fix(remotebuild): use legacy launchpad credentials if they exist

If the legacy remote-build credentials exist and the new credentials do
not, emit a deprecation warning and use the legacy credentials.

Signed-off-by: Callahan Kovacs <callahan.kovacs@canonical.com>

snapcraft/services/remotebuild.py

@@ -15,12 +15,47 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """Snapcraft Lifecycle Service."""
 
+import pathlib
 
+import craft_cli
+import platformdirs
 from craft_application import launchpad
 from craft_application.services import remotebuild
+from typing_extensions import override
 
 
 class RemoteBuild(remotebuild.RemoteBuildService):
     """Snapcraft remote build service."""
 
     RecipeClass = launchpad.models.SnapRecipe
+
+    __credentials_filepath: pathlib.Path | None = None
+
+    @property
+    @override
+    def credentials_filepath(self) -> pathlib.Path:
+        """The filepath to the Launchpad credentials.
+
+        The legacy credentials are only loaded when they exist and the new credentials
+        do not exist. If the legacy credentials are loaded, emit a deprecation warning.
+        """
+        # return early so the deprecation notice is emitted only once
+        if self.__credentials_filepath:
+            return self.__credentials_filepath
+
+        credentials_filepath = super().credentials_filepath
+        legacy_credentials_filepath = (
+            platformdirs.user_data_path("snapcraft") / "provider/launchpad/credentials"
+        )
+
+        if not credentials_filepath.exists() and legacy_credentials_filepath.exists():
+            craft_cli.emit.progress(
+                f"Warning: Using launchpad credentials from deprecated location {str(legacy_credentials_filepath)!r}.\n"
+                f"Credentials should be migrated to {str(credentials_filepath)!r}.",
+                permanent=True,
+            )
+            self.__credentials_filepath = legacy_credentials_filepath
+        else:
+            self.__credentials_filepath = credentials_filepath
+
+        return self.__credentials_filepath

snapcraft_legacy/internal/remote_build/_launchpad.py

@@ -1,6 +1,6 @@
 # -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
 #
-# Copyright (C) 2019 Canonical Ltd
+# Copyright (C) 2019,2024 Canonical Ltd
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
@@ -16,6 +16,8 @@
 
 import gzip
 import logging
+import pathlib
+import platformdirs
 import os
 import shutil
 import time
@@ -111,7 +113,6 @@ def __init__(
 
         self._cache_dir = self._create_cache_directory()
         self._data_dir = self._create_data_directory()
-        self._credentials = os.path.join(self._data_dir, "credentials")
 
         self._lp: Launchpad = self.login()
         self.user = self._lp.me.name
@@ -122,6 +123,25 @@ def __init__(
     def architectures(self) -> Sequence[str]:
         return self._architectures
 
+    @property
+    def _credentials_filepath(self) -> pathlib.Path:
+        """The filepath to the Launchpad credentials.
+
+        If the credentials file does not exist in the default location but exists in the
+        legacy location, emit a deprecation warning and return the legacy location.
+        """
+        credentials_filepath = platformdirs.user_data_path("snapcraft") / "launchpad-credentials"
+        legacy_credentials_filepath = platformdirs.user_data_path("snapcraft") / "provider/launchpad/credentials"
+
+        if not credentials_filepath.exists() and legacy_credentials_filepath.exists():
+            logger.warning(
+                f"Warning: Using launchpad credentials from deprecated location {str(legacy_credentials_filepath)!r}.\n"
+                f"Credentials should be migrated to {str(credentials_filepath)!r}."
+            )
+            return legacy_credentials_filepath
+
+        return credentials_filepath
+
     @architectures.setter
     def architectures(self, architectures: Sequence[str]) -> None:
         self._lp_processors: Optional[Sequence[str]] = None
@@ -256,7 +276,7 @@ def login(self) -> Launchpad:
                 "snapcraft remote-build {}".format(snapcraft_legacy.__version__),
                 "production",
                 self._cache_dir,
-                credentials_file=self._credentials,
+                credentials_file=self._credentials_filepath,
                 version="devel",
             )
         except (ConnectionRefusedError, TimeoutError):

tests/legacy/unit/remote_build/test_launchpad.py

@@ -1,6 +1,6 @@
 # -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
 #
-# Copyright (C) 2019 Canonical Ltd
+# Copyright (C) 2019,2024 Canonical Ltd
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
@@ -16,6 +16,8 @@
 
 import textwrap
 from datetime import datetime, timedelta, timezone
+import pathlib
+import pytest
 from unittest import mock
 
 import fixtures
@@ -535,3 +537,27 @@ def test_push_source_tree_error(self):
         self.assertRaises(
             errors.LaunchpadGitPushError, self.lpc.push_source_tree, repo_dir
         )
+
+
+@pytest.mark.parametrize(
+    ("new_exists", "legacy_exists", "expected"),
+    [
+        (False, False, pathlib.Path("launchpad-credentials")),
+        (False, True, pathlib.Path("provider/launchpad/credentials")),
+        (True, False, pathlib.Path("launchpad-credentials")),
+        (True, True, pathlib.Path("launchpad-credentials")),
+    ],
+)
+def test_credentials_filepaths(new_exists, legacy_exists, expected, mocker, new_dir):
+    """Load legacy credentials only when they exist and the new ones do not."""
+    mocker.patch.object(LaunchpadClient, "__init__", lambda x: None)
+    mocker.patch("platformdirs.user_data_path", return_value=new_dir)
+    if new_exists:
+        (new_dir / "launchpad-credentials").touch()
+    if legacy_exists:
+        (new_dir / "provider/launchpad/credentials").mkdir(parents=True)
+        (new_dir / "provider/launchpad/credentials").touch()
+
+    credentials_filepath = LaunchpadClient()._credentials_filepath
+
+    assert credentials_filepath == new_dir / expected

tests/unit/services/test_remotebuild.py

@@ -0,0 +1,46 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Snapcraft RemoteBuild service tests."""
+
+import pathlib
+
+import pytest
+
+
+@pytest.mark.parametrize(
+    ("new_exists", "legacy_exists", "expected"),
+    [
+        (False, False, pathlib.Path("launchpad-credentials")),
+        (False, True, pathlib.Path("provider/launchpad/credentials")),
+        (True, False, pathlib.Path("launchpad-credentials")),
+        (True, True, pathlib.Path("launchpad-credentials")),
+    ],
+)
+def test_credentials_filepaths(
+    new_exists, legacy_exists, expected, remote_build_service, mocker, new_dir
+):
+    """Load legacy credentials only when they exist and the new ones do not."""
+    mocker.patch("platformdirs.user_data_path", return_value=new_dir)
+    if new_exists:
+        (new_dir / "launchpad-credentials").touch()
+    if legacy_exists:
+        (new_dir / "provider/launchpad/credentials").mkdir(parents=True)
+        (new_dir / "provider/launchpad/credentials").touch()
+
+    credentials_filepath = remote_build_service.credentials_filepath
+
+    assert credentials_filepath == new_dir / expected