dicoding-dev · achmadardanip · Mar 1, 2025 · Mar 1, 2025 · Mar 1, 2025
diff --git a/README.md b/README.md
@@ -0,0 +1,177 @@
+# Technical Exercise Product Engineer - Enrollment Management System
+
+This Laravel-based application manages enrollments, exams, and submissions. The API exposed to external clients currently consists of only one endpoint: `/api/user`. This README provides step-by-step setup instructions, API documentation for the available endpoint, guidance on running tests, including how to test the `DropOutEnrollments` command, and product analysis document as part of Dicoding Technical Exercise for Product Engineer.
+
+## Table of Contents
+
+- [Setup Instructions](#setup-instructions)
+- [API Documentation](#api-documentation)
+- [Testing Instructions](#testing-instructions)
+  - [Testing the API Using Postman](#testing-the-api-using-postman)
+  - [Testing the DropOutEnrollments Command](#testing-the-dropoutenrollments-command)
+- [Product Analysis Document](#product-analysis-document)
+
+## Setup Instructions
+
+### Prerequisites
+
+- PHP \>= 8.1
+- Composer
+- MySQL or MariaDB database
+
+### Installation
+
+1. **Clone the repository:**
+
+   ```bash
+   git clone https://github.com/achmadardanip/technical-excercise
+   cd technical-excercise
+   ```
+
+2. **Install PHP dependencies using Composer:**
+
+   ```bash
+   composer install
+   ```
+
+3. **Run Migrations and Seed The Database:**
+
+   ```bash
+   php artisan migrate --seed
+   ```
+
+4. **Run The Application**
+
+   ```bash
+   php artisan serve
+   ```
+
+   The application will be accessible at <http://localhost:8000>.
+
+## API Documentation
+
+Since the current API consists of a single endpoint
+
+<img width="536" alt="api list" src="https://github.com/user-attachments/assets/848327cf-b7a9-45c6-9c63-89790030d598" />
+
+Here is the documentation for /api/user:
+
+### GET /api/user
+
+* **Description:**
+  Returns the details of the authenticated user. This endpoint is used in applications where user authentication is required, providing basic information about the logged-in user.
+
+* **Authentication:**
+  This endpoint requires an authenticated request (for example, using Laravel Sanctum or Passport). Ensure you include the necessary authentication headers (e.g., Bearer token).
+
+* **Response Example**
+
+  ```
+  {
+      "id": 1166041,
+      "name": "Monalisa",
+      "email": "[email protected]",
+      "email_verified_at": "2025-03-01T14:58:25.000000Z",
+      "created_at": "2025-03-01T14:58:25.000000Z",
+      "updated_at": "2025-03-01T14:58:25.000000Z"
+  }
+  ```
+
+* **Example Request**
+
+  ```
+  curl -X GET http://localhost:8000/api/user \
+       -H "Authorization: Bearer YOUR_ACCESS_TOKEN"
+  ```
+
+## Testing Instructions
+
+### Testing the API Using Postman
+
+To test the `/api/user` endpoint using Postman, first create a new user using Tinker and generate an API token.
+
+* **Create a New User with Tinker:**
+
+  Open your terminal and start Tinker:
+
+  ```
+  php artisan tinker 
+  ```
+
+  Create a new user (this example uses a factory; adjust if needed):
+
+  ```
+  $user = App\Models\User::factory()->create([
+      'name' => 'Monalisa',
+      'email' => '[email protected]',
+      'password' => bcrypt('secret'),
+  ])
+  ```
+
+* **Generate an API Token (if using Laravel Sanctum or Passport):**
+
+  For example, using Laravel Sanctum:
+
+  ```
+  $token = $user->createToken('Test Token')->plainTextToken;
+  echo $token;
+  ```
+
+* **Run The Application**
+
+  Make sure you start the application again after creating a new user, type the following command:
+
+   ```bash
+   php artisan serve
+   ```
+
+* **Set Up Postman:**
+
+  * Open Postman and create a new GET request to:
+
+    ```
+    http://localhost:8000/api/user
+    ```
+
+  * In the request headers, add token you've got from previous step:
+
+    ```
+    Authorization: Bearer YOUR_GENERATED_TOKEN 
+    ```
+
+  * Click "Send" to make the request.
+
+* **Verify the Response:**
+
+  You should receive a JSON response like the following with the user’s details (matching the newly created user).
+
+  ```
+  {
+      "id": 1166041,
+      "name": "Monalisa",
+      "email": "[email protected]",
+      "email_verified_at": "2025-03-01T14:58:25.000000Z",
+      "created_at": "2025-03-01T14:58:25.000000Z",
+      "updated_at": "2025-03-01T14:58:25.000000Z"
+  }
+  ```
+
+### Testing the DropOutEnrollments Command
+
+- **Run The Command Manually**
+
+  In root directory of the app, run the following command:
+
+  ```
+  php artisan enrollments:dropout
+  ```
+
+  The command will output details such as the number of enrollments processed, excluded, and dropped out, along with performance metrics.
+
+- **Link to Pull Request (testing result and optimization steps)**
+
+  <https://github.com/dicoding-dev/technical-excercise/pull/1>
+
+## Product Analysis Document
+
+[**Click here**](https://docs.google.com/document/d/13JoCo44M9q_hEBQnW6R58gwABcYdL05v7JRO0tw0Uh4/edit?usp=sharing)
diff --git a/app/Console/Commands/DropOutEnrollments.php b/app/Console/Commands/DropOutEnrollments.php
@@ -41,15 +41,19 @@ public function handle()
         try {
             DB::beginTransaction();
 
+            // Retrieve the latest deadline (adjust as needed)
             $deadline = Carbon::parse(Enrollment::latest('id')->value('deadline_at'));
 
             $this->stopwatch->start(__CLASS__);
 
+            // Call the optimized dropout process.
             $this->dropOutEnrollmentsBefore($deadline);
 
-            $this->stopwatch->stop(__CLASS__);
+            $event = $this->stopwatch->stop(__CLASS__);
+
             $this->info($this->stopwatch->getEvent(__CLASS__));
 
+            // Note: Rollback is used here for testing/dry-run purposes.
             DB::rollBack();
         } catch (\Exception $e) {
             DB::rollBack();
@@ -58,50 +62,110 @@ public function handle()
     }
 
     /**
-     * The dropout process should fulfil the following requirements:
-     * 1. The enrollment deadline has passed.
-     * 2. The student has no active exam.
-     * 3. The student has no submission waiting for review.
-     * 4. Update the enrollment status to `DROPOUT`.
-     * 5. Create an activity log for the student.
+     *Optimized dropout process.
+     *
+     * Optimization Documentation:
+     *
+     * - **Step 1: Select Only Required Columns**
+     *   - *What:* Instead of retrieving full model data, we select only 'id', 'course_id', and 'student_id'.
+     *   - *Why:* Reduces memory usage.
+     *   - *How:* Use ->select('id', 'course_id', 'student_id').
+     *
+     * - **Step 2: Bulk Fetch Related Records with Composite Keys**
+     *   - *What:* Use selectRaw to retrieve composite keys (course_id-student_id) for Exams and Submissions.
+     *   - *Why:* Minimizes the data loaded from the database.
+     *   - *How:* Use ->selectRaw("CONCAT(course_id, '-', student_id) as composite_key")->distinct()->pluck('composite_key').
+     *
+     * - **Step 3: Cache Timestamp per Chunk**
+     *   - *What:* Call now() only once per chunk.
+     *   - *Why:* Reduces function call overhead.
+     *   - *How:* Store the result in a $now variable.
+     *
+     * - **Step 4: Use Chunking, and Bulk Update & Insert**
+     *   - *What:* Process enrollments in chunks, then update and insert in bulk.
+     *   - *Why:* Prevents high memory usage and reduces database roundtrips.
+     *   - *How:* Use chunkById(1000) with DB::table()->whereIn()->update() and DB::table()->insert().
+     *
+     * @param Carbon $deadline
      */
     private function dropOutEnrollmentsBefore(Carbon $deadline)
     {
-        $enrollmentsToBeDroppedOut = Enrollment::where('deadline_at', '<=', $deadline)->get();
-
-        $this->info('Enrollments to be dropped out: ' . count($enrollmentsToBeDroppedOut));
-        $droppedOutEnrollments = 0;
-
-        foreach ($enrollmentsToBeDroppedOut as $enrollment) {
-            $hasActiveExam = Exam::where('course_id', $enrollment->course_id)
-                ->where('student_id', $enrollment->student_id)
-                ->where('status', 'IN_PROGRESS')
-                ->exists();
-
-            $hasWaitingReviewSubmission = Submission::where('course_id', $enrollment->course_id)
-                ->where('student_id', $enrollment->student_id)
-                ->where('status', 'WAITING_REVIEW')
-                ->exists();
-
-            if ($hasActiveExam || $hasWaitingReviewSubmission) {
-                continue;
-            }
-
-            $enrollment->update([
-                'status' => 'DROPOUT',
-                'updated_at' => now(),
-            ]);
-
-            Activity::create([
-                'resource_id' => $enrollment->id,
-                'user_id' => $enrollment->student_id,
-                'description' => 'COURSE_DROPOUT',
-            ]);
-
-            $droppedOutEnrollments++;
-        }
-
-        $this->info('Excluded from drop out: ' . count($enrollmentsToBeDroppedOut) - $droppedOutEnrollments);
-        $this->info('Final dropped out enrollments: ' . $droppedOutEnrollments);
+        $this->info('Starting dropout process...');
+        $totalDropped = 0;
+        $totalChecked = 0;
+
+        // Process enrollments in chunks (only select needed columns)
+        Enrollment::select('id', 'course_id', 'student_id')
+            ->where('deadline_at', '<=', $deadline)
+            ->chunkById(1000, function ($enrollments) use (&$totalDropped, &$totalChecked) {
+                // Extract unique course_ids and student_ids from the current chunk.
+                $courseIds = $enrollments->pluck('course_id')->unique()->toArray();
+                $studentIds = $enrollments->pluck('student_id')->unique()->toArray();
+
+                // Build lookup for active exams using composite keys.
+                $activeExamKeys = Exam::selectRaw("CONCAT(course_id, '-', student_id) as composite_key")
+                    ->whereIn('course_id', $courseIds)
+                    ->whereIn('student_id', $studentIds)
+                    ->where('status', 'IN_PROGRESS')
+                    ->distinct()
+                    ->pluck('composite_key')
+                    ->toArray();
+                $activeExamLookup = array_flip($activeExamKeys);
+
+                // Build lookup for waiting submissions using composite keys.
+                $waitingSubmissionKeys = Submission::selectRaw("CONCAT(course_id, '-', student_id) as composite_key")
+                    ->whereIn('course_id', $courseIds)
+                    ->whereIn('student_id', $studentIds)
+                    ->where('status', 'WAITING_REVIEW')
+                    ->distinct()
+                    ->pluck('composite_key')
+                    ->toArray();
+                $waitingSubmissionLookup = array_flip($waitingSubmissionKeys);
+
+                // Prepare arrays for bulk update and bulk insert.
+                $enrollmentIdsToDrop = [];
+                $activityLogs = [];
+                $now = now(); // Cache current timestamp for the entire chunk
+
+                foreach ($enrollments as $enrollment) {
+                    $totalChecked++;
+                    $key = $enrollment->course_id . '-' . $enrollment->student_id;
+
+                    // Skip enrollment if it has an active exam or waiting submission.
+                    if (isset($activeExamLookup[$key]) || isset($waitingSubmissionLookup[$key])) {
+                        continue;
+                    }
+
+                    $enrollmentIdsToDrop[] = $enrollment->id;
+                    $activityLogs[] = [
+                        'resource_id' => $enrollment->id,
+                        'user_id'     => $enrollment->student_id,
+                        'description' => 'COURSE_DROPOUT',
+                        'created_at'  => $now,
+                        'updated_at'  => $now,
+                    ];
+                    $totalDropped++;
+                }
+
+                // Bulk update enrollments that qualify for dropout.
+                if (!empty($enrollmentIdsToDrop)) {
+                    DB::table('enrollments')
+                        ->whereIn('id', $enrollmentIdsToDrop)
+                        ->update([
+                            'status'     => 'DROPOUT',
+                            'updated_at' => $now,
+                        ]);
+                }
+
+                // Bulk insert all the activity log records.
+                if (!empty($activityLogs)) {
+                    DB::table('activities')->insert($activityLogs);
+                }
+            });
+
+        // Output process statistics.
+        $this->info("Enrollments to be dropped out: $totalChecked");
+        $this->info("Excluded from drop out: " . ($totalChecked - $totalDropped));
+        $this->info("Final dropped out enrollments: $totalDropped");
     }
 }