Add tag guard

scm-webapp/src/main/java/sonia/scm/api/v2/resources/TagToTagDtoMapper.java

@@ -16,6 +16,7 @@
 
 package sonia.scm.api.v2.resources;
 
+import com.google.common.annotations.VisibleForTesting;
 import de.otto.edison.hal.Embedded;
 import de.otto.edison.hal.Links;
 import jakarta.inject.Inject;
@@ -27,10 +28,13 @@ import org.mapstruct.ObjectFactory;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.RepositoryPermissions;
 import sonia.scm.repository.Tag;
+import sonia.scm.repository.TagGuard;
+import sonia.scm.repository.TagGuardDeletionRequest;
 import sonia.scm.web.EdisonHalAppender;
 
 import java.time.Instant;
 import java.util.Optional;
+import java.util.Set;
 
 import static de.otto.edison.hal.Embedded.embeddedBuilder;
 import static de.otto.edison.hal.Link.link;
@@ -41,6 +45,8 @@ public abstract class TagToTagDtoMapper extends HalAppenderMapper {
 
   @Inject
   private ResourceLinks resourceLinks;
+  @Inject
+  private Set<TagGuard> tagGuardSet;
 
   @Mapping(target = "date", source = "date", qualifiedByName = "mapDate")
   @Mapping(target = "attributes", ignore = true) // We do not map HAL attributes
@@ -54,7 +60,7 @@ public abstract class TagToTagDtoMapper extends HalAppenderMapper {
       .single(link("sources", resourceLinks.source().self(repository.getNamespace(), repository.getName(), tag.getRevision())))
       .single(link("changeset", resourceLinks.changeset().self(repository.getNamespace(), repository.getName(), tag.getRevision())));
 
-    if (tag.getDeletable() && RepositoryPermissions.push(repository).isPermitted()) {
+    if (tag.getDeletable() && RepositoryPermissions.push(repository).isPermitted() && tagGuardSet.stream().allMatch(guard -> guard.canDelete(new TagGuardDeletionRequest(repository, tag)))) {
       linksBuilder
         .single(link("delete", resourceLinks.tag().delete(repository.getNamespace(), repository.getName(), tag.getName())));
     }
@@ -69,4 +75,14 @@ public abstract class TagToTagDtoMapper extends HalAppenderMapper {
   Instant map(Optional<Long> value) {
     return value.map(Instant::ofEpochMilli).orElse(null);
   }
+
+  @VisibleForTesting
+  void setResourceLinks(ResourceLinks resourceLinks) {
+    this.resourceLinks = resourceLinks;
+  }
+
+  @VisibleForTesting
+  void setTagGuardSet(Set<TagGuard> tagGuardSet) {
+    this.tagGuardSet = tagGuardSet;
+  }
 }

scm-webapp/src/main/java/sonia/scm/repository/TagProtectionException.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2020 - present Cloudogu GmbH
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+package sonia.scm.repository;
+
+import sonia.scm.ExceptionWithContext;
+
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+
+class TagProtectionException extends ExceptionWithContext {
+
+  TagProtectionException(Repository repository, Tag tag, String message) {
+    super(entity(Tag.class, tag.getName()).in(repository).build(), message);
+  }
+
+  @Override
+  public String getCode() {
+    return "99UQi5FKd1";
+  }
+}

scm-webapp/src/main/java/sonia/scm/repository/TagProtectionPreReceiveRepositoryHook.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2020 - present Cloudogu GmbH
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the Free
+ * Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see https://www.gnu.org/licenses/.
+ */
+
+package sonia.scm.repository;
+
+import com.github.legman.Subscribe;
+import com.google.inject.Inject;
+import lombok.extern.slf4j.Slf4j;
+import sonia.scm.EagerSingleton;
+import sonia.scm.plugin.Extension;
+import sonia.scm.repository.api.HookFeature;
+
+import java.util.Set;
+
+@Slf4j
+@Extension
+@EagerSingleton
+public class TagProtectionPreReceiveRepositoryHook {
+
+  private final Set<TagGuard> tagGuards;
+
+  @Inject
+  public TagProtectionPreReceiveRepositoryHook(Set<TagGuard> tagGuards) {
+    this.tagGuards = tagGuards;
+  }
+
+  @Subscribe(async = false)
+  public void onEvent(PreReceiveRepositoryHookEvent event) {
+    if (tagGuards.isEmpty()) {
+      log.trace("no tag guards available, skipping tag protection");
+      return;
+    }
+    Repository repository = event.getRepository();
+    if (repository == null) {
+      log.trace("received hook without repository, skipping tag protection");
+      return;
+    }
+    if (!event.getContext().isFeatureSupported(HookFeature.TAG_PROVIDER)) {
+      log.trace("repository {} does not support tag provider, skipping tag protection", repository);
+      return;
+    }
+
+    event
+      .getContext()
+      .getTagProvider()
+      .getDeletedTags()
+      .forEach(tag -> {
+        boolean tagMustBeProtected = tagGuards.stream().anyMatch(guard -> !guard.canDelete(new TagGuardDeletionRequest(repository, tag)));
+        if (tagMustBeProtected) {
+          String message = String.format("Deleting tag '%s' not allowed in repository %s", tag.getName(), repository);
+          log.info(message);
+
+          if (event.getContext().isFeatureSupported(HookFeature.MESSAGE_PROVIDER)) {
+            event.getContext().getMessageProvider().sendMessage(message);
+          }
+          throw new TagProtectionException(repository, tag, message);
+        } else {
+          log.trace("tag {} does not have to be protected", tag);
+        }
+      });
+  }
+}