Respect no_proxy environment variable

CHANGES.rst

@@ -7,6 +7,11 @@ Changes in Apache Libcloud 3.9.2
 Common
 ~~~~~~
 
+- Respect the ``no_proxy`` / ``NO_PROXY`` environment variable so an explicitly
+  configured proxy is bypassed for matching hosts.
+  (GITHUB-2077)
+  [Sanjay Santhanam - @Sanjays2402]
+
 - Move tests to python 3.12.
   (#2152)
   [Miguel Caballer - @micafer]

libcloud/http.py

@@ -22,6 +22,7 @@
 
 import requests
 from requests.adapters import HTTPAdapter
+from requests.utils import should_bypass_proxies
 
 import libcloud.security
 from libcloud.utils.py3 import urlparse
@@ -112,6 +113,28 @@ def set_http_proxy(self, proxy_url):
             "https": proxy_url,
         }
 
+
+    def _proxies_for_url(self, url):
+        """
+        Return the proxy mapping to use for ``url``.
+
+        An explicitly configured proxy is skipped when the target host matches
+        the ``no_proxy`` / ``NO_PROXY`` environment variable, so libcloud
+        behaves consistently with other HTTP clients.
+
+        :param url: Absolute request URL.
+        :type url: ``str``
+
+        :rtype: ``dict`` or ``None``
+        """
+        if not self.session.proxies:
+            return None
+
+        if should_bypass_proxies(url, no_proxy=None):
+            return {}
+
+        return None
+
     def _parse_proxy_url(self, proxy_url):
         """
         Parse and validate a proxy URL.
@@ -231,6 +254,7 @@ def request(self, method, url, body=None, headers=None, raw=False, stream=False,
             verify=self.verification,
             timeout=self.session.timeout,
             hooks=hooks,
+            proxies=self._proxies_for_url(url),
         )
 
     def prepared_request(self, method, url, body=None, headers=None, raw=False, stream=False):

libcloud/test/test_connection.py

@@ -161,6 +161,18 @@ def test_constructor(self):
             {"http": "https://127.0.0.6:3129", "https": "https://127.0.0.6:3129"},
         )
 
+    def test_proxy_is_bypassed_for_no_proxy_hosts(self):
+        # Regression test for GITHUB-2077: an explicitly configured proxy must
+        # not be used for hosts listed in the no_proxy environment variable.
+        os.environ["no_proxy"] = "internal.example.com"
+        self.addCleanup(os.environ.pop, "no_proxy", None)
+
+        conn = LibcloudConnection(host="internal.example.com", port=443)
+        conn.set_http_proxy("http://proxy.example.com:3128")
+
+        self.assertEqual(conn._proxies_for_url("https://internal.example.com/path"), {})
+        self.assertIsNone(conn._proxies_for_url("https://other.example.com/path"))
+
     def test_proxy_environment_variables_respected(self):
         """
         Test that proxy environment variables are respected by the underlying Requests library