Adds a "private_key" alternative extra field to GitHub connection (#60640)

Author: dym-ok

providers/github/docs/connections/github.rst

@@ -52,6 +52,7 @@ GitHub App authentication
 You can authenticate using a GitHub App installation by setting the extra field of your connection, instead of using a token.
 
 - ``key_path``: Path to the private key file used for GitHub App authentication.
+- ``private_key``: The private key content used for GitHub App authentication. (alternative to ``key_path``)
 - ``app_id``: The application ID.
 - ``installation_id``: The ID of the app installation.
 - ``token_permissions``: A dictionary of permissions. - Properties of permissions - https://docs.github.com/en/rest/apps/apps?apiVersion=2022-11-28#create-an-installation-access-token-for-an-app
@@ -69,3 +70,17 @@ Example "extras" field:
         "contents":"read"
       }
     }
+
+Example with embedded private key:
+
+.. code-block:: json
+
+    {
+      "private_key": "-----BEGIN+PRIVATE+KEY-----%0AM...%0A-----END+PRIVATE+KEY-----",
+      "app_id": "123456s",
+      "installation_id": 123456789,
+      "token_permissions": {
+        "issues":"write",
+        "contents":"read"
+      }
+    }

providers/github/src/airflow/providers/github/hooks/github.py

@@ -64,8 +64,13 @@ def get_conn(self) -> GithubClient:
                     raise ValueError("Unrecognised key file: expected a .pem private key")
                 with open(key_path) as key_file:
                     private_key = key_file.read()
+            elif key := extras.get("private_key"):
+                private_key = key
+
             else:
-                raise ValueError("No key_path provided for GitHub App authentication.")
+                raise ValueError(
+                    "Neither key_path nor private_key are provided for GitHub App authentication."
+                )
 
             app_id = extras.get("app_id")
             installation_id = extras.get("installation_id")

providers/github/tests/unit/github/hooks/test_github.py

@@ -54,6 +54,19 @@ def setup_connections(self, create_connection_without_db):
                 },
             )
         )
+        create_connection_without_db(
+            Connection(
+                conn_id="github_app_embedded_key",
+                conn_type="github",
+                host="https://mygithub.com/api/v3",
+                extra={
+                    "app_id": "123456",
+                    "installation_id": 654321,
+                    "private_key": "-----BEGIN+PRIVATE+KEY-----%0AM...%0A-----END+PRIVATE+KEY-----",
+                    "token_permissions": {"issues": "write", "pull_requests": "read"},
+                },
+            )
+        )
 
     @patch(
         "airflow.providers.github.hooks.github.GithubClient", autospec=True, return_value=github_client_mock
@@ -65,7 +78,7 @@ def test_github_client_connection(self, github_mock):
         assert isinstance(github_hook.client, Mock)
         assert github_hook.client.name == github_mock.return_value.name
 
-    @pytest.mark.parametrize("conn_id", ["github_default", "github_app_conn"])
+    @pytest.mark.parametrize("conn_id", ["github_default", "github_app_conn", "github_app_embedded_key"])
     @patch(
         "airflow.providers.github.hooks.github.open",
         new_callable=mock_open,
@@ -81,7 +94,7 @@ def test_connection_success(self, mock_file, conn_id):
         assert status is True
         assert msg == "Successfully connected to GitHub."
 
-    @pytest.mark.parametrize("conn_id", ["github_default", "github_app_conn"])
+    @pytest.mark.parametrize("conn_id", ["github_default", "github_app_conn", "github_app_embedded_key"])
     @patch(
         "airflow.providers.github.hooks.github.open",
         new_callable=mock_open,
@@ -118,7 +131,7 @@ def test_connection_failure(self, mock_file, conn_id):
             (
                 "missing_key_path",
                 {"app_id": "1", "installation_id": 1},
-                "No key_path provided for GitHub App authentication.",
+                "Neither key_path nor private_key are provided for GitHub App authentication.",
             ),
             # installation_id is not integer
             (