[#12048] Add dangling course delete script

src/client/java/teammates/client/scripts/sql/DeleteDanglingCourseScript.java

@@ -0,0 +1,120 @@
+package teammates.client.scripts.sql;
+
+import java.io.IOException;
+
+import java.util.Optional;
+
+import teammates.client.connector.DatastoreClient;
+import teammates.client.util.ClientProperties;
+import teammates.common.util.HibernateUtil;
+import teammates.storage.entity.Course;
+import teammates.test.FileHelper;
+
+
+import com.google.cloud.datastore.Cursor;
+import com.google.cloud.datastore.QueryResults;
+import com.googlecode.objectify.cmd.Query;
+import com.googlecode.objectify.Objectify;
+import com.googlecode.objectify.ObjectifyService;
+
+
+public class DeleteDanglingCourseScript extends DatastoreClient {
+    private static final String BASE_LOG_URI = "src/client/java/teammates/client/scripts/log/";
+    private static final String COURSE_MIGRATION_SCRIPT_NAME = "DataMigrationForCourseEntitySql";
+    public static void main(String[] args) {
+        String connectionUrl = ClientProperties.SCRIPT_API_URL;
+        String username = ClientProperties.SCRIPT_API_NAME;
+        String password = ClientProperties.SCRIPT_API_PASSWORD;
+
+        HibernateUtil.buildSessionFactory(connectionUrl, username, password);
+
+        DeleteDanglingCourseScript script = new DeleteDanglingCourseScript();
+        script.doOperationRemotely();
+    }
+
+    protected void doOperation() {
+        deleteDanglingCourse();
+    }
+
+
+    private void deleteDanglingCourse() {
+        Cursor cursor = readPositionOfCursorFromFile().orElse(null);
+        if (cursor == null) {
+            throw new Error("No cursor found!");
+        }
+
+        Course danglingCourse = getDanglingCourse(cursor);
+        log("Deleting partially migrated course: " + danglingCourse.getUniqueId());
+        deleteCourseCascade(danglingCourse);
+    }
+
+    private Course getDanglingCourse(Cursor cursor) {
+        Query<Course> filterQueryKeys = getFilterQuery().limit(1);
+        filterQueryKeys = filterQueryKeys.startAt(cursor);
+        QueryResults<?> iterator = filterQueryKeys.iterator();
+
+        Course course = null;
+        // Cascade delete the course if it is not fully migrated.
+        if (iterator.hasNext()) {
+            course = (Course) iterator.next();
+            if (course.isMigrated()) {
+                throw new Error("Course does not have any dangling entities");
+            }
+            Course danglingCourse = course;
+            return danglingCourse;
+        } else {
+            throw new Error("No course remaining");
+        }
+    }
+
+    protected Objectify ofy() {
+        return ObjectifyService.ofy();
+    }
+
+    protected Query<Course> getFilterQuery() {
+        return ofy().load().type(Course.class);
+    }
+
+    /**
+     * Deletes the course and its related entities from sql database.
+     */
+    private void deleteCourseCascade(Course oldCourse) {
+        String courseId = oldCourse.getUniqueId();
+
+        HibernateUtil.beginTransaction();
+        teammates.storage.sqlentity.Course newCourse = HibernateUtil.get(teammates.storage.sqlentity.Course.class, courseId);
+        if (newCourse == null) {
+            HibernateUtil.commitTransaction();
+            throw new Error("Course does not have any dangling entities");
+        }
+
+        log("delete dangling course with id: " + courseId);
+        HibernateUtil.remove(newCourse);
+        HibernateUtil.flushSession();
+        HibernateUtil.clearSession();
+        HibernateUtil.commitTransaction();
+    }
+
+    /**
+     * Reads the cursor position from the saved file.
+     *
+     * @return cursor if the file can be properly decoded.
+     */
+    private Optional<Cursor> readPositionOfCursorFromFile() {
+        try {
+            String cursorPosition =
+                    FileHelper.readFile(BASE_LOG_URI + COURSE_MIGRATION_SCRIPT_NAME + ".cursor");
+            return Optional.of(Cursor.fromUrlSafe(cursorPosition));
+        } catch (IOException | IllegalArgumentException e) {
+            return Optional.empty();
+        }
+    }
+
+    protected void log(String logLine) {
+        System.out.println(String.format("%s %s", getLogPrefix(), logLine));
+    }
+
+    protected String getLogPrefix() {
+        return String.format("Cleaning up dangling course: ");
+    }
+}

src/client/java/teammates/client/scripts/sql/SeedDb.java

@@ -446,8 +446,7 @@ private void seedAccountRequests() {
                 AccountRequest accountRequest = AccountRequestAttributes
                         .builder(accountRequestEmail, accountRequestInstitute, accountRequestName)
                         .withRegisteredAt(Instant.now()).build().toEntity();
-
-                ofy().save().entities(accountRequest).now();
+                saveEntityDeferred(buffer, accountRequest);
             } catch (Exception e) {
                 log("Account and account request" + e.toString());
             }
@@ -496,7 +495,6 @@ public static void main(String[] args) throws Exception {
     @Override
     protected void doOperation() {
         try {
-            // clearDataStore();
             // LogicStarter.initializeDependencies();
             this.persistData();
         } catch (Exception e) {