Cd/setup

.github/workflows/ci.yml

@@ -1,4 +1,4 @@
-name: CI
+name: CI/CD
 
 on:
   push:
@@ -96,3 +96,54 @@ jobs:
       # Reported for information. A drop in coverage does not fail the build.
       - name: Coverage report
         run: coverage report
+
+  deploy:
+    name: Deploy
+    runs-on: ubuntu-latest
+    needs: [lint, test]
+    timeout-minutes: 10
+
+    # Pull requests run the checks above, but never deploy.
+    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
+
+    # Two merges in quick succession must never deploy at the same time.
+    # A later run waits for the running one instead of cancelling it.
+    concurrency:
+      group: deploy-production
+      cancel-in-progress: false
+
+    steps:
+      - uses: actions/checkout@v7
+
+      # ssh refuses a private key file that others can read, hence chmod 600.
+      - name: Set up SSH
+        run: |
+          mkdir -p ~/.ssh
+          chmod 700 ~/.ssh
+          echo "${{ secrets.SSH_PRIVATE_KEY }}" > ~/.ssh/deploy_key
+          chmod 600 ~/.ssh/deploy_key
+          echo "${{ secrets.SSH_KNOWN_HOSTS }}" > ~/.ssh/known_hosts
+          chmod 644 ~/.ssh/known_hosts
+
+      # The script is never copied to the server: bash reads it from stdin.
+      # github.sha is exactly the commit the checks above have tested.
+      - name: Deploy to server (dry run)
+        run: |
+          ssh -i ~/.ssh/deploy_key \
+            "${{ secrets.SSH_USER }}@${{ secrets.SSH_HOST }}" \
+            "bash -s -- ${{ github.sha }}" < deploy/deploy.sh
+
+      # A 200 alone proves little. The content type shows that the right
+      # kind of file came back: JSON from Django, CSS from collectstatic.
+      - name: Verify site
+        run: |
+          check() {
+            result=$(curl -sS -o /dev/null -w '%{http_code} %{content_type}' "$1")
+            echo "$1 -> $result"
+            case "$result" in
+              "200 $2"*) ;;
+              *) echo "Expected 200 $2" >&2; exit 1 ;;
+            esac
+          }
+          check https://coderr.benjaminblarr.de/api/base-info/ application/json
+          check https://coderr.benjaminblarr.de/static/admin/css/base.css text/css

deploy/deploy.sh

@@ -0,0 +1,83 @@
+#!/usr/bin/env bash
+# Deploys one commit of the Coderr backend. Runs on the server and is fed
+# through ssh by the deploy job in .github/workflows/ci.yml:
+#   ssh <host> "bash -s -- <commit-sha>" < deploy/deploy.sh
+#
+# First version: dry run only. It reports what a deployment would change
+# and takes a database backup, but touches neither code nor database.
+set -euo pipefail
+
+APP_DIR=/var/www/coderr/backend
+BACKUP_DIR="$HOME/backups/coderr"
+KEEP_BACKUPS=10
+
+sha="${1:-}"
+if [[ ! "$sha" =~ ^[0-9a-f]{40}$ ]]; then
+    echo "Usage: deploy.sh <full commit sha>" >&2
+    exit 1
+fi
+
+# Never add "set -x" to this script: it would print the database password
+# into the public log of the workflow run.
+env_value() {
+    local value
+    value="$(grep -m1 "^$1=" .env | cut -d= -f2- | tr -d "\r\"'")" || true
+    if [ -z "$value" ]; then
+        echo "$1 is missing in .env" >&2
+        exit 1
+    fi
+    printf '%s' "$value"
+}
+
+backup_database() {
+    local db_name db_user db_password db_host db_port file
+    db_name="$(env_value DB_NAME)"
+    db_user="$(env_value DB_USER)"
+    db_password="$(env_value DB_PASSWORD)"
+    db_host="$(env_value DB_HOST)"
+    db_port="$(env_value DB_PORT)"
+    file="$BACKUP_DIR/$(date +%Y-%m-%d_%H%M%S)_${sha:0:7}.sql.gz"
+
+    mkdir -p "$BACKUP_DIR"
+    chmod 700 "$HOME/backups"
+    rm -f "$BACKUP_DIR"/*.partial
+    PGPASSWORD="$db_password" pg_dump -h "$db_host" -p "$db_port" \
+        -U "$db_user" "$db_name" | gzip > "$file.partial"
+    mv "$file.partial" "$file"
+    echo "Backup: $file ($(du -h "$file" | cut -f1))"
+
+    ls -1t "$BACKUP_DIR"/*.sql.gz | tail -n +$((KEEP_BACKUPS + 1)) \
+        | xargs -r rm --
+}
+
+cd "$APP_DIR"
+
+# Tracked files edited by hand on the server would get mixed with the new
+# commit. Stop and name them instead.
+if [ -n "$(git status --porcelain --untracked-files=no)" ]; then
+    echo "Tracked files were changed on the server:" >&2
+    git status --short --untracked-files=no >&2
+    exit 1
+fi
+
+git fetch --quiet origin
+git cat-file -e "$sha^{commit}"
+echo "Server: $(git log --oneline -1 HEAD)"
+echo "Target: $(git log --oneline -1 "$sha")"
+
+if ! git merge-base --is-ancestor HEAD "$sha"; then
+    echo "Target does not build on the server's commit." >&2
+    exit 1
+fi
+
+echo "--- Changed files ---"
+git diff --stat HEAD "$sha"
+echo "--- New migration files ---"
+git diff --name-only --diff-filter=A HEAD "$sha" -- '*/migrations/*.py'
+echo "--- Changes to requirements.txt ---"
+git diff HEAD "$sha" -- requirements.txt
+echo "--- Unapplied migrations of the running code ---"
+.venv/bin/python manage.py migrate --plan
+
+backup_database
+echo "Dry run finished, nothing was deployed."