feat: add 37signals Once platform compatibility (#37)

Author: markhallen

.github/workflows/release.yml

@@ -10,6 +10,7 @@ env:
 
 permissions:
   contents: write
+  packages: write
 
 jobs:
   release:
@@ -85,3 +86,40 @@ jobs:
         files: slack-github-threads-v${{ steps.version.outputs.VERSION }}.tar.gz
         draft: false
         prerelease: false
+
+  docker:
+    runs-on: ubuntu-latest
+    needs: release
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Extract version from tag
+      id: version
+      run: |
+        VERSION=${GITHUB_REF#refs/tags/v}
+        echo "VERSION=$VERSION" >> $GITHUB_OUTPUT
+
+    - name: Log in to GitHub Container Registry
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Build and push Docker image
+      uses: docker/build-push-action@v6
+      with:
+        context: .
+        push: true
+        tags: |
+          ghcr.io/${{ github.repository }}:${{ steps.version.outputs.VERSION }}
+          ghcr.io/${{ github.repository }}:latest
+        labels: |
+          org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}
+          org.opencontainers.image.version=${{ steps.version.outputs.VERSION }}
+          org.opencontainers.image.revision=${{ github.sha }}

Dockerfile

@@ -10,4 +10,9 @@ ENV RACK_ENV=production
 ENV PORT=80
 EXPOSE 80
 
+# Once platform: persistent storage and backup/restore hooks
+RUN mkdir -p /storage/log
+COPY once/hooks/ /hooks/
+RUN chmod +x /hooks/*
+
 CMD ["bundle", "exec", "puma", "-C", "config/puma.rb"]

README.md

@@ -220,6 +220,10 @@ This project is configured for deployment using [Kamal](https://kamal-deploy.org
 kamal deploy
 ```
 
+## Once Platform
+
+This app is compatible with [37signals' Once](https://once.com/) for self-hosted, single-tenant deployment. Docker images are published to GHCR on each release and can be installed directly from the Once installer. See [docs/ONCE.md](docs/ONCE.md) for setup details.
+
 ## Docker
 
 You can also run the application using Docker:

app.rb

@@ -20,7 +20,11 @@
   set :debug_mode, ENV.fetch('DEBUG', nil) == 'true' || development?
 
   # Setup logging
-  log_dir = File.join(settings.root, 'log')
+  log_dir = if Dir.exist?('/storage')
+              '/storage/log'
+            else
+              File.join(settings.root, 'log')
+            end
   FileUtils.mkdir_p(log_dir)
 
   log_file = File.join(log_dir, "#{settings.environment}.log")

config/puma.rb

@@ -5,7 +5,7 @@
 environment ENV.fetch('RACK_ENV', 'production')
 
 # Number of worker processes
-workers ENV.fetch('WEB_CONCURRENCY', 2)
+workers ENV.fetch('WEB_CONCURRENCY') { ENV.fetch('NUM_CPUS', 2) }
 
 # Number of threads per worker
 threads_count = ENV.fetch('RAILS_MAX_THREADS', 5)

docs/ONCE.md

@@ -0,0 +1,45 @@
+# Once Platform Deployment
+
+This application is compatible with [37signals' Once](https://once.com/) platform.
+
+## Installation
+
+When the Once installer prompts for a Docker image path, enter:
+
+```
+ghcr.io/markhallen/slack-github-threads:latest
+```
+
+Or pin to a specific version (e.g., `ghcr.io/markhallen/slack-github-threads:1.0.0`).
+
+## Compatibility
+
+The app meets all Once requirements:
+
+| Requirement | Status |
+|-------------|--------|
+| Docker container | Yes |
+| HTTP on port 80 | Yes |
+| Health check at `/up` | Yes (returns 200 OK) |
+| Persistent data in `/storage` | Yes (logs only) |
+
+## Environment Variables
+
+**Required** (set in Once admin UI):
+
+- `SLACK_BOT_TOKEN` — Slack bot token (starts with `xoxb-`)
+- `GITHUB_TOKEN` — GitHub personal access token (starts with `ghp_`)
+
+**Automatically provided by Once:**
+
+- `NUM_CPUS` — Used to set Puma worker count (falls back to `WEB_CONCURRENCY`, then default of 2)
+- `SECRET_KEY_BASE` — Injected but not used by this app
+- `DISABLE_SSL` — Injected but not used (SSL is handled by the reverse proxy)
+
+## Storage
+
+The app is stateless — no database or file uploads. The `/storage` volume is used only for log files at `/storage/log/`. When running outside Once, logs fall back to `log/` in the app directory.
+
+## Backup and Restore
+
+The Once hook scripts at `/hooks/pre-backup` and `/hooks/post-restore` are no-ops because the app has no stateful data to back up. Source files are in `once/hooks/` in the repository.

once/hooks/post-restore

@@ -0,0 +1,3 @@
+#!/bin/sh
+# No-op: app has no database or stateful data to restore.
+exit 0

once/hooks/pre-backup

@@ -0,0 +1,3 @@
+#!/bin/sh
+# No-op: app has no database or stateful data to flush before backup.
+exit 0