Add a manager class for checking "liveness" of client versions

service/src/main/java/org/whispersystems/textsecuregcm/storage/ClientReleaseManager.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.storage;
+
+import com.vdurmont.semver4j.Semver;
+import java.time.Clock;
+import java.time.Duration;
+import java.util.Collections;
+import java.util.Map;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import io.dropwizard.lifecycle.Managed;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.whispersystems.textsecuregcm.util.ua.ClientPlatform;
+import javax.annotation.Nullable;
+
+public class ClientReleaseManager implements Managed {
+
+  private final ClientReleases clientReleases;
+  private final ScheduledExecutorService scheduledExecutorService;
+  private final Duration refreshInterval;
+  private final Clock clock;
+
+  @Nullable
+  private ScheduledFuture<?> refreshClientReleasesFuture;
+
+  private volatile Map<ClientPlatform, Map<Semver, ClientRelease>> clientReleasesByPlatform = Collections.emptyMap();
+
+  private static final Logger logger = LoggerFactory.getLogger(ClientReleaseManager.class);
+
+  public ClientReleaseManager(final ClientReleases clientReleases,
+      final ScheduledExecutorService scheduledExecutorService,
+      final Duration refreshInterval,
+      final Clock clock) {
+
+    this.clientReleases = clientReleases;
+    this.scheduledExecutorService = scheduledExecutorService;
+    this.refreshInterval = refreshInterval;
+    this.clock = clock;
+  }
+
+  public boolean isVersionActive(final ClientPlatform platform, final Semver version) {
+    final Map<Semver, ClientRelease> releasesByVersion = clientReleasesByPlatform.get(platform);
+
+    return releasesByVersion != null &&
+        releasesByVersion.containsKey(version) &&
+        releasesByVersion.get(version).expiration().isAfter(clock.instant());
+  }
+
+  @Override
+  public void start() throws Exception {
+    refreshClientVersions();
+
+    refreshClientReleasesFuture =
+        scheduledExecutorService.scheduleWithFixedDelay(this::refreshClientVersions,
+            refreshInterval.toMillis(),
+            refreshInterval.toMillis(),
+            TimeUnit.MILLISECONDS);
+  }
+
+  @Override
+  public void stop() throws Exception {
+    if (refreshClientReleasesFuture != null) {
+      refreshClientReleasesFuture.cancel(true);
+    }
+  }
+
+  void refreshClientVersions() {
+    try {
+      clientReleasesByPlatform = clientReleases.getClientReleases();
+    } catch (final Exception e) {
+      logger.warn("Failed to refresh client releases", e);
+    }
+  }
+}

service/src/test/java/org/whispersystems/textsecuregcm/storage/ClientReleaseManagerTest.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.storage;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import com.vdurmont.semver4j.Semver;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.util.Map;
+import java.util.concurrent.ScheduledExecutorService;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.whispersystems.textsecuregcm.util.ua.ClientPlatform;
+
+class ClientReleaseManagerTest {
+
+  private ClientReleases clientReleases;
+  private Clock clock;
+
+  private ClientReleaseManager clientReleaseManager;
+
+  @BeforeEach
+  void setUp() {
+    clientReleases = mock(ClientReleases.class);
+    clock = Clock.fixed(Instant.now(), ZoneId.systemDefault());
+
+    clientReleaseManager =
+        new ClientReleaseManager(clientReleases, mock(ScheduledExecutorService.class), Duration.ofHours(4), clock);
+  }
+
+  @Test
+  void isVersionActive() {
+    final Semver iosVersion = new Semver("1.2.3");
+    final Semver desktopVersion = new Semver("4.5.6");
+
+    when(clientReleases.getClientReleases()).thenReturn(Map.of(
+        ClientPlatform.DESKTOP, Map.of(desktopVersion, new ClientRelease(ClientPlatform.DESKTOP, desktopVersion, clock.instant(), clock.instant().plus(Duration.ofDays(90)))),
+        ClientPlatform.IOS, Map.of(iosVersion, new ClientRelease(ClientPlatform.IOS, iosVersion, clock.instant().minus(Duration.ofDays(91)), clock.instant().minus(Duration.ofDays(1))))
+    ));
+
+    clientReleaseManager.refreshClientVersions();
+
+    assertTrue(clientReleaseManager.isVersionActive(ClientPlatform.DESKTOP, desktopVersion));
+    assertFalse(clientReleaseManager.isVersionActive(ClientPlatform.DESKTOP, iosVersion));
+    assertFalse(clientReleaseManager.isVersionActive(ClientPlatform.IOS, iosVersion));
+    assertFalse(clientReleaseManager.isVersionActive(ClientPlatform.ANDROID, new Semver("7.8.9")));
+  }
+}