Gannoy

Approximate nearest neighbor search server and dynamic index written in Golang. Gannoy is inspired by spotify/annoy and provides a dynamic database and API server.

Quick start

# Create database
$ gannoy create -d 100 DATABASE_NAME
# Start server
$ gannoy-db

Regiter features using gannoy API.

$ curl 'http://localhost:1323/databases/DATABASE_NAME/features/KEY' \
       -H "Content-type: application/json" \
       -X PUT \
       -d '{"features": [1.0, 0.5, 0.2, ...]}'

Search similar items.

$ curl 'http://localhost:1323/search?database=DATABASE_NAME&key=KEY'
[10, 23, 2, 20, 300, 45, 11, 8, 39, 88]

See also gannoy create --help or gannoy-db --help.

Install

$ go get github.com/monochromegane/gannoy/...

Recommendation environment is Linux (kernel >= 3.15.0).

Gannoy uses fcntl system call and F_OFD_SETLKW command to lock the necessary minimum range from multiple goroutines for speeding up.

API

GET /search

Search approximate nearest neighbor items.

query parameters

key	value
database	Search for similar items from this database name.
key	Search for similar items from this key's feature.
limit	Maxium number of result.

Response

• Response 200 (application/json)
  • return list of item keys.
• Response 404 (no content)
  • return no content if you specify not found database or key.

POST /databases/:database/features

Register features using a specified key.

URI parameters

key	value
database	Create item in this database name.

JSON parameters

key	value
key	Create item using this key.
features	List of feature value.

Note: KEY must be integer.

Response

• Response 200 (no content)
  • return no content.
• Response 422 (no content)
  • return no content if you specify not found database or unprocessable parameter.

PUT /databases/:database/features/:key

Register or update features using a specified key.

URI parameters

key	value
database	Create or update item in this database name.
key	Create or update item using this key.

Note: KEY must be integer.

JSON parameters

key	value
features	List of feature value.

Response

• Response 200 (no content)
  • return no content.
• Response 422 (no content)
  • return no content if you specify not found database or unprocessable parameter.

DELETE /databases/:database/features/:key

Register or update features using a specified key.

URI parameters

key	value
database	Delete item from this database name.
key	Delete item using this key.

Response

• Response 200 (no content)
  • return no content.
• Response 422 (no content)
  • return no content if you specify not found database or unprocessable parameter.

Run with Server::Starter

Gannoy can run with Server::Starter for supporting graceful restart.

$ start_server --port 8080 --pid-file app.pid -- gannoy-db -s # gannoy-db listen Server::Starter port if you pass s option.

Configuration

Gannoy can load option from configuration file.

If you prepare a configuration file named gannoy.toml like the following:

data-dir = "/var/lib/gannoy"
log-dir  = "/var/log/gannoy"
lock-dir = "/var/run/gannoy"
server-starter = true

You can specify the name with c option.

$ gannoy-db -c gannoy.toml

Note: A priority of flag is command-line flag > configration file > flag default value. See also monochromegane/conflag.

Building rpm

Note: Requirements are Docker and docker-compose.

$ docker-compose build gannoy-rpmbuild
$ docker-compose run gannoy-rpmbuild

Result (gannoy-x.x.x-x.x86_64.rpm) is put in rpmbuild/RPMS/x86_64 directory on host.

You can install the rpm and running gannoy-db process on CentOS.

$ sudo rpm -ivh gannoy-x.x.x-x.x86_64.rpm
$ sudo systemctl start gannoy-db

Data migration from annoy

You can migrate spotify/annoy database file.

$ gannoy-converter -d 100 ANNOY_FILE DATABASE_NAME

License

MIT

Author

monochromegane