feat(rerankers): Add new backend, support jina rerankers API (#2121)

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/python/rerankers/test_reranker.py

@@ -0,0 +1,90 @@
+"""
+A test script to test the gRPC service
+"""
+import unittest
+import subprocess
+import time
+import backend_pb2
+import backend_pb2_grpc
+
+import grpc
+
+
+class TestBackendServicer(unittest.TestCase):
+    """
+    TestBackendServicer is the class that tests the gRPC service
+    """
+    def setUp(self):
+        """
+        This method sets up the gRPC service by starting the server
+        """
+        self.service = subprocess.Popen(["python3", "reranker.py", "--addr", "localhost:50051"])
+        time.sleep(10)
+
+    def tearDown(self) -> None:
+        """
+        This method tears down the gRPC service by terminating the server
+        """
+        self.service.kill()
+        self.service.wait()
+
+    def test_server_startup(self):
+        """
+        This method tests if the server starts up successfully
+        """
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                response = stub.Health(backend_pb2.HealthMessage())
+                self.assertEqual(response.message, b'OK')
+        except Exception as err:
+            print(err)
+            self.fail("Server failed to start")
+        finally:
+            self.tearDown()
+
+    def test_load_model(self):
+        """
+        This method tests if the model is loaded successfully
+        """
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                response = stub.LoadModel(backend_pb2.ModelOptions(Model="cross-encoder"))
+                self.assertTrue(response.success)
+                self.assertEqual(response.message, "Model loaded successfully")
+        except Exception as err:
+            print(err)
+            self.fail("LoadModel service failed")
+        finally:
+            self.tearDown()
+
+    def test_rerank(self):
+        """
+        This method tests if the embeddings are generated successfully
+        """
+        try:
+            self.setUp()
+            with grpc.insecure_channel("localhost:50051") as channel:
+                stub = backend_pb2_grpc.BackendStub(channel)
+                request = backend_pb2.RerankRequest(
+                    query="I love you",
+                    documents=["I hate you", "I really like you"],
+                    top_n=2
+                )
+                response = stub.LoadModel(backend_pb2.ModelOptions(Model="cross-encoder"))
+                self.assertTrue(response.success)
+               
+                rerank_response = stub.Rerank(request)
+                print(rerank_response.results[0])
+                self.assertIsNotNone(rerank_response.results)
+                self.assertEqual(len(rerank_response.results), 2)
+                self.assertEqual(rerank_response.results[0].text, "I really like you")
+                self.assertEqual(rerank_response.results[1].text, "I hate you")
+        except Exception as err:
+            print(err)
+            self.fail("Reranker service failed")
+        finally:
+            self.tearDown()