Add throttling to /processall endpoint to prevent overwhelming downstream APIs

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/conftest.py

@@ -70,7 +70,8 @@ def client(db_session) -> TestClient:
     
     fastapi_app.dependency_overrides[get_db] = override_get_db
     
-    with TestClient(fastapi_app) as test_client:
+    # Use base_url to satisfy TrustedHostMiddleware
+    with TestClient(fastapi_app, base_url="http://localhost") as test_client:
         yield test_client
     
     # Clean up

tests/test_processall_throttling.py

@@ -0,0 +1,230 @@
+"""
+Tests for /processall endpoint throttling behavior.
+"""
+import os
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+from fastapi.testclient import TestClient
+
+
+@pytest.mark.integration
+class TestProcessAllThrottling:
+    """Tests for processall endpoint with throttling."""
+
+    @patch('app.api.process.process_document')
+    def test_processall_no_throttling_for_small_batch(self, mock_task, client: TestClient, tmp_path, monkeypatch):
+        """Test that small batches (<=20 files) are not throttled."""
+        # Create test directory with 10 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        for i in range(10):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+        
+        # Mock the task
+        mock_task.delay = Mock(return_value=Mock(id="task-id"))
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+        
+        # Use monkeypatch to modify the settings imported in the process module
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+        monkeypatch.setattr(process.settings, 'processall_throttle_threshold', 20)
+        monkeypatch.setattr(process.settings, 'processall_throttle_delay', 3)
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        
+        # Should use .delay() (not throttled)
+        assert mock_task.delay.call_count == 10
+        assert mock_task.apply_async.call_count == 0
+        
+        # Response should indicate no throttling
+        assert data["throttled"] is False
+        assert len(data["pdf_files"]) == 10
+        assert len(data["task_ids"]) == 10
+
+    @patch('app.api.process.process_document')
+    def test_processall_throttling_for_large_batch(self, mock_task, client: TestClient, tmp_path, monkeypatch):
+        """Test that large batches (>20 files) are throttled."""
+        # Create test directory with 25 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        for i in range(25):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+        
+        # Mock the task
+        mock_task_result = Mock(id="task-id")
+        mock_task.apply_async = Mock(return_value=mock_task_result)
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+        monkeypatch.setattr(process.settings, 'processall_throttle_threshold', 20)
+        monkeypatch.setattr(process.settings, 'processall_throttle_delay', 3)
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        
+        # Should use .apply_async() with countdown (throttled)
+        assert mock_task.apply_async.call_count == 25
+        
+        # Verify countdown values are increasing
+        calls = mock_task.apply_async.call_args_list
+        for i, call_args in enumerate(calls):
+            expected_countdown = i * 3  # 3 seconds delay
+            assert call_args[1]['countdown'] == expected_countdown
+        
+        # Response should indicate throttling
+        assert data["throttled"] is True
+        assert len(data["pdf_files"]) == 25
+        assert len(data["task_ids"]) == 25
+        assert "throttled over" in data["message"]
+
+    @patch('app.api.process.process_document')
+    def test_processall_exactly_at_threshold(self, mock_task, client: TestClient, tmp_path, monkeypatch):
+        """Test behavior when file count equals threshold."""
+        # Create test directory with exactly 20 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        for i in range(20):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+        
+        # Mock the task
+        mock_task.delay = Mock(return_value=Mock(id="task-id"))
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+        monkeypatch.setattr(process.settings, 'processall_throttle_threshold', 20)
+        monkeypatch.setattr(process.settings, 'processall_throttle_delay', 3)
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        
+        # At threshold, should NOT throttle (only >threshold)
+        assert mock_task.delay.call_count == 20
+        assert data["throttled"] is False
+
+    @patch('app.api.process.process_document')
+    def test_processall_one_over_threshold(self, mock_task, client: TestClient, tmp_path, monkeypatch):
+        """Test that throttling activates at threshold + 1."""
+        # Create test directory with 21 PDF files (threshold is 20)
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        for i in range(21):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+        
+        # Mock the task
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+        monkeypatch.setattr(process.settings, 'processall_throttle_threshold', 20)
+        monkeypatch.setattr(process.settings, 'processall_throttle_delay', 3)
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        
+        # Should be throttled
+        assert mock_task.apply_async.call_count == 21
+        assert data["throttled"] is True
+
+    def test_processall_empty_directory(self, client: TestClient, tmp_path, monkeypatch):
+        """Test processall with no PDF files."""
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        assert data["message"] == "No PDF files found in that directory."
+
+    def test_processall_nonexistent_directory(self, client: TestClient, tmp_path, monkeypatch):
+        """Test processall with non-existent directory."""
+        workdir = tmp_path / "nonexistent"
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 400
+        data = response.json()
+        assert "does not exist" in data["detail"]
+
+    @patch('app.api.process.process_document')
+    def test_processall_custom_threshold(self, mock_task, client: TestClient, tmp_path, monkeypatch):
+        """Test that custom threshold value is respected."""
+        # Create test directory with 15 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+        
+        for i in range(15):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+        
+        # Mock the task
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+        
+        from app.api import process
+        monkeypatch.setattr(process.settings, 'workdir', str(workdir))
+        monkeypatch.setattr(process.settings, 'processall_throttle_threshold', 10)  # Lower threshold
+        monkeypatch.setattr(process.settings, 'processall_throttle_delay', 2)
+            
+        response = client.post("/api/processall")
+        
+        assert response.status_code == 200
+        data = response.json()
+        
+        # Should be throttled because 15 > 10
+        assert mock_task.apply_async.call_count == 15
+        assert data["throttled"] is True
+
+
+@pytest.mark.unit
+class TestThrottlingConfiguration:
+    """Tests for throttling configuration settings."""
+
+    def test_default_throttle_threshold(self):
+        """Test that default threshold is 20."""
+        from app.config import Settings
+        settings = Settings(
+            database_url="sqlite:///test.db",
+            redis_url="redis://localhost",
+            openai_api_key="test-key",
+            workdir="/tmp",
+            azure_ai_key="test-key",
+            azure_region="test-region",
+            azure_endpoint="https://test.endpoint",
+            gotenberg_url="http://gotenberg",
+            session_secret="a" * 32,
+        )
+        assert settings.processall_throttle_threshold == 20
+
+    def test_default_throttle_delay(self):
+        """Test that default delay is 3 seconds."""
+        from app.config import Settings
+        settings = Settings(
+            database_url="sqlite:///test.db",
+            redis_url="redis://localhost",
+            openai_api_key="test-key",
+            workdir="/tmp",
+            azure_ai_key="test-key",
+            azure_region="test-region",
+            azure_endpoint="https://test.endpoint",
+            gotenberg_url="http://gotenberg",
+            session_secret="a" * 32,
+        )
+        assert settings.processall_throttle_delay == 3