If you have ever tried getting Let's Encrypt certificate for Spring Boot application, you know that it is painful as it involves using either CertBot or Docker-sidecar/Cron-job to manage certificate lifecycle, especially if it is small pet application. This library solves these problems by managing certificate lifecycle directly in Java code with the help of awesome Acme4j library.

Note: This version is for Spring Boot 3.x and Spring 6.x, for older Spring/Spring Boot versions see Release 0.2.5

1. Obtain Let's Encrypt certificate on fresh start (or from other ACME compliant certificate provider)
2. Store generated keys and certificate into single KeyStore (server.ssl.keystore)
3. Renew Let's Encrypt certificate (it watches for certificate expiration date and updates it to new before old is expired)
4. No JVM restart needed when certificate gets updated

To perform HTTP-01 ACME (Automatic Certificate Management Environment) challenge, the application must listen on port 80, this library will automatically create Tomcat connector to this port, so the only thing needed on your side is to open 80 port for the application.

• Tomcat
• Jetty

 allprojects {
     repositories {
         ...
         maven { url 'https://jitpack.io' }
     }
 }

dependencies {
   implementation 'com.github.valb3r.letsencrypt-helper:letsencrypt-helper-tomcat:0.4.0'
}

<repositories>
     <repository>
         <id>jitpack.io</id>
         <url>https://jitpack.io</url>
     </repository>
 </repositories>

<dependencies>
   <dependency>
      <groupId>com.github.valb3r.letsencrypt-helper</groupId>
      <artifactId>letsencrypt-helper-tomcat</artifactId>
      <version>0.4.0</version>
   </dependency>
</dependencies>

 allprojects {
     repositories {
         ...
         maven { url 'https://jitpack.io' }
     }
 }

dependencies {
   implementation 'com.github.valb3r.letsencrypt-helper:letsencrypt-helper-jetty:0.4.0'
}

<repositories>
     <repository>
         <id>jitpack.io</id>
         <url>https://jitpack.io</url>
     </repository>
 </repositories>

<dependencies>
   <dependency>
      <groupId>com.github.valb3r.letsencrypt-helper</groupId>
      <artifactId>letsencrypt-helper-jetty</artifactId>
      <version>0.4.0</version>
   </dependency>
</dependencies>

@Import(TomcatWellKnownLetsEncryptChallengeEndpointConfig.class)

@Import(JettyWellKnownLetsEncryptChallengeEndpointConfig.class)

1. lets-encrypt-helper.domain the domain to issue certificate for
2. lets-encrypt-helper.contact your contact for Let's Encrypt (i.e. your email in format mailto:[email protected])

Launch your application with -Dspring.profiles.active=ssl

application-ssl.yaml:

server:
  port: 443
  ssl:
    key-store: file:/home/user/letsencrypt/application-keystore # Path to KeyStore with certificates and keys
    key-store-password: change-me # Password for KeyStore protection
    key-store-type: PKCS12
    key-alias: tomcat # Certificate name in KeyStore
    enabled: true # Important to place this explicitly
lets-encrypt-helper:
  domain: my-domain.example.com # Domain to issue certificate for
  contact: mailto:[email protected] # Your contact for Let's Encrypt

Note: On your server ensure you have opened port 80 for Java (i.e. in Firewall) and Java can bind to it (i.e. follow Linux allow listening to low port without sudo to open ports 80,443 for java)

Example project with SSL and Let's Encrypt management using this library is located here

The library is itself just 1 Java class. You can add library dependencies and:

• For Tomcat this java file to your configuration
• For Jetty this java file to your configuration

The library has integration tests in:

• tomcat/src/test/java
• jetty/src/test/java

directories. One can adapt these tests according to own needs, as they use Pebble - LetsEncrypt testing server.