Modify the Dockerfile can make it adapt to any languages

Start with Single Service

Full Pipeline

Go app as example

Install

curl -L https://fly.io/install.sh | sh
fly auth signup # or fly auth login

follow the instruction to add the flyctl binary to your PATH

sudo nano ~/.bashrc

# add the following lines
export FLYCTL_INSTALL="/home/username/.fly"
export PATH="$FLYCTL_INSTALL/bin:$PATH"

Initialize your fly.io project

fly launch
# select app name, region, etc.
# fly.toml generated automatically

fly.toml settings A free tier example

# fly.toml app configuration file generated for ebbilogue-backend on 2025-02-03T03:25:42+09:00
#
# See https://fly.io/docs/reference/configuration/ for information about how to use this file.
#

app = 'app-name'
primary_region = 'nrt'

[build]

[http_service]
  internal_port = 6061
  force_https = true
  auto_stop_machines = 'stop'
  auto_start_machines = true
  min_machines_running = 0
  processes = ['app']

[[vm]]
  memory = '256mb'
  cpu_kind = 'shared'
  cpus = 1

Dockerfile

FROM golang:1.22-alpine

WORKDIR /app
COPY . .

RUN go mod download

RUN CGO_ENABLED=0 GOOS=linux go build -o main ./cmd/main.go

CMD ["/app/main"]

Deploy app

fly deploy

Check status

fly status
fly logs

Automatic Deployment with Github

Create config file in your workdir: .github/workflows/fly.yml
This would be created automatically when you run fly deploy for the first time

name: Fly Deploy
on:
  push:
    branches:
      - main

jobs:
  deploy:
    name: Deploy app
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - uses: superfly/flyctl-actions/setup-flyctl@master

      - name: Deploy to fly.io
        run: flyctl deploy --remote-only
        env:
          FLY_API_TOKEN: ${{ secrets.FLY_API_TOKEN }}

Get your token

fly auth token

Add Github Secret

Go to Settings > Secrets and variables > Actions
Create FLY_API_TOKEN
Paste token

The app will now auto-deploy on push to main branch

Add Multiple Services

Directory as blow:

.
├── service-1
├── service-2
├── service-3
├── Dockerfile
├── fly.toml
├── Caddyfile

Here use Caddy as reverse proxy

Create Dockerfile for Multiple Services

FROM golang:1.22-alpine AS go-builder

# service-1
WORKDIR /app/service-1
COPY ./service-1 .
RUN go mod download
RUN go build -o main ./cmd/main.go

# service-2
WORKDIR /app/service-2
COPY ./service-2 .
RUN go mod download
RUN go build -o main ./cmd/main.go

# service-3
FROM maven:3.8-openjdk-17-slim AS java-builder
WORKDIR /app/service-3
COPY ./service-3 .
RUN mvn clean package -DskipTests


# caddy
FROM caddy:2.7-alpine

# Install JRE for running the Java application
RUN apk add --no-cache openjdk17-jre

COPY ./Caddyfile /etc/caddy/Caddyfile

# go builder
COPY --from=go-builder /app/service-1/main /usr/local/bin/service-1
COPY --from=go-builder /app/service-2/main /usr/local/bin/service-2

# java builder
COPY --from=java-builder /app/service-3/target/*.jar /usr/local/bin/service-3.jar

# start script
RUN printf '#!/bin/sh\nservice-1 &\nservice-2 &\njava -jar /usr/local/bin/service-3.jar &\ncaddy run --config /etc/caddy/Caddyfile\n' > /usr/local/bin/start.sh

RUN chmod +x /usr/local/bin/start.sh
RUN chmod +x /usr/local/bin/service-1
RUN chmod +x /usr/local/bin/service-2

EXPOSE 7070

CMD ["/usr/local/bin/start.sh"]

start.sh:

service-1 &
service-2 &
java -jar /usr/local/bin/service-3.jar &
caddy run --config /etc/caddy/Caddyfile

Create Caddyfile

:7070 {
    # service-1
    handle /service-1/* {
        # remove /service-1 from the request
        uri strip_prefix /service-1
        reverse_proxy localhost:7071
    }

    # service-2
    handle /service-2/* {
        uri strip_prefix /service-2
        reverse_proxy localhost:7072
    }

    # service-3
    handle /service-3/* {
        uri strip_prefix /service-3
        reverse_proxy localhost:7073
    }

    # homepage
    handle / {
        respond "NO CONTENT" 200
    }

    log {
        output stdout
    }
}

Other Configurations

Redis

Create Redis instance

fly redis create
# get Redis URL，e.g. redis://default:password@redis.xxx.fly.dev:6379
# xxx is probably your app name

Set environmental variables

fly secrets set REDIS_URL='redis://default:password@redis.xxx.fly.dev:6379'
fly secrets set OTHER_ENV_VAR='value'

PostgreSQL

Create PostgreSQL instance

fly postgres create --name dbname-db --region nrt

Attach to your app

fly postgres attach --app your-app-name dbname-db

This will return infomation like below:

DATABASE_URL=postgres://dbname_user:randompassword@dbname-db.flycast:5432/dbname_db?sslmode=disable

Set the environmental variable Use Spring boot as example

spring.datasource.url=jdbc:postgresql://dbname-db.flycast:5432/dbname_db?sslmode=disable
spring.datasource.username=dbname_user
spring.datasource.password=randompassword

Deploy
Docker file is in the previous section (Multiple Services)
Modify the start.sh as below

#!/bin/sh

set -e

# Wait for database to be available
echo "Waiting for database to be available..."
until pg_isready -d "$DATABASE_URL"; do
  echo "Database is unavailable - sleeping"
  sleep 2
done
echo "Database is up!"

# Execute SQL initialization script
echo "Executing init.sql script..."
psql "$DATABASE_URL" -f /app/init.sql

# Start Java service
echo "Starting service-3..."
java -jar /usr/local/bin/service-3.jar &

# Start Go service
echo "Starting service-1..."
service-1 &

echo "Starting service-2..."
service-2 &

# Start Caddy as a foreground process
echo "Starting Caddy web server..."
caddy run --config /etc/caddy/Caddyfile

Deploy

fly deploy

Deploy Multiple Services App by fly.io (Java/Golang)

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