Improve EOF error messaging during CLI login flows

Motivated by observed issues in Compute - users can set up working
Compute endpoints, change their setups slightly around access to STDIN,
and then see cryptic EOF errors when they eventually need to re-auth.

NB: as of the time of this commit, Compute handles this by raising an
error before running login flows if the current environment does not
appear to be an interactive terminal. The goal of this commit is to move
that behavior to a more centralized location.

changelog.d/20241024_113828_chris_command_line_login_flow_manager_catch_eof.rst

@@ -0,0 +1,5 @@
+Changed
+~~~~~~~
+
+- Improved error messaging around EOF errors when prompting for code during a command
+  line login flow (:pr:`NUMBER`)

docs/authorization/login_flows.rst

@@ -52,6 +52,9 @@ Example Code:
     :member-order: bysource
     :show-inheritance:
 
+
+.. autoexception:: CommandLineLoginFlowEOFError
+
 Local Server
 ------------
 

src/globus_sdk/login_flows/__init__.py

@@ -1,4 +1,7 @@
-from .command_line_login_flow_manager import CommandLineLoginFlowManager
+from .command_line_login_flow_manager import (
+    CommandLineLoginFlowEOFError,
+    CommandLineLoginFlowManager,
+)
 from .local_server_login_flow_manager import (
     LocalServerEnvironmentalLoginError,
     LocalServerLoginError,
@@ -8,6 +11,7 @@
 
 __all__ = (
     "CommandLineLoginFlowManager",
+    "CommandLineLoginFlowEOFError",
     "LocalServerLoginError",
     "LocalServerEnvironmentalLoginError",
     "LocalServerLoginFlowManager",

src/globus_sdk/login_flows/command_line_login_flow_manager.py

@@ -2,8 +2,10 @@
 
 import textwrap
 import typing as t
+from contextlib import contextmanager
 
 import globus_sdk
+from globus_sdk.exc.base import GlobusError
 from globus_sdk.gare import GlobusAuthorizationParameters
 from globus_sdk.utils import get_nice_hostname
 
@@ -13,6 +15,13 @@
     from globus_sdk.globus_app import GlobusAppConfig
 
 
+class CommandLineLoginFlowEOFError(GlobusError):
+    """
+    An error raised when a CommandLineLoginFlowManager reads an EOF when prompting for
+    a code.
+    """
+
+
 class CommandLineLoginFlowManager(LoginFlowManager):
     """
     A login flow manager which drives authorization-code token grants through the
@@ -128,4 +137,16 @@ def prompt_for_code(self) -> str:
         :returns: The authorization code entered by the user.
         """
         code_prompt = "Enter the resulting Authorization Code here: "
-        return input(code_prompt).strip()
+        with self.handle_input_errors():
+            return input(code_prompt).strip()
+
+    @contextmanager
+    def handle_input_errors(self) -> t.Iterator[None]:
+        try:
+            yield
+        except EOFError as e:
+            msg = (
+                "An EOF was read when an authorization code was expected."
+                " (Are you running this in an interactive terminal?)"
+            )
+            raise CommandLineLoginFlowEOFError(msg) from e

tests/functional/login_flows/test_login_flow_manager.py

@@ -1,12 +1,17 @@
 from unittest.mock import Mock, patch
 
+import pytest
+
 from globus_sdk import ConfidentialAppAuthClient, NativeAppAuthClient
 from globus_sdk._testing import load_response
 from globus_sdk.gare import GlobusAuthorizationParameters
 from globus_sdk.login_flows import (
     CommandLineLoginFlowManager,
     LocalServerLoginFlowManager,
 )
+from globus_sdk.login_flows.command_line_login_flow_manager import (
+    CommandLineLoginFlowEOFError,
+)
 
 
 def _mock_input(s):
@@ -96,6 +101,28 @@ def test_command_line_login_flower_manager_confidential(monkeypatch, capsys):
     assert "&session_required_single_domain=org.edu" in captured_output
 
 
+def test_command_line_login_flow_manager_eof_error(monkeypatch, capsys):
+    """
+    test CommandLineLoginFlowManager with a NativeAppAuthClient
+    """
+    login_client = NativeAppAuthClient("mock_client_id")
+    load_response(login_client.oauth2_exchange_code_for_tokens)
+
+    def broken_input(_s):
+        raise EOFError()
+
+    monkeypatch.setattr("builtins.input", broken_input)
+
+    login_flow_manager = CommandLineLoginFlowManager(login_client)
+    auth_params = GlobusAuthorizationParameters(
+        required_scopes=["urn:globus:auth:scope:transfer.api.globus.org:all"],
+        session_required_identities=["user@org.edu"],
+    )
+
+    with pytest.raises(CommandLineLoginFlowEOFError):
+        login_flow_manager.run_login_flow(auth_params)
+
+
 class MockRedirectServer:
     def __init__(self, *args, **kwargs):
         self.socket = Mock()