Lazily get captcha clients to avoid initialization issues

service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java

@@ -57,6 +57,7 @@
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.ThreadPoolExecutor;
+import java.util.function.Function;
 import java.util.stream.Stream;
 import javax.annotation.Nullable;
 import javax.servlet.DispatcherType;
@@ -1057,19 +1058,19 @@ protected void configureServer(final ServerBuilder<?> serverBuilder) {
           log.warn("No registration-recovery-checkers found; using default (no-op) provider as a default");
           return RegistrationRecoveryChecker.noop();
         });
-    final List<CaptchaClient> captchaClients = spamFilter
-        .map(SpamFilter::getCaptchaClients)
+    final Function<String, CaptchaClient> captchaClientSupplier = spamFilter
+        .map(SpamFilter::getCaptchaClientSupplier)
         .orElseGet(() -> {
           log.warn("No captcha clients found; using default (no-op) client as default");
-          return List.of(CaptchaClient.noop());
+          return ignored -> CaptchaClient.noop();
         });
 
     spamFilter.map(SpamFilter::getReportedMessageListener).ifPresent(reportMessageManager::addListener);
 
     final HttpClient shortCodeRetrieverHttpClient = HttpClient.newBuilder().version(HttpClient.Version.HTTP_2)
         .connectTimeout(Duration.ofSeconds(10)).build();
     final ShortCodeExpander shortCodeRetriever = new ShortCodeExpander(shortCodeRetrieverHttpClient, config.getShortCodeRetrieverConfiguration().baseUrl());
-    final CaptchaChecker captchaChecker = new CaptchaChecker(shortCodeRetriever, captchaClients);
+    final CaptchaChecker captchaChecker = new CaptchaChecker(shortCodeRetriever, captchaClientSupplier);
 
     final RegistrationCaptchaManager registrationCaptchaManager = new RegistrationCaptchaManager(captchaChecker);
 

service/src/main/java/org/whispersystems/textsecuregcm/captcha/CaptchaChecker.java

@@ -10,12 +10,9 @@
 import com.google.common.annotations.VisibleForTesting;
 import io.micrometer.core.instrument.Metrics;
 import java.io.IOException;
-import java.util.List;
 import java.util.Locale;
-import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
-import java.util.stream.Collectors;
 import javax.ws.rs.BadRequestException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -32,14 +29,13 @@ public class CaptchaChecker {
   private static final String SHORT_SUFFIX = "-short";
 
   private final ShortCodeExpander shortCodeExpander;
-  private final Map<String, CaptchaClient> captchaClientMap;
+  private final Function<String, CaptchaClient> captchaClientSupplier;
 
   public CaptchaChecker(
       final ShortCodeExpander shortCodeRetriever,
-      final List<CaptchaClient> captchaClients) {
+      final Function<String, CaptchaClient> captchaClientSupplier) {
     this.shortCodeExpander = shortCodeRetriever;
-    this.captchaClientMap = captchaClients.stream()
-        .collect(Collectors.toMap(CaptchaClient::scheme, Function.identity()));
+    this.captchaClientSupplier = captchaClientSupplier;
   }
 
 
@@ -81,7 +77,7 @@ public AssessmentResult verify(
       token = shortCodeExpander.retrieve(token).orElseThrow(() -> new BadRequestException("invalid shortcode"));
     }
 
-    final CaptchaClient client = this.captchaClientMap.get(provider);
+    final CaptchaClient client = this.captchaClientSupplier.apply(provider);
     if (client == null) {
       throw new BadRequestException("invalid captcha scheme");
     }

service/src/main/java/org/whispersystems/textsecuregcm/spam/SpamFilter.java

@@ -9,6 +9,7 @@
 import io.dropwizard.lifecycle.Managed;
 import java.io.IOException;
 import java.util.List;
+import java.util.function.Function;
 import javax.validation.Validator;
 import org.whispersystems.textsecuregcm.captcha.CaptchaChecker;
 import org.whispersystems.textsecuregcm.captcha.CaptchaClient;
@@ -84,5 +85,12 @@ public interface SpamFilter extends Managed {
    */
   RegistrationRecoveryChecker getRegistrationRecoveryChecker();
 
-  List<CaptchaClient> getCaptchaClients();
+  /**
+   * Return a function that will be used to lazily fetch the captcha client for a specified scheme. This is to avoid
+   * initialization issues with the spam filter if eagerly fetched.
+   *
+   * @return a {@link Function} that takes the scheme and returns a {@link CaptchaClient}. Returns null if no captcha
+   * client for the scheme exists
+   */
+  Function<String, CaptchaClient> getCaptchaClientSupplier();
 }

service/src/test/java/org/whispersystems/textsecuregcm/captcha/CaptchaCheckerTest.java

@@ -18,6 +18,7 @@
 import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Stream;
 import javax.ws.rs.BadRequestException;
@@ -79,7 +80,7 @@ void parseInputToken(
       final String siteKey,
       final Action expectedAction) throws IOException {
     final CaptchaClient captchaClient = mockClient(PREFIX);
-    new CaptchaChecker(null, List.of(captchaClient)).verify(expectedAction, input, null, USER_AGENT);
+    new CaptchaChecker(null, PREFIX -> captchaClient).verify(expectedAction, input, null, USER_AGENT);
     verify(captchaClient, times(1)).verify(eq(siteKey), eq(expectedAction), eq(expectedToken), any(), eq(USER_AGENT));
   }
 
@@ -106,11 +107,12 @@ public void choose() throws IOException {
     String binput = String.join(SEPARATOR, PREFIX_B, CHALLENGE_SITE_KEY, "challenge", TOKEN);
     final CaptchaClient a = mockClient(PREFIX_A);
     final CaptchaClient b = mockClient(PREFIX_B);
+    final Map<String, CaptchaClient> captchaClientMap = Map.of(PREFIX_A, a, PREFIX_B, b);
 
-    new CaptchaChecker(null, List.of(a, b)).verify(Action.CHALLENGE, ainput, null, USER_AGENT);
+    new CaptchaChecker(null, captchaClientMap::get).verify(Action.CHALLENGE, ainput, null, USER_AGENT);
     verify(a, times(1)).verify(any(), any(), any(), any(), any());
 
-    new CaptchaChecker(null, List.of(a, b)).verify(Action.CHALLENGE, binput, null, USER_AGENT);
+    new CaptchaChecker(null, captchaClientMap::get).verify(Action.CHALLENGE, binput, null, USER_AGENT);
     verify(b, times(1)).verify(any(), any(), any(), any(), any());
   }
 
@@ -132,7 +134,7 @@ static Stream<Arguments> badArgs() {
   public void badArgs(final String input) throws IOException {
     final CaptchaClient cc = mockClient(PREFIX);
     assertThrows(BadRequestException.class,
-        () -> new CaptchaChecker(null, List.of(cc)).verify(Action.CHALLENGE, input, null, USER_AGENT));
+        () -> new CaptchaChecker(null, prefix -> PREFIX.equals(prefix) ? cc : null).verify(Action.CHALLENGE, input, null, USER_AGENT));
 
   }
 
@@ -142,7 +144,7 @@ public void testShortened() throws IOException {
     final ShortCodeExpander retriever = mock(ShortCodeExpander.class);
     when(retriever.retrieve("abc")).thenReturn(Optional.of(TOKEN));
     final String input = String.join(SEPARATOR, PREFIX + "-short", REG_SITE_KEY, "registration", "abc");
-    new CaptchaChecker(retriever, List.of(captchaClient)).verify(Action.REGISTRATION, input, null, USER_AGENT);
+    new CaptchaChecker(retriever, ignored -> captchaClient).verify(Action.REGISTRATION, input, null, USER_AGENT);
     verify(captchaClient, times(1)).verify(eq(REG_SITE_KEY), eq(Action.REGISTRATION), eq(TOKEN), any(), any());
 
   }