storage: add new tombstone_repo method

...and implement in `MemoryStorage` and `DatastoreStorage`. Used to delete accounts: bluesky-social/atproto#2503 (comment) . for snarfed/bridgy-fed#783

README.md

@@ -126,6 +126,8 @@ _Non-breaking changes:_
 
 * Bug fix: base32-encode TIDs in record keys, `at://` URIs, commit `rev`s, etc. Before, we were using the integer UNIX timestamp directly, which happened to be the same 13 character length. Oops.
 * Switch from `BGS_HOST` environment variable to `RELAY_HOST`. `BGS_HOST` is still supported for backward compatibility.
+* `storage`:
+  * Add new `Storage.tombstone_repo` method, implement in `MemoryStorage` and `DatastoreStorage`. [Used to delete accounts.](https://github.com/bluesky-social/atproto/discussions/2503#discussioncomment-9502339) ([bridgy-fed#783](https://github.com/snarfed/bridgy-fed/issues/783))
 * `datastore_storage`:
   * Bug fix for `DatastoreStorage.last_seq`, handle new NSID.
   * Add new `AtpRemoteBlob` class for storing "remote" blobs, available at public HTTP URLs, that we don't store ourselves.

arroba/datastore_storage.py

@@ -17,7 +17,7 @@
 from .repo import Repo
 from . import storage
 from .storage import Action, Block, Storage, SUBSCRIBE_REPOS_NSID
-from .util import dag_cbor_cid, tid_to_int
+from .util import dag_cbor_cid, tid_to_int, TOMBSTONED, TombstonedRepo
 
 logger = logging.getLogger(__name__)
 
@@ -80,7 +80,7 @@ class CommitOp(ndb.Model):
 
     https://googleapis.dev/python/python-ndb/latest/model.html#google.cloud.ndb.model.StructuredProperty
     """
-    action = ndb.StringProperty(required=True, choices=['create', 'update', 'delete'])
+    action = ndb.StringProperty(required=True, choices=('create', 'update', 'delete'))
     path = ndb.StringProperty(required=True)
     cid = ndb.StringProperty()  # unset for deletes
 
@@ -96,6 +96,7 @@ class AtpRepo(ndb.Model):
     * head (str): CID
     * signing_key (str)
     * rotation_key (str)
+    * status (str)
     """
     handles = ndb.StringProperty(repeated=True)
     head = ndb.StringProperty(required=True)
@@ -107,6 +108,7 @@ class AtpRepo(ndb.Model):
     # TODO: rename this recovery_key_pem?
     # https://discord.com/channels/1097580399187738645/1098725036917002302/1153447354003894372
     rotation_key_pem = ndb.BlobProperty()
+    status = ndb.StringProperty(choices=(TOMBSTONED,))
 
     created = ndb.DateTimeProperty(auto_now_add=True)
     updated = ndb.DateTimeProperty(auto_now=True)
@@ -411,6 +413,8 @@ def load_repo(self, did_or_handle):
         if not atp_repo:
             logger.info(f"Couldn't find repo for {did_or_handle}")
             return None
+        elif atp_repo.status == TOMBSTONED:
+            raise TombstonedRepo(f'{atp_repo.key} is tombstoned')
 
         logger.info(f'Loading repo {atp_repo.key}')
         self.head = CID.decode(atp_repo.head)
@@ -420,6 +424,19 @@ def load_repo(self, did_or_handle):
                          signing_key=atp_repo.signing_key,
                          rotation_key=atp_repo.rotation_key)
 
+    @ndb_context
+    def tombstone_repo(self, repo):
+        @ndb.transactional()
+        def update():
+            atp_repo = AtpRepo.get_by_id(repo.did)
+            atp_repo.status = TOMBSTONED
+            atp_repo.put()
+
+        update()
+
+        if repo.callback:
+            repo.callback(None)  # TODO: format tombstone event
+
     @ndb_context
     def read(self, cid):
         block = AtpBlock.get_by_id(cid.encode('base32'))

arroba/repo.py

@@ -76,6 +76,7 @@ class Repo:
     callback = None
     signing_key = None
     rotation_key = None
+    status = None
 
     def __init__(self, *, storage=None, mst=None, head=None, handle=None,
                  callback=None, signing_key=None, rotation_key=None):

arroba/storage.py

@@ -10,7 +10,7 @@
 from multiformats import CID, multicodec, multihash
 
 from . import util
-from .util import dag_cbor_cid, tid_to_int
+from .util import dag_cbor_cid, tid_to_int, TOMBSTONED, TombstonedRepo
 
 SUBSCRIBE_REPOS_NSID = 'com.atproto.sync.subscribeRepos'
 
@@ -151,6 +151,20 @@ def load_repo(self, did_or_handle):
 
         Returns:
           Repo, or None if the did or handle wasn't found:
+
+        Raises:
+          TombstonedRepo: if the repo is tombstoned
+        """
+        raise NotImplementedError()
+
+    def tombstone_repo(self, repo):
+        """Marks a repo as tombstoned.
+
+        After this, :meth:`load_repo` will raise :class:`TombstonedRepo` for
+        this repo.
+
+        Args:
+          repo (Repo)
         """
         raise NotImplementedError()
 
@@ -329,8 +343,13 @@ def load_repo(self, did_or_handle):
 
         for repo in self.repos:
             if did_or_handle in (repo.did, repo.handle):
+                if repo.status == TOMBSTONED:
+                    raise TombstonedRepo(f'{repo.did} is tombstoned')
                 return repo
 
+    def tombstone_repo(self, repo):
+        repo.status = TOMBSTONED
+
     def read(self, cid):
         return self.blocks.get(cid)
 

arroba/tests/test_datastore_storage.py

@@ -19,7 +19,7 @@
 )
 from ..repo import Action, Repo, Write
 from ..storage import Block, CommitData, MemoryStorage, SUBSCRIBE_REPOS_NSID
-from ..util import dag_cbor_cid, new_key, next_tid
+from ..util import dag_cbor_cid, new_key, next_tid, TOMBSTONED, TombstonedRepo
 
 from . import test_repo
 from .testutil import DatastoreTest, requests_response
@@ -80,10 +80,19 @@ def test_create_load_repo(self):
     def test_create_load_repo_no_handle(self):
         repo = Repo.create(self.storage, 'did:web:user.com', signing_key=self.key,
                            rotation_key=self.key)
-        # self.storage.create_repo(repo)
         self.assertEqual([], AtpRepo.get_by_id('did:web:user.com').handles)
         self.assertIsNone(self.storage.load_repo('han.dull'))
 
+    def test_tombstone_repo(self):
+        repo = Repo.create(self.storage, 'did:user', signing_key=self.key)
+        self.assertIsNone(AtpRepo.get_by_id('did:user').status)
+
+        self.storage.tombstone_repo(repo)
+        self.assertEqual(TOMBSTONED, AtpRepo.get_by_id('did:user').status)
+
+        with self.assertRaises(TombstonedRepo):
+            self.storage.load_repo('did:user')
+
     def test_atp_block_create(self):
         data = {'foo': 'bar'}
         AtpBlock.create(repo_did='did:web:user.com', data=data, seq=1)

arroba/tests/test_storage.py

@@ -4,9 +4,9 @@
 import dag_cbor
 from multiformats import CID
 
-from ..util import next_tid
 from ..repo import Repo, Write
 from ..storage import Action, Block, MemoryStorage
+from ..util import next_tid, TOMBSTONED, TombstonedRepo
 
 from .testutil import TestCase
 
@@ -76,3 +76,13 @@ def test_read_commits_by_seq_include_record_block_even_if_preexisting(self):
 
         record = Block(decoded={'foo': 'bar'})
         self.assertEqual(record, commits[0].blocks[record.cid])
+
+    def test_tombstone_repo(self):
+        storage = MemoryStorage()
+        repo = Repo.create(storage, 'did:user', signing_key=self.key)
+        storage.tombstone_repo(repo)
+
+        self.assertEqual(TOMBSTONED, repo.status)
+
+        with self.assertRaises(TombstonedRepo):
+            storage.load_repo('did:user')

arroba/util.py

@@ -40,6 +40,11 @@
     ec.SECP256K1: 0xFFFFFFFF_FFFFFFFF_FFFFFFFF_FFFFFFFE_BAAEDCE6_AF48A03B_BFD25E8C_D0364141
 }
 
+TOMBSTONED = 'tombstoned'
+
+class TombstonedRepo(Exception):
+    pass
+
 
 def now(tz=timezone.utc, **kwargs):
     """Wrapper for :meth:`datetime.datetime.now` that lets us mock it out in tests."""