src/main/java/at/ac/uibk/gitsearch/config/SecurityConfiguration.java

@@ -11,22 +11,30 @@ import at.ac.uibk.gitsearch.security.oauth2.SavedRequestAwareAuthenticationSucce
 import at.ac.uibk.gitsearch.security.oauth2.UserDetailsFetcher;
 import at.ac.uibk.gitsearch.service.UserService;
 import at.ac.uibk.gitsearch.service.dto.AdminUserDTO;
+import at.ac.uibk.gitsearch.service.dto.OAuth2ConfigDTO;
 import at.ac.uibk.gitsearch.service.mapper.UserMapper;
 import java.net.InetAddress;
 import java.net.URI;
 import java.net.UnknownHostException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import javax.annotation.Nonnull;
+import javax.annotation.PostConstruct;
 import javax.servlet.DispatcherType;
 import javax.servlet.http.HttpServletRequest;
+import javax.ws.rs.ServiceUnavailableException;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientProperties;
+import org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientPropertiesRegistrationAdapter;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Import;
@@ -57,6 +65,8 @@ import org.springframework.security.oauth2.client.endpoint.OAuth2AuthorizationCo
 import org.springframework.security.oauth2.client.oidc.userinfo.OidcUserRequest;
 import org.springframework.security.oauth2.client.oidc.userinfo.OidcUserService;
 import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
+import org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository;
 import org.springframework.security.oauth2.client.userinfo.OAuth2UserService;
 import org.springframework.security.oauth2.client.web.AuthorizationRequestRepository;
 import org.springframework.security.oauth2.client.web.OAuth2LoginAuthenticationFilter;
@@ -83,6 +93,7 @@ import org.springframework.security.web.header.writers.ReferrerPolicyHeaderWrite
 import org.springframework.security.web.util.matcher.AndRequestMatcher;
 import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
 import org.springframework.security.web.util.matcher.RequestMatcher;
+import org.springframework.stereotype.Service;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.web.filter.CorsFilter;
@@ -511,4 +522,61 @@ public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
       return oidcUser;
     };
   }
+
+  /**
+   * overriding, in order to handle failed OAuth2 initializations. We defer the
+   * initialization to later.
+   *
+   * @param properties
+   * @return
+   */
+  @Service(value = "clientRegistrationRepository")
+  public static class DeferredClientRegistrationRepository implements ClientRegistrationRepository {
+
+    private static final Logger logger = LogManager.getLogger(SecurityConfiguration.class);
+
+    @Autowired
+    private OAuth2ClientProperties properties;
+
+    private InMemoryClientRegistrationRepository wrapped;
+
+    @PostConstruct
+    public void init() {
+      List<ClientRegistration> registrations;
+      try {
+        registrations = new ArrayList<>(OAuth2ClientPropertiesRegistrationAdapter.getClientRegistrations(properties).values());
+      } catch (IllegalArgumentException e) {
+        logger.warn("Cannot initialize OAuth Client Infrastructure. Deferring Initializition to first request.", e);
+        return;
+      }
+      wrapped = new InMemoryClientRegistrationRepository(registrations);
+    }
+
+    private void initOrThrow() throws ServiceUnavailableException {
+      List<ClientRegistration> registrations;
+      try {
+        registrations = new ArrayList<>(OAuth2ClientPropertiesRegistrationAdapter.getClientRegistrations(properties).values());
+      } catch (IllegalArgumentException e) {
+        throw new ServiceUnavailableException("OAuth2 Service not yet initialized: " + e.getMessage());
+      }
+      wrapped = new InMemoryClientRegistrationRepository(registrations);
+    }
+
+    @Override
+    public ClientRegistration findByRegistrationId(String registrationId) {
+      initOrThrow();
+      return wrapped.findByRegistrationId(registrationId);
+    }
+
+    public OAuth2ConfigDTO[] getPublicRegistrations() {
+      initOrThrow();
+      final List<OAuth2ConfigDTO> result = new ArrayList<>();
+      wrapped.iterator().forEachRemaining(registration -> result.add(buildConfigFromRegistration(registration)));
+      return result.toArray(new OAuth2ConfigDTO[] {});
+    }
+
+    private OAuth2ConfigDTO buildConfigFromRegistration(ClientRegistration registration) {
+      return new OAuth2ConfigDTO(registration);
+    }
+  }
 }

src/main/java/at/ac/uibk/gitsearch/service/oauth2/OAuth2ConfigService.java

 package at.ac.uibk.gitsearch.service.oauth2;
 
+import at.ac.uibk.gitsearch.config.SecurityConfiguration.DeferredClientRegistrationRepository;
 import at.ac.uibk.gitsearch.service.dto.OAuth2ConfigDTO;
-import java.util.ArrayList;
-import java.util.List;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.security.oauth2.client.registration.ClientRegistration;
-import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
-import org.springframework.security.oauth2.client.registration.InMemoryClientRegistrationRepository;
 import org.springframework.stereotype.Service;
 
 /**
- * provides functions for the retrieval of information on configured OAuth2 services
+ * provides functions for the retrieval of information on configured OAuth2
+ * services
+ *
  * @author Michael Breu
  */
 @Service
@@ -22,31 +21,17 @@ public class OAuth2ConfigService {
 
   @Autowired
   @SuppressWarnings("PMD.ImmutableField")
-  private ClientRegistrationRepository oauth2ClientRegistrationRepositories;
+  private DeferredClientRegistrationRepository oauth2ClientRegistrationRepositories;
 
   public OAuth2ConfigDTO findByRegistrationId(String registrationId) {
     final ClientRegistration registration = oauth2ClientRegistrationRepositories.findByRegistrationId(registrationId);
     if (registration == null) {
       return null;
     }
-    return buildConfigFromRegistration(registration);
+    return new OAuth2ConfigDTO(registration);
   }
 
   public OAuth2ConfigDTO[] getPublicRegistrations() {
-    if (oauth2ClientRegistrationRepositories instanceof InMemoryClientRegistrationRepository) {
-      InMemoryClientRegistrationRepository imOAuth2ClientRegistrationRepositories = (InMemoryClientRegistrationRepository) oauth2ClientRegistrationRepositories;
-      final List<OAuth2ConfigDTO> result = new ArrayList<>();
-      imOAuth2ClientRegistrationRepositories
-        .iterator()
-        .forEachRemaining(registration -> result.add(buildConfigFromRegistration(registration)));
-      return result.toArray(new OAuth2ConfigDTO[] {});
-    } else {
-      log.warn("Cannot find any OAuth2 Registrations");
-      return new OAuth2ConfigDTO[] {};
-    }
-  }
-
-  private OAuth2ConfigDTO buildConfigFromRegistration(ClientRegistration registration) {
-    return new OAuth2ConfigDTO(registration);
+    return oauth2ClientRegistrationRepositories.getPublicRegistrations();
   }
 }

src/main/java/at/ac/uibk/gitsearch/web/rest/OAuth2ConfigResource.java

@@ -2,6 +2,7 @@ package at.ac.uibk.gitsearch.web.rest;
 
 import at.ac.uibk.gitsearch.service.dto.OAuth2ConfigDTO;
 import at.ac.uibk.gitsearch.service.oauth2.OAuth2ConfigService;
+import javax.ws.rs.ServiceUnavailableException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -29,6 +30,10 @@ public class OAuth2ConfigResource {
 
   @GetMapping("/allConfigs")
   public ResponseEntity<OAuth2ConfigDTO[]> getOAuth2Configs() {
-    return new ResponseEntity<>(oAuth2ConfigService.getPublicRegistrations(), HttpStatus.OK);
+    try {
+      return new ResponseEntity<>(oAuth2ConfigService.getPublicRegistrations(), HttpStatus.OK);
+    } catch (ServiceUnavailableException e) {
+      return new ResponseEntity<OAuth2ConfigDTO[]>(HttpStatus.SERVICE_UNAVAILABLE);
+    }
   }
 }