Add context manager and close() to ClientBase (#121)

* Add context manager and close() to ClientBase

Allows using CustomerIO and APIClient as context managers to properly
close the underlying requests Session and avoid ResourceWarning for
unclosed SSL sockets.

Closes #87

Author: hownowstephen

customerio/client_base.py

@@ -24,6 +24,19 @@ def __init__(self, retries=3, timeout=10, backoff_factor=0.02, use_connection_po
         self.use_connection_pooling = use_connection_pooling
         self._current_session = None
 
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        self.close()
+
+    def close(self):
+        if self._current_session is not None:
+            try:
+                self._current_session.close()
+            finally:
+                self._current_session = None
+
     @property
     def http(self):
         if self._current_session is None:

tests/test_client_base.py

@@ -134,6 +134,46 @@ def build_session(resp=response):
             result = client.send_request("POST", "https://example.com", {})
             self.assertEqual(result.status_code, status)
 
+    def test_context_manager_closes_session(self):
+        client = ClientBase(use_connection_pooling=True)
+        session = FakeSession()
+        client._build_session = lambda: session
+
+        with client:
+            client.send_request("POST", "https://example.com", {})
+            self.assertFalse(session.closed)
+
+        self.assertTrue(session.closed)
+        self.assertIsNone(client._current_session)
+
+    def test_close_without_session(self):
+        client = ClientBase()
+        client.close()
+        self.assertIsNone(client._current_session)
+
+    def test_close_resets_session(self):
+        client = ClientBase(use_connection_pooling=True)
+        session = FakeSession()
+        client._build_session = lambda: session
+
+        client.send_request("POST", "https://example.com", {})
+        self.assertIsNotNone(client._current_session)
+
+        client.close()
+        self.assertTrue(session.closed)
+        self.assertIsNone(client._current_session)
+
+    def test_close_resets_session_even_on_error(self):
+        client = ClientBase(use_connection_pooling=True)
+        session = FakeSession()
+        session.close = lambda: (_ for _ in ()).throw(RuntimeError("close failed"))
+        client._current_session = session
+
+        with self.assertRaises(RuntimeError):
+            client.close()
+
+        self.assertIsNone(client._current_session)
+
 
 if __name__ == "__main__":
     unittest.main()