Make pulp2 importer optional

closes #6056
closes #5984

CHANGES/5984.bugfix

@@ -0,0 +1 @@
+Add error message for the importers that cannot be migrated.

CHANGES/6056.bugfix

@@ -0,0 +1 @@
+Make pulp2 importer optional.

pulp_2to3_migration/app/json_schema.py

@@ -41,7 +41,7 @@
                                     }
                                 }
                             },
-                            "required": ["name", "pulp2_importer_repository_id", "repository_versions"],
+                            "required": ["name", "repository_versions"],
                             "additionalProperties": false,
                             "$comment": "pulp2_importer_repository_id field should be specified so we know which importer to use when migrating multiple pulp2 repos into repo versions"
                         }

pulp_2to3_migration/app/migration.py

@@ -282,11 +282,19 @@ def create_repo_version(migrator, pulp3_repo_name, pulp2_repo, pulp3_remote=None
         else:
             for repo_name in pulp3_repo_setup:
                 repo_versions_setup = pulp3_repo_setup[repo_name]['repository_versions']
+
+                # importer might not be migrated, e.g. config is empty or it's not specified in a MP
+                pulp3_remote = None
                 pulp2_importer_repo_id = \
-                    pulp3_repo_setup[repo_name]['pulp2_importer_repository_id']
-                pulp2_importer = Pulp2Importer.objects.get(
-                    pulp2_repo_id=pulp2_importer_repo_id
-                )
+                    pulp3_repo_setup[repo_name].get('pulp2_importer_repository_id')
+                if pulp2_importer_repo_id:
+                    try:
+                        pulp2_importer = Pulp2Importer.objects.get(
+                            pulp2_repo_id=pulp2_importer_repo_id
+                        )
+                        pulp3_remote = pulp2_importer.pulp3_remote
+                    except Pulp2Importer.DoesNotExist:
+                        pass
                 for pulp2_repo_info in repo_versions_setup:
                     try:
                         pulp2_repo = Pulp2Repository.objects.get(
@@ -300,5 +308,4 @@ def create_repo_version(migrator, pulp3_repo_name, pulp2_repo, pulp3_remote=None
                         # it's possible to have a random order of the repo versions (after migration
                         # re-run, a repo can be changed in pulp 2 and it might not be for the last
                         # repo version)
-                        create_repo_version(plugin.migrator, repo_name, pulp2_repo,
-                                            pulp2_importer.pulp3_remote)
+                        create_repo_version(plugin.migrator, repo_name, pulp2_repo, pulp3_remote)

pulp_2to3_migration/app/models/base.py

@@ -211,8 +211,9 @@ def _parse_plugin_plan(self, repository_data):
             for repository in repositories:
                 name = repository['name']
 
-                _find_importer_repo = repository['pulp2_importer_repository_id']
-                self.repositories_importers_to_migrate.append(_find_importer_repo)
+                _find_importer_repo = repository.get('pulp2_importer_repository_id')
+                if _find_importer_repo:
+                    self.repositories_importers_to_migrate.append(_find_importer_repo)
 
                 repository_versions = []
                 for repository_version in repository.get('repository_versions', []):

pulp_2to3_migration/app/pre_migration.py

@@ -238,8 +238,13 @@ async def pre_migrate_all_without_content(plan, type_to_repo_ids, repo_id_to_typ
             with transaction.atomic():
                 if not repos or repos and repo_id in repos:
                     repo = await pre_migrate_repo(repo_data, repo_id_to_type)
-                await pre_migrate_importer(repo_id, importers_repos, importer_types, repo)
-                await pre_migrate_distributor(repo_id, distributors_repos, distributor_types, repo)
+                # do not pre-migrate importers/distributors in case of special repo setup
+                # and no importers/distributors were specified in the MP
+                if not repos or repos and importers_repos:
+                    await pre_migrate_importer(repo_id, importers_repos, importer_types, repo)
+                if not repos or repos and distributors_repos:
+                    await pre_migrate_distributor(repo_id, distributors_repos, distributor_types,
+                                                  repo)
                 if repo:
                     await pre_migrate_repocontent(repo)
             pb.increment()
@@ -321,6 +326,9 @@ async def pre_migrate_importer(repo_id, importers, importer_types, repo=None):
 
     if not importer_data.config.get('feed'):
         # Pulp 3 remotes require URL
+        msg = 'Importer from {repo} cannot be migrated because it does not have a feed'.format(
+            repo=repo_id)
+        _logger.warn(msg)
         return
 
     last_updated = (importer_data.last_updated