Add complete field to Publication

Only complete Publications can be distributed.

closes: #3184
https://pulp.plan.io/issues/3184

pulpcore/pulpcore/app/models/publication.py

@@ -6,6 +6,7 @@
 class Publication(Model):
     """
     Fields:
+        complete (models.BooleanField): State tracking; for internal use. Indexed.
         created (models.DatetimeField): When the publication was created UTC.
 
     Relations:
@@ -14,12 +15,18 @@ class Publication(Model):
             create this Publication.
     """
 
+    complete = models.BooleanField(default=False)
     created = models.DateTimeField(auto_now_add=True)
 
     publisher = models.ForeignKey('Publisher', on_delete=models.CASCADE)
 
     repository_version = models.ForeignKey('RepositoryVersion', on_delete=models.CASCADE)
 
+    class Meta:
+        indexes = [
+            models.Index(fields=['complete']),
+        ]
+
 
 class PublishedFile(Model):
     """

pulpcore/pulpcore/app/serializers/repository.py

@@ -226,7 +226,7 @@ class DistributionSerializer(ModelSerializer):
     publication = serializers.HyperlinkedRelatedField(
         allow_null=True,
         help_text=_('The publication being served as defined by this distribution'),
-        queryset=models.Publication.objects.all(),
+        queryset=models.Publication.objects.exclude(complete=False),
         view_name='publications-detail'
     )
     base_url = BaseURLField(

pulpcore/pulpcore/app/viewsets/repository.py

@@ -244,7 +244,7 @@ class PublicationViewSet(GenericNamedModelViewSet,
                          mixins.ListModelMixin,
                          mixins.DestroyModelMixin):
     endpoint_name = 'publications'
-    queryset = Publication.objects.all()
+    queryset = Publication.objects.exclude(complete=False)
     serializer_class = PublicationSerializer