlab-ci.yml

@@ -2,8 +2,12 @@ image: registry.gitlab.com/fdroid/ci-images-server:latest
 
 lint:
   except:
-    - triggers
-    - schedules
+    refs:
+      - triggers
+      - schedules
+      - piplines
+    variables:
+      - $CHECKUPDATES
   before_script:
     - ./tools/trigger-issuebot
     - printf "Package\x3a androguard fdroidserver python3-asn1crypto python3-ruamel.yaml\nPin\x3a release a=stretch-backports\nPin-Priority\x3a 500\n" > /etc/apt/preferences.d/debian-stretch-backports.pref
@@ -56,11 +60,29 @@ lint:
     - ./tools/check-metadata-summary-whitespace.py || export EXITVALUE=1
     - exit $EXITVALUE
 
-checkupdates:
+checkupdates_trigger:
   only:
-    - schedules
+    refs:
+      - schedules
+    variables:
+      - $CHECKUPDATES == "true"
+  image: debian:buster-slim
+  before_script:
+    - apt-get update
+    - apt-get install -qy --no-install-recommends parallel curl ca-certificates
+  script:
+    - files=( metadata/*.yml )
+    - files=( ${files[@]#metadata/} )
+    - files=( ${files[@]%.yml} )
+    - parallel --verbose -N 100 'curl -X POST -F "token=$CI_JOB_TOKEN" -F "ref=master" -F "variables[CHECKUPDATES]=true" -F "variables[CHECKUPDATES_APPIDS]= {} " https://gitlab.com/api/v4/projects/${CI_PROJECT_ID}/trigger/pipeline' ":::" ${files[@]}
+
+checkupdates_runner:
+  only:
+    refs:
+      - pipelines
+    variables:
+      - $CHECKUPDATES == "true"
   before_script:
-    - if [ -z "${CHECKUPDATES}" ]; then exit 0; fi
     - printf "Package\x3a androguard fdroidserver python3-asn1crypto python3-ruamel.yaml\nPin\x3a release a=stretch-backports\nPin-Priority\x3a 500\n" > /etc/apt/preferences.d/debian-stretch-backports.pref
     - echo "deb http://deb.debian.org/debian/ stretch-backports main" > /etc/apt/sources.list.d/backports.list
     - apt-get update
@@ -77,8 +99,7 @@ checkupdates:
     - url_host=`git remote get-url origin | sed -e "s/https:\/\/gitlab-ci-token:.*@//g"`
     - git remote set-url origin "https://gitlab-ci-token:${CI_GIT_PUSH_TOKEN}@${url_host}"
   script:
-    - while true; sleep 300; do git pull --rebase origin master; git push origin HEAD:master; done&
-    - fdroid checkupdates --auto --commit --allow-dirty
+    - fdroid checkupdates --allow-dirty --auto --commit ${CHECKUPDATES_APPIDS}
     - git pull --rebase origin master
     - git push origin HEAD:master
 
@@ -140,6 +161,9 @@ pages:
   only:
     - triggers
     - web
+  except:
+    variables:
+      - $CHECKUPDATES
   artifacts:
     paths:
       - metadata/
@@ -188,14 +212,16 @@ check_git_repos:
   image: debian:buster-slim
   stage: test
   only:
-    - schedules
+    refs:
+      - schedules
+    variables:
+      - $CHECK_GIT_REPO == "true"
   artifacts:
     when: on_failure
     expire_in: 1 month
     paths:
       - public
   script:
-    - if [ -z "${CHECK_GIT_REPOS}" ]; then exit 0; fi
     - apt-get update
     - apt-get -qy install --no-install-recommends ca-certificates git python3-colorama python3-yaml
     - tools/check-git-repo-availability.py || export EXITVALUE=1