Add Configuration.refresh() for manual refreshing of ConfigurationSou…

…rce plugins

avaje-aws-appconfig/src/main/java/io/avaje/config/awsappconfig/AwsAppConfigPlugin.java

@@ -5,7 +5,10 @@
 import io.avaje.config.ConfigurationSource;
 
 import java.io.StringReader;
+import java.time.Instant;
 import java.util.Map;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.ReentrantLock;
 
 import static java.lang.System.Logger.Level.*;
 
@@ -18,30 +21,40 @@ public final class AwsAppConfigPlugin implements ConfigurationSource {
 
   private static final System.Logger log = System.getLogger("io.avaje.config.AwsAppConfig");
 
+  private Loader loader;
+
   @Override
   public void load(Configuration configuration) {
     if (!configuration.enabled("aws.appconfig.enabled", true)) {
       log.log(INFO, "AwsAppConfig plugin is disabled");
       return;
     }
-    var loader = new Loader(configuration);
-    loader.schedule();
+    loader = new Loader(configuration);
     loader.reload();
   }
 
+  @Override
+  public void refresh() {
+    if (loader != null) {
+      loader.reload();
+    }
+  }
+
   static final class Loader {
 
     private final Configuration configuration;
     private final AppConfigFetcher fetcher;
     private final ConfigParser yamlParser;
     private final ConfigParser propertiesParser;
-    private final long frequency;
+    private final ReentrantLock lock = new ReentrantLock();
+    private final AtomicReference<Instant> validUntil;
+    private final long nextRefreshSeconds;
 
     private String currentVersion = "none";
 
     Loader(Configuration configuration) {
+      this.validUntil = new AtomicReference<>(Instant.now().minusSeconds(1));
       this.configuration = configuration;
-      this.frequency = configuration.getLong("aws.appconfig.frequency", 60L);
       this.propertiesParser = configuration.parser("properties").orElseThrow();
       this.yamlParser = configuration.parser("yaml").orElse(null);
       if (yamlParser == null) {
@@ -57,14 +70,31 @@ static final class Loader {
         .environment(env)
         .configuration(con)
         .build();
-    }
 
-    void schedule() {
-      configuration.schedule(frequency * 1000L, frequency * 1000L, this::reload);
+      boolean pollEnabled = configuration.enabled("aws.appconfig.poll.enabled", true);
+      long pollSeconds = configuration.getLong("aws.appconfig.poll.seconds", 45L);
+      this.nextRefreshSeconds = configuration.getLong("aws.appconfig.refresh.seconds", pollSeconds - 1);
+      if (pollEnabled) {
+        configuration.schedule(pollSeconds * 1000L, pollSeconds * 1000L, this::reload);
+      }
     }
 
     void reload() {
+      if (reloadRequired()) {
+        performReload();
+      }
+    }
+
+    private boolean reloadRequired() {
+      return validUntil.get().isAfter(Instant.now());
+    }
+
+    private void performReload() {
+      lock.lock();
       try {
+        if (!reloadRequired()) {
+          return;
+        }
         AppConfigFetcher.Result result = fetcher.fetch();
         if (currentVersion.equals(result.version())) {
           log.log(TRACE, "AwsAppConfig unchanged, version {0}", currentVersion);
@@ -75,14 +105,18 @@ void reload() {
           }
           Map<String, String> keyValues = parse(result);
           configuration.eventBuilder("AwsAppConfig")
-              .putAll(keyValues)
-              .publish();
+            .putAll(keyValues)
+            .publish();
           currentVersion = result.version();
           debugLog(result, keyValues.size());
         }
+        // move the next valid until time
+        validUntil.set(Instant.now().plusSeconds(nextRefreshSeconds));
 
       } catch (Exception e) {
         log.log(ERROR, "Error fetching or processing AwsAppConfig", e);
+      } finally {
+        lock.unlock();
       }
     }
 

avaje-config/src/main/java/io/avaje/config/Configuration.java

@@ -482,6 +482,15 @@ default boolean enabled(String key, boolean enabledDefault) {
    */
   void loadIntoSystemProperties();
 
+  /**
+   * Trigger a refresh on all {@link ConfigurationSource}.
+   * <p>
+   * Generally configuration sources will schedule a periodic refresh of their
+   * configuration but there are cases like Lambda where it can be useful to
+   * trigger a refresh explicitly (e.g. on Lambda invocation).
+   */
+  void refresh();
+
   /**
    * Return the number of configuration properties.
    */

avaje-config/src/main/java/io/avaje/config/ConfigurationSource.java

@@ -23,4 +23,15 @@ public interface ConfigurationSource {
    * @param configuration The configuration with initially properties.
    */
   void load(Configuration configuration);
+
+  /**
+   * Explicitly refresh the configuration source.
+   * <p>
+   * Generally the configuration source will schedule a periodic refresh of its
+   * configuration but there are cases like Lambda where it can be useful to
+   * trigger a refresh explicitly and manually (e.g. on Lambda invocation).
+   */
+  default void refresh() {
+    // do nothing by default
+  }
 }

avaje-config/src/main/java/io/avaje/config/CoreComponents.java

@@ -0,0 +1,42 @@
+package io.avaje.config;
+
+import java.util.Collections;
+import java.util.List;
+
+final class CoreComponents {
+
+  private final ModificationEventRunner runner;
+  private final ConfigurationLog log;
+  private final Parsers parsers;
+  private final List<ConfigurationSource> sources;
+
+  CoreComponents(ModificationEventRunner runner, ConfigurationLog log, Parsers parsers, List<ConfigurationSource> sources) {
+    this.runner = runner;
+    this.log = log;
+    this.parsers = parsers;
+    this.sources = sources;
+  }
+
+  CoreComponents() {
+    this.runner = new CoreConfiguration.ForegroundEventRunner();
+    this.log = new DefaultConfigurationLog();
+    this.parsers = new Parsers();
+    this.sources = Collections.emptyList();
+  }
+
+  Parsers parsers() {
+    return parsers;
+  }
+
+  ConfigurationLog log() {
+    return log;
+  }
+
+  ModificationEventRunner runner() {
+    return runner;
+  }
+
+  List<ConfigurationSource> sources() {
+    return sources;
+  }
+}

avaje-config/src/main/java/io/avaje/config/CoreConfiguration.java

@@ -36,16 +36,18 @@ final class CoreConfiguration implements Configuration {
   private final CoreListValue listValue;
   private final CoreSetValue setValue;
   private final ModificationEventRunner eventRunner;
+  private final List<ConfigurationSource> sources;
 
   private boolean loadedSystemProperties;
   private FileWatch watcher;
   private Timer timer;
   private final String pathPrefix;
 
-  CoreConfiguration(Parsers parsers, ModificationEventRunner eventRunner, ConfigurationLog log, CoreEntry.CoreMap entries) {
-    this.parsers = parsers;
-    this.eventRunner = eventRunner;
-    this.log = log;
+  CoreConfiguration(CoreComponents components, CoreEntry.CoreMap entries) {
+    this.parsers = components.parsers();
+    this.eventRunner = components.runner();
+    this.log = components.log();
+    this.sources = components.sources();
     this.properties = new ModifyAwareProperties(entries);
     this.listValue = new CoreListValue(this);
     this.setValue = new CoreSetValue(this);
@@ -56,6 +58,7 @@ final class CoreConfiguration implements Configuration {
     this.parsers = parent.parsers;
     this.eventRunner = parent.eventRunner;
     this.log = parent.log;
+    this.sources = parent.sources;
     this.properties = new ModifyAwareProperties(entries);
     this.listValue = new CoreListValue(this);
     this.setValue = new CoreSetValue(this);
@@ -66,7 +69,7 @@ final class CoreConfiguration implements Configuration {
    * For testing purposes.
    */
   CoreConfiguration(CoreEntry.CoreMap entries) {
-    this(new Parsers(), new ForegroundEventRunner(), new DefaultConfigurationLog(), entries);
+    this(new CoreComponents(), entries);
   }
 
   /**
@@ -108,7 +111,7 @@ void initSystemProperties() {
   }
 
   private void loadSources(Set<String> names) {
-    for (final ConfigurationSource source : ServiceLoader.load(ConfigurationSource.class)) {
+    for (ConfigurationSource source : sources) {
       source.load(this);
       names.add("ConfigurationSource:" + source.getClass().getCanonicalName());
     }
@@ -174,6 +177,13 @@ public void loadIntoSystemProperties() {
     loadedSystemProperties = true;
   }
 
+  @Override
+  public void refresh() {
+    for (ConfigurationSource source : sources) {
+      source.refresh();
+    }
+  }
+
   @Override
   public Properties asProperties() {
     return properties.asProperties();

avaje-config/src/main/java/io/avaje/config/CoreConfigurationBuilder.java

@@ -1,9 +1,7 @@
 package io.avaje.config;
 
-import java.util.LinkedHashMap;
-import java.util.Map;
-import java.util.Properties;
-import java.util.ServiceLoader;
+import java.util.*;
+import java.util.stream.Collectors;
 
 import static java.util.Objects.requireNonNull;
 
@@ -76,11 +74,16 @@ public Configuration build() {
     final var runner = initRunner();
     final var log = initLog();
     final var parsers = new Parsers();
+    final var sources = ServiceLoader.load(ConfigurationSource.class).stream()
+      .map(ServiceLoader.Provider::get)
+      .collect(Collectors.toList());
+
+    var components = new CoreComponents(runner, log, parsers, sources);
     if (includeResourceLoading) {
       log.preInitialisation();
-      initialLoader = new InitialLoader(parsers, log, initResourceLoader());
+      initialLoader = new InitialLoader(components, initResourceLoader());
     }
-    return new CoreConfiguration(parsers, runner, log, initEntries()).postLoad(initialLoader);
+    return new CoreConfiguration(components, initEntries()).postLoad(initialLoader);
   }
 
   private CoreEntry.CoreMap initEntries() {

avaje-config/src/main/java/io/avaje/config/InitialLoader.java

@@ -41,9 +41,9 @@ enum Source {
   private final Set<String> profileResourceLoaded = new HashSet<>();
   private final Parsers parsers;
 
-  InitialLoader(Parsers parsers, ConfigurationLog log, ResourceLoader resourceLoader) {
-    this.parsers = parsers;
-    this.log = log;
+  InitialLoader(CoreComponents components, ResourceLoader resourceLoader) {
+    this.parsers = components.parsers();
+    this.log = components.log();
     this.loadContext = new InitialLoadContext(log, resourceLoader);
   }
 

avaje-config/src/test/java/io/avaje/config/CoreConfigurationTest.java

@@ -1,6 +1,7 @@
 package io.avaje.config;
 
 import io.avaje.config.CoreEntry.CoreMap;
+import org.example.MyExternalLoader;
 import org.junit.jupiter.api.Test;
 
 import java.io.StringReader;
@@ -177,6 +178,10 @@ void builder_withResources() {
 
     String userHome = System.getProperty("user.home");
     assertThat(conf.get("myHome")).isEqualTo("my/" + userHome + "/home");
+
+    MyExternalLoader.reset();
+    conf.refresh();
+    assertThat(MyExternalLoader.refreshCalled()).isTrue();
   }
 
   @Test

avaje-config/src/test/java/io/avaje/config/InitialLoaderTest.java

@@ -10,7 +10,7 @@
 class InitialLoaderTest {
 
   private static InitialLoader newInitialLoader() {
-    return new InitialLoader(new Parsers(), new DefaultConfigurationLog(), new DefaultResourceLoader());
+    return new InitialLoader(new CoreComponents(), new DefaultResourceLoader());
   }
 
   @Test

avaje-config/src/test/java/org/example/MyExternalLoader.java

@@ -5,6 +5,8 @@
 
 public class MyExternalLoader implements ConfigurationSource {
 
+  static boolean refreshCalled;
+
   @Override
   public void load(Configuration configuration) {
 
@@ -19,4 +21,16 @@ public void load(Configuration configuration) {
     configuration.schedule(500, 500, () -> System.out.println("MyExternalLoader task .."));
   }
 
+  @Override
+  public void refresh() {
+    refreshCalled = true;
+  }
+
+  public static boolean refreshCalled() {
+    return refreshCalled;
+  }
+
+  public static void reset() {
+    refreshCalled = false;
+  }
 }