RHEL-9435: Get AWS metadata via IMDSv2

* Card ID: RHEL-9435

Even though both versions are officially supported, the AWS teams are
tracking connections making v1 requests as WARNINGs [0].

This patch switches the order to try to use IMDSv2 first.

[0]: https://github.com/aws/aws-imds-packet-analyzer

src/cloud_what/providers/aws.py

@@ -281,25 +281,20 @@ def _get_metadata_from_server_imds_v2(self) -> Union[str, None]:
 
     def _get_metadata_from_server(self) -> Union[str, None]:
         """
-        Try to get metadata from server as is described in this document:
+        Try to get metadata from server as described in these documents:
+        - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configuring-instance-metadata-service.html
+        - https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-metadata-v2-how-it-works.html
 
-        https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configuring-instance-metadata-service.html
+        IMDSv2 requires two HTTP requests (first requests a token, second obtains the metadata).
+        If that fails, try to fall back to IDMSv1 (which is older and can be disabled in the AWS console).
 
-        It is possible to use two versions. We will try to use version IMDSv1 first (this version requires
-        only one HTTP request), when the usage of IMDSv1 is forbidden, then we will try to use IMDSv2 version.
-        The version requires two requests (get session TOKEN and then get own metadata using token)
         :return: String with metadata or None
         """
+        metadata = self._get_metadata_from_server_imds_v2()
+        if metadata is not None:
+            return metadata
 
-        if self._token_exists() is False:
-            # First try to get metadata using IMDSv1
-            metadata = self._get_metadata_from_server_imds_v1()
-
-            if metadata is not None:
-                return metadata
-
-        # When it wasn't possible to get metadata using IMDSv1, then try to get metadata using IMDSv2
-        return self._get_metadata_from_server_imds_v2()
+        return self._get_metadata_from_server_imds_v1()
 
     def _get_signature_from_cache_file(self) -> None:
         """

test/test_auto_registration.py

@@ -18,7 +18,7 @@
 
 import unittest
 import base64
-from unittest.mock import patch, Mock
+from unittest.mock import Mock
 
 from subscription_manager.scripts.rhsmcertd_worker import _collect_cloud_info
 from .rhsmlib.facts.test_cloud_facts import AWS_METADATA
@@ -93,11 +93,17 @@ def send_only_imds_v2_is_supported(request, *args, **kwargs):
     return mock_result
 
 
-def mock_prepare_request(request):
-    return request
+class TestAutomaticRegistration(unittest.TestCase):
+    def setUp(self):
+        _ = aws.AWSCloudProvider({})
+        aws.AWSCloudProvider._instance._get_metadata_from_cache = Mock(return_value=None)
+        aws.AWSCloudProvider._instance._get_token_from_cache_file = Mock(return_value=None)
+        aws.AWSCloudProvider._instance._write_token_to_cache_file = Mock()
 
+        _ = azure.AzureCloudProvider({})
+        azure.AzureCloudProvider._instance._get_metadata_from_cache = Mock(return_value=None)
+        azure.AzureCloudProvider._instance.get_api_versions = Mock(return_value="")
 
-class TestAutomaticRegistration(unittest.TestCase):
     def tearDown(self):
         aws.AWSCloudProvider._instance = None
         aws.AWSCloudProvider._initialized = False
@@ -106,17 +112,16 @@ def tearDown(self):
         gcp.GCPCloudProvider._instance = None
         gcp.GCPCloudProvider._initialized = False
 
-    @patch("cloud_what.providers.aws.requests.Session")
-    def test_collect_cloud_info_one_cloud_provider_detected(self, mock_session_class):
+    def test_collect_cloud_info_one_cloud_provider_detected(self):
         """
         Test the case, when we try to collect cloud info only for
         one detected cloud provider
         """
         mock_session = Mock()
-        mock_session.send = send_only_imds_v2_is_supported
-        mock_session.prepare_request = Mock(side_effect=mock_prepare_request)
+        mock_session.send = send_only_imds_v2_is_supported()
+        mock_session.prepare_request = Mock(side_effect=lambda request: request)
         mock_session.hooks = {"response": []}
-        mock_session_class.return_value = mock_session
+        aws.AWSCloudProvider._instance._session = mock_session
 
         cloud_list = ["aws"]
         cloud_info = _collect_cloud_info(cloud_list, Mock())
@@ -136,18 +141,18 @@ def test_collect_cloud_info_one_cloud_provider_detected(self, mock_session_class
         signature = base64.b64decode(b64_signature).decode("utf-8")
         self.assertEqual(signature, "-----BEGIN PKCS7-----\n" + AWS_SIGNATURE + "\n-----END PKCS7-----")
 
-    @patch("cloud_what.providers.aws.requests.Session")
-    def test_collect_cloud_info_more_cloud_providers_detected(self, mock_session_class):
+    def test_collect_cloud_info_more_cloud_providers_detected(self):
         """
         Test the case, when we try to collect cloud info only for
         more than one cloud providers, because more than one cloud
         providers were detected
         """
         mock_session = Mock()
-        mock_session.send = send_only_imds_v2_is_supported
-        mock_session.prepare_request = Mock(side_effect=mock_prepare_request)
+        mock_session.send = send_only_imds_v2_is_supported()
+        mock_session.prepare_request = Mock(side_effect=lambda request: request)
         mock_session.hooks = {"response": []}
-        mock_session_class.return_value = mock_session
+        aws.AWSCloudProvider._instance._session = mock_session
+        azure.AzureCloudProvider._instance._session = Mock()
 
         # More cloud providers detected
         cloud_list = ["azure", "aws"]