SixFlagsSuperCalendar/docs/OPERATIONS.md

Operations

See also: Architecture | API Reference | Development

Deployment Overview

The application runs as two Docker containers:

Container	Port	Role
web	3000	Next.js frontend (stateless, no database)
backend	3001	Hono API server (owns SQLite database, runs cron scheduler)

Infrastructure requirements:

• Docker host with Docker Compose
• Container registry (Gitea, Docker Hub, or any OCI-compatible registry)
• Outbound HTTPS access to d18car1k0ff81h.cloudfront.net (Six Flags API) and queue-times.com (live ride data)
• A reverse proxy (Traefik, nginx, Caddy, etc.) is expected to sit in front for TLS termination and domain routing, but is not included in this repository

See Architecture for detailed system design.

---

Docker Images

Multi-Stage Build

The project uses a single Dockerfile with four stages producing two final images:

  builder           backend-deps
  (Next.js build)   (native modules)
      |                   |
      v                   v
    web               backend
  (final)             (final)

Stage	Base	Purpose
builder	node:22-bookworm-slim	npm ci + npm run build -- produces Next.js standalone output
backend-deps	node:22-bookworm-slim	Installs python3, make, g++ for better-sqlite3 native compilation, then npm ci
web (final)	node:22-bookworm-slim	Copies standalone output from builder. Non-root user. ~150MB.
backend (final)	node:22-bookworm-slim	Copies node_modules from backend-deps + source code. Volume for SQLite. Non-root user. ~200MB.

Image Tags

{registry}/{owner}/sixflagssupercalendar:web
{registry}/{owner}/sixflagssupercalendar:backend

Building Locally

# Build web image
docker build --target web -t sixflagssupercalendar:web .

# Build backend image
docker build --target backend -t sixflagssupercalendar:backend .

---

Docker Compose

The production docker-compose.yml:

services:
  web:
    image: gitea.thewrightserver.net/josh/sixflagssupercalendar:web
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - BACKEND_URL=http://backend:3001    # Docker internal networking
    restart: unless-stopped

  backend:
    image: gitea.thewrightserver.net/josh/sixflagssupercalendar:backend
    ports:
      - "3001:3001"
    volumes:
      - park_data:/app/data                # SQLite database persistence
    environment:
      - NODE_ENV=production
      - TZ=America/New_York                # Timezone for cron schedules
      - PARK_HOURS_STALENESS_HOURS=72      # Hours before re-fetching park data
    restart: unless-stopped

volumes:
  park_data:                               # Named volume for database files

Networking: The web container reaches the backend via Docker's internal DNS at http://backend:3001. The backend port is also exposed to the host for manual API access during troubleshooting.

---

Environment Variables

Web Container

Variable	Default	Description
BACKEND_URL	http://localhost:3001	Backend API base URL. Set to http://backend:3001 in Docker Compose for internal networking.
NODE_ENV	--	Set to production in Docker.
NEXT_TELEMETRY_DISABLED	1	Disables Next.js telemetry (set in Dockerfile).
PORT	3000	Server listen port (set in Dockerfile).
HOSTNAME	0.0.0.0	Bind address (set in Dockerfile to allow external access).

Backend Container

Variable	Default	Description
TZ	UTC	Process timezone. Controls when cron jobs fire. Set to America/New_York in production so schedules align with US Eastern parks.
PARK_HOURS_STALENESS_HOURS	72	Hours before park schedule data is considered stale and re-fetched. Lower values increase API load; higher values increase data lag.
NODE_ENV	--	Set to production in Docker.
PORT	3001	Server listen port.

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CI/CD Pipeline

Gitea Actions Workflow

File: .gitea/workflows/deploy.yml

Trigger: Push to main branch.

Steps:

1. Checkout code (actions/checkout@v4)
2. Log in to Gitea container registry
3. Build and push web image (docker/build-push-action@v6, target: web)
4. Build and push backend image (docker/build-push-action@v6, target: backend)

Required Configuration

Type	Name	Description
Variable	REGISTRY	Container registry URL (e.g. gitea.thewrightserver.net)
Secret	REGISTRY_TOKEN	Authentication token for the registry

These are configured in the Gitea repository settings under Settings > Actions > Secrets and Settings > Actions > Variables.

Setting Up CI/CD from Scratch

1. Create a Gitea repository
2. Add REGISTRY as a repository variable (Settings > Actions > Variables)
3. Add REGISTRY_TOKEN as a repository secret (Settings > Actions > Secrets)
4. Push to main -- the workflow triggers automatically
5. Pull images on your Docker host: docker compose pull && docker compose up -d

---

Initial Deployment Checklist

1. Create a docker-compose.yml on your Docker host (see the Docker Compose section above, or use the one from the repository).

2. Pull and start the containers:

   docker compose pull
   docker compose up -d
   

3. Verify the backend started:

   docker compose logs backend
   # Look for: [backend] database initialized
   #           [scheduler] cron jobs registered
   #           [backend] listening on http://localhost:3001
   

4. Check database status (will be empty on first run):

   curl http://localhost:3001/api/status
   # { "status": "ok", "database": { "totalDays": 0, ... } }
   

5. Trigger the initial data scrape:

   curl -X POST http://localhost:3001/api/scrape/trigger?scope=full
   

   This scrapes all 12 months for all 24 parks with a 1-second delay between parks. Expected duration: 5-10 minutes.

6. Verify data was scraped:

   curl http://localhost:3001/api/status
   # totalDays should be ~8000-9000
   

7. Open the web UI: Navigate to http://your-host:3000.

The cron scheduler starts automatically and will keep data fresh going forward.

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Updating

docker compose pull && docker compose up -d

• The SQLite database lives in a named Docker volume (park_data), so it persists across container recreations.
• Schema migrations are applied automatically on backend startup. New columns are added via ALTER TABLE ... ADD COLUMN wrapped in try/catch -- if the column already exists, the error is silently caught.
• No manual migration steps are needed.

---

Backup and Restore

What to Back Up

The SQLite database at /app/data/parks.db inside the park_data Docker volume. WAL journal files (parks.db-wal and parks.db-shm) must be included for a consistent backup.

Backup Methods

Method 1: Copy from the container

docker compose cp backend:/app/data/parks.db ./backup/parks.db
docker compose cp backend:/app/data/parks.db-wal ./backup/parks.db-wal 2>/dev/null
docker compose cp backend:/app/data/parks.db-shm ./backup/parks.db-shm 2>/dev/null

Method 2: Mount the volume to the host Add a bind mount in docker-compose.yml:

volumes:
  - ./data:/app/data

Restore

1. Stop the backend: docker compose stop backend
2. Replace the database files in the volume
3. Restart: docker compose start backend

Note on Reproducibility

All data is sourced from external APIs and is fully reproducible. If the database is lost, simply restart the backend (which auto-creates an empty database) and trigger a full scrape:

curl -X POST http://localhost:3001/api/scrape/trigger?scope=full

Backups are recommended for continuity (avoiding the 5-10 minute re-scrape window) but are not critical.

---

Scheduler Operations

Tiered Cron Schedule

The backend runs four scraping tiers via node-cron:

Tier	Cron Expression	Schedule	Scope	Delay
1	0 * * 3-12 *	Hourly, March through December	Today's hours for all parks	500ms
2	0 */6 * * *	Every 6 hours	Current month for all parks	1000ms
3	0 3,15 * * *	3 AM and 3 PM	Current + next month	1000ms
4	0 3 * * *	Daily at 3 AM	Full year (all 12 months)	1000ms

Staleness: Tiers 2-4 skip any park-month that was scraped within PARK_HOURS_STALENESS_HOURS (default 72h). Tier 1 always fetches (uses diff-before-write instead).

Off-season: Tier 1 only runs from March through December. The month constraint 3-12 in the cron expression skips January and February when most parks are closed.

Timezone Sensitivity

Cron expressions execute in the process timezone, controlled by the TZ environment variable. In production this is set to America/New_York so that "3 AM" aligns with US Eastern time.

The per-park timezone (e.g. America/Los_Angeles for Magic Mountain) is used separately for operating window detection -- it does not affect cron schedule timing.

The 3 AM Switchover

getTodayLocal() in lib/env.ts implements a 3 AM local-time switchover: before 3 AM, the system considers it "yesterday." This prevents the calendar from flipping to the next day at midnight while park visitors are still out. The switchover uses the server's local time (influenced by TZ), not individual park timezones.

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Manual Scraping

Trigger a scrape at any time via the backend API:

curl -X POST http://localhost:3001/api/scrape/trigger?scope=<scope>

Scope Options

Scope	Behavior	Duration
today	Fetches today's hours for all 24 parks. Diffs against database before writing. 500ms delay.	~15s
month	Current month for all parks. Respects staleness window. 1000ms delay.	~30s
upcoming	Current + next month. Respects staleness.	~1min
full	All 12 months. Respects staleness.	~5-10min
force	All 12 months. Ignores staleness -- forces re-fetch of everything.	~5-10min

Response

{
    "scope": "today",
    "fetched": 24,
    "skipped": 0,
    "errors": 0,
    "updated": 3,
    "startedAt": "2026-04-23T14:00:00.000Z",
    "finishedAt": "2026-04-23T14:00:12.000Z"
}

Typical Use Cases

• After initial deployment: scope=full to populate the database
• After an extended outage: scope=force to refresh all data regardless of staleness
• Investigating a specific park: scope=today to get fresh data quickly
• Before peak season: scope=full to ensure complete coverage

---

Health Monitoring

Health Endpoint

curl http://localhost:3001/api/status

Response

{
    "status": "ok",
    "uptime": 86400,
    "parks": 24,
    "database": {
        "totalDays": 8760,
        "lastScrape": "2026-04-23T14:00:12.000Z"
    },
    "lastScrapeResult": {
        "scope": "today",
        "fetched": 24,
        "skipped": 0,
        "errors": 0,
        "updated": 3,
        "startedAt": "2026-04-23T14:00:00.000Z",
        "finishedAt": "2026-04-23T14:00:12.000Z"
    }
}

Key Metrics

Metric	Expected Value	Concern If
status	"ok"	Not "ok" (always "ok" currently, but confirms the endpoint is reachable)
uptime	Increasing	Drops to 0 (container restarted)
database.totalDays	8,000-9,000 (full year)	Much lower (scraping not running) or 0 (empty database)
database.lastScrape	Within the last hour (during operating season)	More than a few hours old (scheduler may be broken)
lastScrapeResult.errors	0	Consistently high (API may be blocking requests)

Suggested Alerting

• Alert if database.lastScrape is more than 12 hours old during operating season (March-December)
• Alert if lastScrapeResult.errors exceeds 5 on consecutive scrapes
• Alert if the health endpoint is unreachable

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Troubleshooting

No data showing in the calendar

1. Check if the backend is running:

   docker compose logs backend --tail 50
   

   Look for [backend] listening on http://localhost:3001.

2. Check if the database has data:

   curl http://localhost:3001/api/status | jq .database.totalDays
   

   If 0, trigger a manual scrape: curl -X POST http://localhost:3001/api/scrape/trigger?scope=full

3. Check the BACKEND_URL in the web container:

   docker compose exec web env | grep BACKEND_URL
   

   Should be http://backend:3001 (not localhost, which won't resolve inside Docker).

Ride counts not appearing on the home page

• Ride counts only appear for parks that are currently within their operating window, as determined by isWithinOperatingWindow(). Outside of park hours, no rides are shown.
• Queue-Times data is cached for 5 minutes. Recent park openings may take up to 5 minutes to appear.
• Weather delay (blue badge) means the park is within its hours but all rides report closed -- this is expected during weather-related closures.
• Verify the park has a Queue-Times mapping in lib/queue-times-map.ts.

Stale data / not updating

1. Check scheduler logs:

   docker compose logs backend | grep scheduler
   

   You should see periodic [scheduler] tier-X: scraping... messages.

2. Verify timezone:

   docker compose exec backend date
   

   Should match the TZ environment variable (America/New_York).

3. Check staleness threshold: Data within PARK_HOURS_STALENESS_HOURS (default 72h) is skipped by tiers 2-4. If you recently changed park data manually, it may not be re-fetched until the staleness window expires.

4. Force a refresh:

   curl -X POST http://localhost:3001/api/scrape/trigger?scope=force
   

Rate limited by Six Flags API

• Look for [rate-limited] messages in the backend logs:

  docker compose logs backend | grep rate-limited
  

• The client uses exponential backoff: 30s, 60s, 120s, then throws a RateLimitError and moves to the next park.
• If rate limiting is persistent, increase PARK_HOURS_STALENESS_HOURS to reduce scrape frequency (e.g. 96 or 120).
• The inter-park delay is hardcoded at 1000ms (500ms for the today tier) in backend/src/services/scraper.ts.

Wrong timezone / incorrect dates

• getTodayLocal() uses the server's local time (set by TZ env var) with a 3 AM cutover. Before 3 AM, the system considers it "yesterday."
• Each park has its own IANA timezone (stored in lib/parks.ts) used for operating window checks. The TZ env var only affects cron schedule timing and the "today" determination.
• If dates seem off, check both TZ and the server's system clock:

  docker compose exec backend date
  docker compose exec backend node -e "console.log(new Date().toISOString())"
  

Database corruption

If the database becomes corrupted (unlikely with SQLite WAL mode, but possible after a hard crash):

1. Stop the backend: docker compose stop backend
2. Delete the database files from the volume:

   docker compose run --rm backend rm -f /app/data/parks.db /app/data/parks.db-wal /app/data/parks.db-shm
   

3. Restart: docker compose start backend (auto-creates empty database)
4. Re-scrape: curl -X POST http://localhost:3001/api/scrape/trigger?scope=full

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Log Reference

Prefix	Source	Meaning
[backend]	index.ts	Startup messages: DB initialized, server listening
[scheduler]	scheduler.ts	Cron job triggers with tier number
[today]	scraper.ts	Per-park results for the today tier (updated/skipped/error)
[month]	scraper.ts	Per-park-month results (open days count, rate limited, errors)
[rate-limited]	sixflags.ts	HTTP 429/503 with backoff timing and retry attempt count

Example log output:

[backend] database initialized
[scheduler] cron jobs registered
  tier-1: today        — hourly (Mar-Dec)
  tier-2: current month — every 6h
  tier-3: upcoming     — 3 AM + 3 PM
  tier-4: full year    — 3 AM daily
[backend] listening on http://localhost:3001
[scheduler] tier-1: scraping today @ 2026-04-23T14:00:00.000Z
[today] Great Adventure: updated (open 10am - 6pm)
[today] Cedar Point: updated (open 10am - 8pm)
[today] done: 24 fetched, 3 updated, 0 skipped, 0 errors

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Performance Tuning

Aspect	Current Setting	Notes
SQLite WAL mode	Enabled	Allows concurrent reads during writes. No configuration needed.
In-memory cache	TtlCache (5 min TTL)	Bounded by park count -- at most ~72 entries (24 parks x 3 caches). Memory impact is negligible.
Staleness window	72 hours	Controls how often park data is re-fetched from the API. Lower values = fresher data but more API calls and higher rate-limit risk.
Inter-park delay	1000ms / 500ms	Hardcoded in scraper.ts. Provides respectful pacing against the Six Flags API.
ISR revalidation	60-300s per route	Controlled in Next.js fetch calls. Lower values = fresher pages but more backend requests.
Next.js standalone	Enabled	Produces a minimal server bundle without unused dependencies.