arroba 0.5

Python implementation of Bluesky PDS and AT Protocol, including repo, MST, and sync methods

arroba

Python implementation of Bluesky PDS and AT Protocol, including data repository, Merkle search tree, and com.atproto.sync XRPC methods.

You can build your own PDS on top of arroba with just a few lines of Python and run it in any WSGI server. You can build a more involved PDS with custom logic and behavior. Or you can build a different ATProto service, eg an AppView, relay (née BGS), or something entirely new!

Install from PyPI with pip install arroba.

Arroba is the Spanish word for the @ character ("at sign").

License: This project is placed in the public domain. You may also use it under the CC0 License.

• Usage
• Overview
• Configuration
• Docs
• Changelog
• Release instructions

Usage

Here's minimal example code for a multi-repo PDS on top of arroba and Flask:

from flask import Flask
from google.cloud import ndb
from lexrpc.flask_server import init_flask

from arroba import server
from arroba.datastore_storage import DatastoreStorage
from arroba.xrpc_sync import send_new_commits

server.storage = DatastoreStorage()
server.repo.callback = lambda _: send_new_commits()  # to subscribeRepos

app = Flask('my-pds')
init_flask(server.server, app)

# for Google Cloud Datastore
ndb_client = ndb.Client()

def ndb_context_middleware(wsgi_app):
    def wrapper(environ, start_response):
        with ndb_client.context():
            return wsgi_app(environ, start_response)
    return wrapper

app.wsgi_app = ndb_context_middleware(app.wsgi_app)

See app.py for a more comprehensive example, including a CORS handler for OPTIONS preflight requests and a catch-all app.bsky.* XRPC handler that proxies requests to the AppView.

Overview

Arroba consists of these parts:

• Data structures:
  • Repo
  • MST (Merkle search tree)
• Storage:
  • Storage abstract base class
  • DatastoreStorage (uses Google Cloud Datastore)
  • TODO: filesystem storage
• XRPC handlers:
  • com.atproto.repo
  • com.atproto.server
  • com.atproto.sync
• Utilities:
  • did: create and resolve did:plcs, did:webs, and domain handles
  • diff: find the deterministic minimal difference between two MSTs
  • util: miscellaneous utilities for TIDs, AT URIs, signing and verifying signatures, generating JWTs, encoding/decoding, and more

Configuration

Configure arroba with these environment variables:

• APPVIEW_HOST, default api.bsky-sandbox.dev
• RELAY_HOST, default bgs.bsky-sandbox.dev
• PLC_HOST, default plc.bsky-sandbox.dev
• PDS_HOST, where you're running your PDS

Optional, only used in com.atproto.repo and com.atproto.server XRPC handlers:

• REPO_TOKEN, static token to use as both accessJwt and refreshJwt, defaults to contents of repo_token file. Not required to be an actual JWT. If not set, XRPC methods that require auth will return HTTP 501 Not Implemented.

Changelog

0.5 - 2024-03-16

• Bug fix: base32-encode TIDs in record keys, at:// URIs, commit revs, 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.
• 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.
• did:
  • create_plc: strip padding from genesis operation signature (for did-method-plc#54, atproto#1839).
  • resolve_handle: return None on bad domain, eg .foo.com.
  • resolve_handle bug fix: handle charset specifier in HTTPS method response Content-Type.
• util:
  • new_key: add seed kwarg to allow deterministic key generation.
• xrpc_repo:
  • getRecord: try to load record locally first; if not available, forward to AppView.
• xrpc_sync:
  • Implement getBlob, right now only based on "remote" blobs stored in AtpRemoteBlobs in datastore storage.

0.4 - 2023-09-19

• Migrate to ATProto repo v3. Specifically, the existing subscribeRepos sequence number is reused as the new rev field in commits. (Discussion.).
• Add new did module with utilities to create and resolve did:plcs and resolve did:webs.
• Add new util.service_jwt function that generates ATProto inter-service JWTs.
• Repo:
  • Add new signing_key/rotation_key attributes. Generate store, and load both in datastore_storage.
  • Remove format_init_commit, migrate existing calls to format_commit.
• Storage:
  • Rename read_from_seq => read_blocks_by_seq (and in MemoryStorage and DatastoreStorage), add new read_commits_by_seq method.
  • Merge load_repo did/handle kwargs into did_or_handle.
• XRPCs:
  • Make subscribeRepos check storage for all new commits every time it wakes up.
    • As part of this, replace xrpc_sync.enqueue_commit with new send_new_commits function that takes no parameters.
  • Drop bundled app.bsky/com.atproto lexicons, use lexrpc's instead.

0.3 - 2023-08-29

Big milestone: arroba is successfully federating with the ATProto sandbox! See app.py for the minimal demo code needed to wrap arroba in a fully functional PDS.

• Add Google Cloud Datastore implementation of repo storage.
• Implement com.atproto XRPC methods needed to federate with sandbox, including most of repo and sync.
  • Notably, includes subscribeRepos server side over websocket.
• ...and much more.

0.2 - 2023-05-18

Implement repo and commit chain in new Repo class, including pluggable storage. This completes the first pass at all PDS data structures. Next release will include initial implementations of the com.atproto.sync.* XRPC methods.

0.1 - 2023-04-30

Initial release! Still very in progress. MST, Walker, and Diff classes are mostly complete and working. Repo, commits, and sync XRPC methods are still in progress.

Release instructions

Here's how to package, test, and ship a new release.

1. Run the unit tests.

   source local/bin/activate.csh
   python3 -m unittest discover
   

2. Bump the version number in pyproject.toml and docs/conf.py. git grep the old version number to make sure it only appears in the changelog. Change the current changelog entry in README.md for this new version from unreleased to the current date.

3. Build the docs. If you added any new modules, add them to the appropriate file(s) in docs/source/. Then run ./docs/build.sh. Check that the generated HTML looks fine by opening docs/_build/html/index.html and looking around.

4. setenv ver X.Y
   git commit -am "release v$ver"
   

5. Upload to test.pypi.org for testing.

   python3 -m build
   twine upload -r pypitest dist/arroba-$ver*
   

6. Install from test.pypi.org.

   cd /tmp
   python3 -m venv local
   source local/bin/activate.csh
   # make sure we force pip to use the uploaded version
   pip3 uninstall arroba
   pip3 install --upgrade pip
   pip3 install -i https://test.pypi.org/simple --extra-index-url https://pypi.org/simple arroba==$ver
   deactivate
   

7. Smoke test that the code trivially loads and runs.

   source local/bin/activate.csh
   python3
   # TODO: test code
   deactivate
   

8. Tag the release in git. In the tag message editor, delete the generated comments at bottom, leave the first line blank (to omit the release "title" in github), put ### Notable changes on the second line, then copy and paste this version's changelog contents below it.

   git tag -a v$ver --cleanup=verbatim
   git push && git push --tags
   

9. Click here to draft a new release on GitHub. Enter vX.Y in the Tag version box. Leave Release title empty. Copy ### Notable changes and the changelog contents into the description text box.

10. Upload to pypi.org!

    twine upload dist/arroba-$ver*
    

11. Wait for the docs to build on Read the Docs, then check that they look ok.

12. On the Versions page, check that the new version is active, If it's not, activate it in the Activate a Version section.