Deploying to Fly.io

Deploy your EreoJS application to Fly.io for globally distributed hosting.

Prerequisites

• A Fly.io account
• The Fly CLI installed: curl -L https://fly.io/install.sh | sh
• Authenticate: fly auth login

Dockerfile

Create a Dockerfile in your project root:

FROM oven/bun:1-slim AS deps
WORKDIR /app
COPY package.json bun.lockb ./
RUN bun install --frozen-lockfile --production

FROM oven/bun:1 AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN bun run build

FROM oven/bun:1-slim AS runner
WORKDIR /app

ENV NODE_ENV=production

RUN addgroup --system --gid 1001 app && \
    adduser --system --uid 1001 --ingroup app app

COPY --from=builder --chown=app:app /app/dist ./dist
COPY --from=builder --chown=app:app /app/node_modules ./node_modules
COPY --from=builder --chown=app:app /app/package.json ./

USER app

EXPOSE 3000

CMD ["bun", "ereo", "start"]

Fly Configuration

Create a fly.toml configuration file:

# fly.toml
app = "my-ereo-app"
primary_region = "iad"

[build]

[http_service]
  internal_port = 3000
  force_https = true
  auto_stop_machines = "stop"
  auto_start_machines = true
  min_machines_running = 1

[checks]
  [checks.health]
    type = "http"
    port = 3000
    path = "/api/health"
    interval = "30s"
    timeout = "5s"

Launch and Deploy

Initialize the Fly app:

fly launch

This detects the Dockerfile, creates the app on Fly.io, and prompts for configuration. Review the settings and confirm.

Deploy:

fly deploy

Fly builds the Docker image remotely and deploys it. Subsequent deploys only rebuild changed layers.

Secrets Management

Set environment variables as Fly secrets (encrypted, not stored in fly.toml):

fly secrets set DATABASE_URL="postgres://user:pass@host:5432/db"
fly secrets set SESSION_SECRET="your-secret-here"

List current secrets:

fly secrets list

Secrets are injected as environment variables at runtime and are available via process.env.

Scaling Across Regions

Deploy to multiple regions for lower latency:

# Add a region
fly scale count 2 --region iad,cdg

# List current machines
fly status

Common regions:

• iad --- Ashburn, Virginia (US East)
• lax --- Los Angeles (US West)
• cdg --- Paris (Europe)
• nrt --- Tokyo (Asia)

Database with Fly Postgres

Create a Fly Postgres database:

fly postgres create --name my-ereo-db
fly postgres attach my-ereo-db

This automatically sets the DATABASE_URL secret on your app.

Volumes for Persistent Storage

If your app needs persistent file storage (uploads, SQLite):

fly volumes create data --size 1 --region iad

Mount it in fly.toml:

[mounts]
  source = "data"
  destination = "/app/data"

Monitoring

View application logs:

fly logs

Check deployment status:

fly status

Open the deployed app in your browser:

fly open

Continuous Deployment

See the CI/CD guide for setting up automatic deploys from GitHub Actions when pushing to main.