Spring Profiles & Configuration

Quick Start

@Configuration
@Profile("dev")
public class DevConfig {
    @Bean
    public DataSource dataSource() {
        return new EmbeddedDatabaseBuilder()
            .setType(EmbeddedDatabaseType.H2)
            .build();
    }
}

@Configuration
@Profile("prod")
public class ProdConfig {
    @Bean
    public DataSource dataSource() {
        HikariDataSource ds = new HikariDataSource();
        ds.setJdbcUrl(System.getenv("DATABASE_URL"));
        return ds;
    }
}

Profile Activation

# 1. application.yml
spring:
  profiles:
    active: dev

# 2. Environment variable: SPRING_PROFILES_ACTIVE=prod
# 3. Command line: java -jar app.jar --spring.profiles.active=prod
# 4. JVM property: java -Dspring.profiles.active=prod -jar app.jar

Profile Groups

spring:
  profiles:
    active: production
    group:
      production:
        - prod
        - prod-db
        - prod-security
      development:
        - dev
        - dev-db
        - dev-tools

Profile Expression

@Profile("cloud & kubernetes")  // AND
@Profile("dev | test")          // OR
@Profile("!prod")               // NOT
@Profile("(dev | test) & !integration")  // Combined

@ConfigurationProperties

@ConfigurationProperties(prefix = "app")
@Validated
public class AppProperties {

    @NotBlank
    private String name;

    @NotNull
    private String version;

    private final Security security = new Security();

    @Validated
    public static class Security {
        @NotBlank
        private String jwtSecret;

        @Min(3600)
        private long jwtExpiration = 86400;

        @NotEmpty
        private List<String> allowedOrigins = new ArrayList<>();
    }

    // Getters and setters
}

// Abilitazione
@Configuration
@EnableConfigurationProperties(AppProperties.class)
public class AppConfig {}

app:
  name: MyApplication
  version: 1.0.0
  security:
    jwt-secret: ${JWT_SECRET}
    jwt-expiration: 86400
    allowed-origins:
      - https://example.com

Immutable Configuration (Record)

@ConfigurationProperties(prefix = "app.mail")
public record MailProperties(
    @NotBlank String host,
    @Min(1) @Max(65535) int port,
    String username,
    @DefaultValue("false") boolean starttls
) {}

Full Reference: See properties.md for Property Sources, External Configuration (Config Server, K8s, Vault).

Conditional Beans

@Bean
@ConditionalOnProperty(name = "feature.email.enabled", havingValue = "true")
public EmailService emailService() {
    return new RealEmailService();
}

@Bean
@Profile("dev")
public CacheManager devCacheManager() {
    return new ConcurrentMapCacheManager();
}

@Bean
@ConditionalOnMissingBean(UserService.class)
public UserService defaultUserService() {
    return new DefaultUserService();
}

Full Reference: See conditional.md for Custom Conditions, Validation, Testing.

Secrets Management

spring:
  datasource:
    password: ${DB_PASSWORD}

app:
  security:
    jwt-secret: ${JWT_SECRET}

Full Reference: See secrets.md for Jasypt Encryption, Vault Integration.

Best Practices

| Do | Don't | |----|-------| | Use @ConfigurationProperties for structured config | Use @Value for complex config | | Validate properties with Bean Validation | Skip validation | | Use profile groups for complex environments | Duplicate configuration | | Externalize all secrets | Commit secrets to repository | | Use sensible default values | Require all properties |

Production Checklist

[ ] Secrets externalized (env vars, Vault)
[ ] Profiles configured for each environment
[ ] Validation enabled on all properties
[ ] Default values for optional properties
[ ] Profile groups for related config
[ ] Configuration encrypted where needed

When NOT to Use This Skill

Runtime feature flags - Consider LaunchDarkly, Flipt
Centralized config - Use spring-cloud-config skill
Secrets only - Consider HashiCorp Vault directly

Anti-Patterns

| Anti-Pattern | Problem | Solution | |--------------|---------|----------| | Secrets in git | Security vulnerability | Use env vars or secrets manager | | Wrong prefix | Properties not loaded | Verify prefix matches YAML | | Missing @Validated | Validation ignored | Add @Validated annotation | | @Value for complex config | Unmaintainable | Use @ConfigurationProperties |

Quick Troubleshooting

| Problem | Diagnostic | Fix | |---------|------------|-----| | Properties not loaded | Check prefix | Verify @ConfigurationProperties prefix | | Profile not active | Check logs at startup | Set spring.profiles.active | | Binding failed | Check type | Use correct types (Duration, etc.) | | Env var not resolved | Check naming | Use UPPER_SNAKE_CASE |

Reference Files

| File | Content | |------|---------| | properties.md | Property Sources, External Configuration | | conditional.md | Conditional Beans, Validation, Testing | | secrets.md | Secrets Management, Encryption |

spring-profiles