Improve "No valid Release file found" error message

fixes pulp#399

CHANGES/399.bugfix

@@ -0,0 +1 @@
+Improve the pulp_deb "No valid Release file found" error message for gpg validation fail.

pulp_deb/app/tasks/synchronizing.py

@@ -12,7 +12,7 @@
 from collections import defaultdict
 from tempfile import NamedTemporaryFile
 from debian import deb822
-from urllib.parse import quote, urlparse, urlunparse
+from urllib.parse import quote, urlparse, urlunparse, urljoin
 from django.conf import settings
 from django.db.utils import IntegrityError
 
@@ -75,12 +75,31 @@ class NoReleaseFile(Exception):
     Exception to signal, that no file representing a release is present.
     """
 
-    def __init__(self, distribution, *args, **kwargs):
+    def __init__(self, path, *args, **kwargs):
         """
         Exception to signal, that no file representing a release is present.
         """
         super().__init__(
-            "No valid Release file found for '{}'.".format(distribution), *args, **kwargs
+            "Could not find a Release file at '{}', try checking the 'url' and "
+            "'distributions' option on your remote".format(path),
+            *args,
+            **kwargs,
+        )
+
+
+class NoValidSignatureForKey(Exception):
+    """
+    Exception to signal, that verification of release file with provided GPG key fails.
+    """
+
+    def __init__(self, url, *args, **kwargs):
+        """
+        Exception to signal, that verification of release file with provided GPG key fails.
+        """
+        super().__init__(
+            "Unable to verify any Release files from '{}' using the GPG key provided.".format(url),
+            *args,
+            **kwargs,
         )
 
 
@@ -317,6 +336,7 @@ async def run(self):
 
         Update release content with information obtained from its artifact.
         """
+        dropped_count = 0
         async with ProgressReport(
             message="Update ReleaseFile units", code="update.release_file"
         ) as pb:
@@ -343,6 +363,7 @@ async def run(self):
                                     log.warning(_("Verification of Release failed. Dropping it."))
                                     d_content.d_artifacts.remove(da_names.pop("Release"))
                                     d_content.d_artifacts.remove(da_names.pop("Release.gpg"))
+                                    dropped_count += 1
                             else:
                                 release_file_artifact = da_names["Release"].artifact
                                 release_file.relative_path = da_names["Release"].relative_path
@@ -367,13 +388,18 @@ async def run(self):
                             else:
                                 log.warning(_("Verification of InRelease failed. Dropping it."))
                                 d_content.d_artifacts.remove(da_names.pop("InRelease"))
+                                dropped_count += 1
                         else:
                             release_file_artifact = da_names["InRelease"].artifact
                             release_file.relative_path = da_names["InRelease"].relative_path
 
                     if not d_content.d_artifacts:
                         # No (proper) artifacts left -> distribution not found
-                        raise NoReleaseFile(distribution=release_file.distribution)
+                        if dropped_count > 0:
+                            raise NoValidSignatureForKey(url=self.remote.url)
+                        else:
+                            release_file_path = os.path.dirname(d_content.content.relative_path)
+                            raise NoReleaseFile(path=urljoin(self.remote.url, release_file_path))
 
                     release_file.sha256 = release_file_artifact.sha256
                     release_file.artifact_set_sha256 = _get_artifact_set_sha256(

pulp_deb/tests/functional/api/test_sync.py

@@ -125,7 +125,11 @@ def test_invalid_distribution(self):
         with self.assertRaises(PulpTaskError) as exc:
             self.do_test(distribution="no_dist")
         error = exc.exception.task.error
-        self.assertIn("No valid Release file found", error["description"])
+        self.assertIn(
+            "Could not find a Release file at '{}', try checking the 'url' and "
+            "'distributions' option on your remote".format(DEB_FIXTURE_URL),
+            error["description"],
+        )
 
     def test_missing_package_indices_1(self):
         """Sync a repository missing a set of Package indices.
@@ -163,7 +167,12 @@ def test_invalid_signature(self):
                 distribution="nosuite", url=DEB_INVALID_FIXTURE_URL, gpgkey=DEB_SIGNING_KEY
             )
         error = exc.exception.task.error
-        self.assertIn("No valid Release file found", error["description"])
+        self.assertIn(
+            "Unable to verify any Release files from '{}' using the GPG key provided.".format(
+                DEB_INVALID_FIXTURE_URL
+            ),
+            error["description"],
+        )
 
     def do_test(self, url=DEB_FIXTURE_URL, distribution=DEB_FIXTURE_DISTRIBUTIONS, **kwargs):
         """Sync a repository given ``url`` on the remote."""