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Deploy Spring Boot on DCDeploy

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Quick Start: Hello World

1. Create a new Spring Boot project (using Spring Initializr or CLI):
   Copy

   curl https://start.spring.io/starter.zip \
     -d dependencies=web \
     -d language=java \
     -d name=hello-dcdeploy \
     -o hello-dcdeploy.zip
   unzip hello-dcdeploy.zip
   cd hello-dcdeploy
   

2. Modify src/main/java/com/example/demo/DemoApplication.java:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
public class DemoApplication {
  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }
}

@RestController
class HelloController {
  @GetMapping("/")
  public String hello() {
    return "Hello DCDeploy from Spring Boot!";
  }
}

3. Add a Dockerfile (if using Docker for deployment) or prepare the build to be invoked by DCDeploy.
4. Push the code to a Git repository.
5. Deploy on DCDeploy using the steps in this guide.

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Overview

• Build from Code (auto-detecting Java/Maven/Gradle projects)
• Dockerfile, for full control (custom JVM options, multi-stage builds)

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Prerequisites

• Java 17+ or appropriate version for your app.
• Build tool: Maven or Gradle in your repo.
• pom.xml or build.gradle describing dependencies.
• A Git repository.
• If using Docker, include a Dockerfile.
• Application should read port from environment (e.g. $ or fallback) and listen on 0.0.0.0.

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Step-by-Step Guide

1. Prepare Your Spring Boot App

• Ensure your main class (with @SpringBootApplication) is correctly set.
• Update application.properties or application.yml to use environment variables:

server.port=${PORT:8080}
spring.datasource.url=${DATABASE_URL}
spring.datasource.username=${DB_USER}
spring.datasource.password=${DB_PASS}

2. Add Dockerfile (optional but often preferred) Example Dockerfile with multi-stage build:

# Build stage
FROM maven:3.9.0-openjdk-17-slim AS build
WORKDIR /app
COPY pom.xml .
COPY src ./src
RUN mvn clean package -DskipTests

# Runtime stage
FROM openjdk:17-slim
WORKDIR /app
COPY --from=build /app/target/*.jar ./app.jar
EXPOSE 8080
ENTRYPOINT ["java","-jar","app.jar"]

3. Push Code to Git

• Initialize Git if needed, commit all files.
• If using .gitignore, exclude target/, .mvn/, .settings, etc.

4. Deploy on DCDeploy

• In DCDeploy dashboard → go to your environment → Deploy tab.
• Add a new service → choose Build from Code or Docker Registry.
• Provide repo + branch.
• Set port to 8080 (or configured port), ensure the app listens on 0.0.0.0.
• Choose protocol (HTTP/HTTPS), region(s).
• Provide environment variables:
• DATABASE_URL, DB_USER, DB_PASS etc.
• SPRING_PROFILES_ACTIVE if you use profiles.
• Choose machine type (CPU/RAM) based on expected load.
• Set scaling parameters (minScale / maxScale).
• Deploy and monitor build & deployment logs.

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Example Service Configuration

services:
  spring-boot-app:
    build:
      context: ./
      dockerfilePath: ./Dockerfile
      repo: your-username/hello-spring-boot
      ref: main
      refType: branch
      autoBuild: true
    ports:
      - 8080
    protocol: https
    minScale: 1
    maxScale: 2
    environment:
      DATABASE_URL: "jdbc:postgresql://db.internal:5432/mydb"
      DB_USER: "username"
      DB_PASS: "password"
      SPRING_PROFILES_ACTIVE: "prod"

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Best Practices

• Use multi-stage Docker builds to reduce image size.
• Set server.port dynamically via $ environment variable.
• Use internal networking for databases and other services inside DCDeploy.
• Use health checks (for example /actuator/health) to allow DCDeploy to monitor readiness.
• Configure logging and monitoring.
• Use secrets instead of hard-coded credentials.

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Troubleshooting