Periodic TLS certificate reload

Provide a way to periodically reload certificates from the file system and document how to implement your own reloader.

docs/src/main/asciidoc/tls-registry-reference.adoc

@@ -519,3 +519,64 @@ When the application starts, the TLS registry performs some checks to ensure the
 - the CRLs are valid
 
 If any of these checks fail, the application will fail to start.
+
+== Reloading Certificates
+
+The `TlsConfiguration` obtained from the `TLSConfigurationRegistry` includes a mechanism for reloading certificates.
+The `reload` method refreshes the key stores and trust stores, typically by reloading them from the file system.
+
+NOTE: The reload operation is not automatic and must be triggered manually. Additionally, the `TlsConfiguration` implementation must support reloading (which is the case for the configured certificate).
+
+The `reload` method returns a `boolean` indicating whether the reload was successful.
+A value of `true` means the reload operation was successful, not necessarily that there were updates to the certificates.
+
+After a `TlsConfiguration` has been reloaded, servers and clients using this configuration may need to perform specific actions to apply the new certificates.
+The recommended approach is to fire a CDI event (`CertificateReloadedEvent`) that servers and clients can listen to and make the necessary changes:
+
+[source, java]
+----
+@Inject
+TlsConfigurationRegistry registry;
+
+public void reload() {
+    TlsConfiguration config = registry.get("name").orElseThrow();
+    if (config.reload()) {
+        event.fire(new CertificateReloadedEvent("name", config));
+    }
+}
+
+// In the server or client code
+public void onReload(@Observes CertificateReloadedEvent event) {
+    if ("name".equals(event.getName())) {
+        server.updateSSLOptions(event.tlsConfiguration().getSSLOptions());
+        // Or update the SSLContext.
+    }
+}
+----
+
+These APIs provide a way to implement custom certificate reloading.
+
+=== Periodic reloading
+
+The TLS registry does include a built-in mechanism for periodically checking the file system for changes and reloading the certificates.
+You can configure periodic reloading of certificates using properties.
+The `reload-period` property specifies the interval at which certificates are reloaded, and it will emit a `CertificateReloadedEvent`.
+
+[source, properties]
+----
+quarkus.tls.reload-period=1h
+quarkus.tls.key-store.pem.0.cert=tls.crt
+quarkus.tls.key-store.pem.0.key=tls.key
+----
+
+For each named configuration, you can set a specific reload period:
+
+[source, properties]
+----
+quarkus.tls.http.reload-period=30min
+quarkus.tls.http.key-store.pem.0.cert=tls.crt
+quarkus.tls.http.key-store.pem.0.key=tls.key
+----
+
+Remember that the impacted server and client may need to listen to the `CertificateReloadedEvent` to apply the new certificates.
+This is automatically done for the Quarkus HTTP server (including the management interface if enabled).

extensions/tls-registry/deployment/src/main/java/io/quarkus/tls/CertificatesProcessor.java

@@ -11,6 +11,7 @@
 import io.quarkus.deployment.annotations.BuildStep;
 import io.quarkus.deployment.annotations.ExecutionTime;
 import io.quarkus.deployment.annotations.Record;
+import io.quarkus.deployment.builditem.ShutdownContextBuildItem;
 import io.quarkus.tls.runtime.CertificateRecorder;
 import io.quarkus.tls.runtime.config.TlsConfig;
 import io.quarkus.vertx.deployment.VertxBuildItem;
@@ -22,10 +23,11 @@ public class CertificatesProcessor {
     public TlsRegistryBuildItem initializeCertificate(
             TlsConfig config, Optional<VertxBuildItem> vertx, CertificateRecorder recorder,
             BuildProducer<SyntheticBeanBuildItem> syntheticBeans,
-            List<TlsCertificateBuildItem> otherCertificates) {
+            List<TlsCertificateBuildItem> otherCertificates,
+            ShutdownContextBuildItem shutdown) {
 
         if (vertx.isPresent()) {
-            recorder.validateCertificates(config, vertx.get().getVertx());
+            recorder.validateCertificates(config, vertx.get().getVertx(), shutdown);
         }
 
         for (TlsCertificateBuildItem certificate : otherCertificates) {

extensions/tls-registry/runtime/src/main/java/io/quarkus/tls/CertificateUpdatedEvent.java

@@ -0,0 +1,14 @@
+package io.quarkus.tls;
+
+/**
+ * Event fired when a certificate is updated.
+ * <p>
+ * IMPORTANT: Consumers of this event should be aware that the event is fired from a blocking context (worker thread),
+ * and thus can perform blocking operations.
+ *
+ * @param name the name of the certificate (as configured in the configuration, {@code <default>} for the default certificate)
+ * @param tlsConfiguration the updated TLS configuration - the certificate has already been updated
+ */
+public record CertificateUpdatedEvent(String name, TlsConfiguration tlsConfiguration) {
+
+}

extensions/tls-registry/runtime/src/main/java/io/quarkus/tls/runtime/CertificateRecorder.java

@@ -8,6 +8,7 @@
 import java.util.function.Supplier;
 
 import io.quarkus.runtime.RuntimeValue;
+import io.quarkus.runtime.ShutdownContext;
 import io.quarkus.runtime.annotations.Recorder;
 import io.quarkus.tls.TlsConfiguration;
 import io.quarkus.tls.TlsConfigurationRegistry;
@@ -25,6 +26,7 @@
 public class CertificateRecorder implements TlsConfigurationRegistry {
 
     private final Map<String, TlsConfiguration> certificates = new ConcurrentHashMap<>();
+    private volatile TlsCertificateUpdater reloader;
 
     /**
      * Validate the certificate configuration.
@@ -35,7 +37,7 @@ public class CertificateRecorder implements TlsConfigurationRegistry {
      * @param config the configuration
      * @param vertx the Vert.x instance
      */
-    public void validateCertificates(TlsConfig config, RuntimeValue<Vertx> vertx) {
+    public void validateCertificates(TlsConfig config, RuntimeValue<Vertx> vertx, ShutdownContext shutdownContext) {
         // Verify the default config
         if (config.defaultCertificateConfig().isPresent()) {
             verifyCertificateConfig(config.defaultCertificateConfig().get(), vertx.getValue(), TlsConfig.DEFAULT_NAME);
@@ -45,6 +47,15 @@ public void validateCertificates(TlsConfig config, RuntimeValue<Vertx> vertx) {
         for (String name : config.namedCertificateConfig().keySet()) {
             verifyCertificateConfig(config.namedCertificateConfig().get(name), vertx.getValue(), name);
         }
+
+        shutdownContext.addShutdownTask(new Runnable() {
+            @Override
+            public void run() {
+                if (reloader != null) {
+                    reloader.close();
+                }
+            }
+        });
     }
 
     public void verifyCertificateConfig(TlsBucketConfig config, Vertx vertx, String name) {
@@ -55,7 +66,7 @@ public void verifyCertificateConfig(TlsBucketConfig config, Vertx vertx, String
             KeyStoreConfig keyStoreConfig = config.keyStore().get();
             ks = verifyKeyStore(keyStoreConfig, vertx, name);
             sni = keyStoreConfig.sni();
-            if (sni) {
+            if (sni && ks != null) {
                 try {
                     if (Collections.list(ks.keyStore.aliases()).size() <= 1) {
                         throw new IllegalStateException(
@@ -81,6 +92,14 @@ public void verifyCertificateConfig(TlsBucketConfig config, Vertx vertx, String
         }
 
         certificates.put(name, new VertxCertificateHolder(vertx, name, config, ks, ts));
+
+        // Handle reloading if needed
+        if (config.reloadPeriod().isPresent()) {
+            if (reloader == null) {
+                reloader = new TlsCertificateUpdater(vertx);
+            }
+            reloader.add(name, certificates.get(name), config.reloadPeriod().get());
+        }
     }
 
     public static KeyStoreAndKeyCertOptions verifyKeyStore(KeyStoreConfig config, Vertx vertx, String name) {

extensions/tls-registry/runtime/src/main/java/io/quarkus/tls/runtime/TlsCertificateUpdater.java

@@ -0,0 +1,61 @@
+package io.quarkus.tls.runtime;
+
+import java.time.Duration;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+import jakarta.enterprise.event.Event;
+import jakarta.enterprise.inject.spi.CDI;
+
+import io.quarkus.tls.CertificateUpdatedEvent;
+import io.quarkus.tls.TlsConfiguration;
+import io.vertx.core.Handler;
+import io.vertx.core.Vertx;
+
+/**
+ * A helper class that reload the TLS certificates at a configured interval.
+ * When the certificate is reloaded, a {@link CertificateUpdatedEvent} is fired.
+ */
+public class TlsCertificateUpdater {
+
+    private final Vertx vertx;
+    private final CopyOnWriteArrayList<Long> tasks;
+    private final Event<CertificateUpdatedEvent> event;
+
+    public TlsCertificateUpdater(Vertx vertx) {
+        this.vertx = vertx;
+        this.tasks = new CopyOnWriteArrayList<>();
+        this.event = CDI.current().getBeanManager().getEvent().select(CertificateUpdatedEvent.class);
+    }
+
+    public void close() {
+        for (Long task : tasks) {
+            vertx.cancelTimer(task);
+        }
+        tasks.clear();
+    }
+
+    public void add(String name, TlsConfiguration tlsConfiguration, Duration period) {
+        var id = vertx.setPeriodic(period.toMillis(), new Handler<Long>() {
+            @Override
+            public void handle(Long id) {
+                vertx.executeBlocking(new Callable<Void>() {
+                    @Override
+                    public Void call() {
+                        // Reload is most probably a blocking operation as it needs to reload the certificate from the
+                        // file system. Thus, it is executed in a blocking context.
+                        // Then we fire the event. This is also potentially blocking, as the consumer are invoked on the
+                        // same thread.
+                        if (tlsConfiguration.reload()) {
+                            event.fire(new CertificateUpdatedEvent(name, tlsConfiguration));
+                        }
+                        return null;
+                    }
+                }, false);
+            }
+        });
+
+        tasks.add(id);
+    }
+
+}

extensions/tls-registry/runtime/src/main/java/io/quarkus/tls/runtime/config/TlsBucketConfig.java

@@ -7,6 +7,7 @@
 import java.util.Set;
 
 import io.quarkus.runtime.annotations.ConfigGroup;
+import io.quarkus.tls.CertificateUpdatedEvent;
 import io.smallrye.config.WithDefault;
 
 @ConfigGroup
@@ -106,4 +107,19 @@ public interface TlsBucketConfig {
      */
     Optional<String> hostnameVerificationAlgorithm();
 
+    /**
+     * When configured, the server will reload the certificates (from the file system for example) and fires a
+     * {@link CertificateUpdatedEvent} if the reload is successful
+     * <p>
+     * This property configures the period to reload the certificates. IF not set, the certificates won't be reloaded
+     * automatically.
+     * However, the application can still trigger the reload manually using the {@link io.quarkus.tls.TlsConfiguration#reload()}
+     * method,
+     * and then fire the {@link CertificateUpdatedEvent} manually.
+     * <p>
+     * The fired event is used to notify the application that the certificates have been updated, and thus proceed with the
+     * actual switch of certificates.
+     */
+    Optional<Duration> reloadPeriod();
+
 }

extensions/vertx-http/deployment/src/main/java/io/quarkus/vertx/http/deployment/VertxHttpProcessor.java

@@ -68,6 +68,7 @@
 import io.quarkus.vertx.http.runtime.CurrentRequestProducer;
 import io.quarkus.vertx.http.runtime.CurrentVertxRequest;
 import io.quarkus.vertx.http.runtime.HttpBuildTimeConfig;
+import io.quarkus.vertx.http.runtime.HttpCertificateUpdateEventListener;
 import io.quarkus.vertx.http.runtime.HttpConfiguration;
 import io.quarkus.vertx.http.runtime.VertxConfigBuilder;
 import io.quarkus.vertx.http.runtime.VertxHttpRecorder;
@@ -171,6 +172,7 @@ AdditionalBeanBuildItem additionalBeans() {
                 .setUnremovable()
                 .addBeanClass(CurrentVertxRequest.class)
                 .addBeanClass(CurrentRequestProducer.class)
+                .addBeanClass(HttpCertificateUpdateEventListener.class)
                 .build();
     }