---
# The GitLab port of .github/workflows/. Both are maintained; see
# docs/ci-gitlab.md for what differs and why.
#
# Two ways in, and only two:
#   - a human presses play on a per-stack button (all manual, at the bottom)
#   - another project's pipeline asks for a stack by name (deploy:triggered)
#
# Nothing deploys on a plain push.

# Branch pipelines only. Any job carrying `rules: - when: manual` with no `if:`
# matches every pipeline source -- and that alone is enough to make GitLab build
# a *merge request* pipeline whenever an MR is open. A merge request pipeline
# includes only jobs whose rules match merge_request_event, so it drops every job
# that has no `rules:` at all. The result looks exactly like the deploy buttons
# having vanished, while the branch pipeline beside it has them all.
#
# Nothing here needs a merge request pipeline: the lint gate and the manual
# buttons both belong to a branch. Skipping them also stops one commit building
# two pipelines. With no MR pipeline the MR page shows the branch pipeline for
# its head commit, so the widget is not empty.
workflow:
  rules:
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      when: never
    - when: always

stages:
  - test
  - deploy

variables:
  # A runner's build directory is world-writable, and Ansible refuses to read an
  # ansible.cfg out of a world-writable directory -- it says so and carries on
  # with no roles_path and no inventory, which surfaces much later as "the role
  # 'compose_stack' was not found". Naming the file explicitly opts out of that
  # discovery rule. Paths inside it then resolve relative to the file, so this
  # works from any working directory.
  ANSIBLE_CONFIG: $CI_PROJECT_DIR/ansible/ansible.cfg

lint:
  stage: test
  image: python:3.12-slim
  # No `changes:` filter on purpose. Watching ansible/ and the lint configs means
  # a commit touching only this file skips the job entirely -- including the
  # commits fixing the lint job itself, so it silently proves nothing. The job
  # takes under a minute.
  script:
    - apt-get update -qq && apt-get install -qq -y --no-install-recommends git
    # scripts/check.sh is the single source of the version pins, and runs the
    # same three checks a contributor runs locally with `make check`.
    - ./scripts/check.sh --print-specs | xargs -d '\n' pip install --quiet
    - RUNNER=installed ./scripts/check.sh

# Shared setup: toolchain and the deploy key. Carries no rules of its own, so it
# can never schedule itself.
.ansible:
  stage: deploy
  # Every job that touches a host inherits this through `extends`. Remove it, or
  # change it to your own runner's tag, if your hosts are reachable from shared
  # runners. Do not add a tag before a runner carries it -- a tag no runner has
  # leaves jobs pending forever rather than failing.
  tags:
    - deploy-runner
  image: python:3.12-slim
  variables:
    SSH_KEY_BACKEND: ci
    ANSIBLE_FORCE_COLOR: '1'
  before_script:
    - apt-get update -qq && apt-get install -qq -y --no-install-recommends openssh-client curl rsync
    - ./scripts/check.sh --print-specs | head -1 | xargs -d '\n' pip install --quiet
    - ansible-galaxy install -r ansible/requirements.yml
    # Two lines, not `export SSH_KEY_PATH="$(...)"`. export is a special builtin,
    # so the compound command reports *its* status and swallows the script's --
    # under `set -e` a loader failure (an unprotected ref, so no key variable)
    # goes unnoticed and the job dies much later with a per-host "Permission
    # denied (publickey)" instead of the loader's own message.
    - SSH_KEY_PATH="$(./scripts/load-ssh-key.sh)"
    - export SSH_KEY_PATH

# Can the runner reach the hosts with the configured key? Changes nothing, so it
# is the right first thing to run after setting up the CI/CD variables.
ansible:ping:
  extends: .ansible
  rules:
    - when: manual
  script:
    - cd ansible && ansible all -m ansible.builtin.ping

# Runs one stack's playbook. STACK reaches a shell command and, for triggered
# pipelines, arrives from outside this project, so it is validated first.
.ansible-stack:
  extends: .ansible
  script:
    # A per-stack button pins STACK_FIXED; the generic and triggered jobs take
    # STACK as a pipeline variable. These cannot share one name: a pipeline
    # variable outranks a job's YAML `variables:` in GitLab, so with both called
    # STACK, pressing deploy:webapp inside a pipeline triggered with
    # STACK=static-site would deploy static-site -- and with PULL=always could
    # run webapp's backup and migration against the wrong stack.
    - STACK="${STACK_FIXED:-${STACK:-}}"
    - case "$STACK" in ''|*[!a-z0-9_-]*) echo "refusing STACK='$STACK'"; exit 1;; esac
    # PULL reaches the same command line, unquoted, from the same untrusted place
    # as STACK, so it gets the same treatment: an unchecked value can smuggle in
    # extra `-e` overrides (stack_dest, ansible_host) and redirect a deploy.
    - case "$PULL" in ''|always|missing|never|policy) ;; *) echo "refusing PULL='$PULL'"; exit 1;; esac
    - test -f "ansible/playbooks/${STACK}.yml" || { echo "no playbook for '$STACK'"; exit 1; }
    - cd ansible && ansible-playbook "playbooks/${STACK}.yml" ${ANSIBLE_EXTRA_ARGS} ${PULL:+-e pull=$PULL}

# Run a pipeline with STACK set (Build > Pipelines > Run pipeline, add a
# variable) and these two appear.
check:stack:
  extends: .ansible-stack
  variables:
    ANSIBLE_EXTRA_ARGS: --check --diff
  rules:
    - if: '$STACK'
      when: manual

deploy:stack:
  extends: .ansible-stack
  rules:
    - if: '$STACK'
      when: manual

# Deploy on request from another project's pipeline. This job exists only in
# pipelines that were triggered, so it can never fire on a push here.
# See docs/triggering-deploys.md.
deploy:triggered:
  extends: .ansible-stack
  rules:
    # trigger token or API call
    - if: '$CI_PIPELINE_SOURCE == "trigger" && $STACK'
    # `trigger:` keyword in an upstream project (multi-project pipeline)
    - if: '$CI_PIPELINE_SOURCE == "pipeline" && $STACK'

.ansible-manual:
  extends: .ansible-stack
  when: manual
  # A bare `when: manual` defaults allow_failure to true, unlike `when: manual`
  # inside `rules:`. Without this a failed deploy leaves the pipeline green and
  # an upstream using `strategy: depend` never learns the deploy broke.
  allow_failure: false

# One visible button per stack. Written out rather than generated with
# parallel:matrix: a matrix collapses into a single expandable node in the
# pipeline graph, which hides every play button one click deeper. Named jobs each
# get their own button.
#
#   check:<stack>    --check --diff, reports what would change, touches nothing
#   deploy:<stack>   does it
#
# To update rather than deploy, run the pipeline with PULL=always and press the
# same deploy button. That also enables the work gated behind an update run --
# webapp's backup and migration.
#
# Order mirrors ansible/playbooks/site.yml. Add a pair when a playbook lands.
.check:
  extends: .ansible-manual
  variables:
    ANSIBLE_EXTRA_ARGS: --check --diff

.deploy:
  extends: .ansible-manual

check:reverse-proxy:
  extends: .check
  variables:
    STACK_FIXED: reverse-proxy

deploy:reverse-proxy:
  extends: .deploy
  variables:
    STACK_FIXED: reverse-proxy

check:banner:
  extends: .check
  variables:
    STACK_FIXED: banner

deploy:banner:
  extends: .deploy
  variables:
    STACK_FIXED: banner

check:metrics:
  extends: .check
  variables:
    STACK_FIXED: metrics

deploy:metrics:
  extends: .deploy
  variables:
    STACK_FIXED: metrics

check:static-site:
  extends: .check
  variables:
    STACK_FIXED: static-site

deploy:static-site:
  extends: .deploy
  variables:
    STACK_FIXED: static-site

check:webapp:
  extends: .check
  variables:
    STACK_FIXED: webapp

deploy:webapp:
  extends: .deploy
  variables:
    STACK_FIXED: webapp

check:webapp-staging:
  extends: .check
  variables:
    STACK_FIXED: webapp-staging

deploy:webapp-staging:
  extends: .deploy
  variables:
    STACK_FIXED: webapp-staging