Add explicit close() for session. Add context manager support.

Fixes #278

Author: chauhankaranraj

prometheus_api_client/prometheus_connect.py

@@ -94,6 +94,17 @@ def __init__(
             self._session.proxies = proxy
         self._session.mount(self.url, HTTPAdapter(max_retries=retry))
 
+    def close(self) -> None:
+        """Close the underlying HTTP session and release connection-pool resources."""
+        self._session.close()
+
+    def __enter__(self):
+        """Support usage as a context manager: ``with PrometheusConnect(...) as pc:``"""
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+
     def check_prometheus_connection(self, params: dict = None) -> bool:
         """
         Check Promethus connection.

tests/test_prometheus_connect.py

@@ -395,5 +395,14 @@ def test_get_label_values_method(self):  # noqa D102
             request = handler.requests[0]
             self.assertEqual(request.path_url, "/api/v1/label/label_name/values")
 
+    def test_close(self):  # noqa D102
+        self.pc.close()  # must not raise
+
+    def test_context_manager(self):  # noqa D102
+        with PrometheusConnect(url="http://doesnt_matter.xyz", disable_ssl=True) as pc:
+            self.assertIsInstance(pc, PrometheusConnect)
+        pc.close()  # idempotent — must not raise after __exit__
+
+
 if __name__ == "__main__":
     unittest.main()