Astra DB
DataStax Astra DB is a serverless vector-capable database built on Cassandra and made conveniently available through an easy-to-use JSON API.
AstraDBStore
and AstraDBByteStore
need the astrapy
package to be installed:
%pip install --upgrade --quiet astrapy
The Store takes the following parameters:
api_endpoint
: Astra DB API endpoint. Looks likehttps://01234567-89ab-cdef-0123-456789abcdef-us-east1.apps.astra.datastax.com
token
: Astra DB token. Looks likeAstraCS:6gBhNmsk135....
collection_name
: Astra DB collection namenamespace
: (Optional) Astra DB namespace
AstraDBStore
The AstraDBStore
is an implementation of BaseStore
that stores everything in your DataStax Astra DB instance.
The store keys must be strings and will be mapped to the _id
field of the Astra DB document.
The store values can be any object that can be serialized by json.dumps
.
In the database, entries will have the form:
{
"_id": "<key>",
"value": <value>
}
from langchain_community.storage import AstraDBStore
API Reference:
from getpass import getpass
ASTRA_DB_API_ENDPOINT = input("ASTRA_DB_API_ENDPOINT = ")
ASTRA_DB_APPLICATION_TOKEN = getpass("ASTRA_DB_APPLICATION_TOKEN = ")
store = AstraDBStore(
api_endpoint=ASTRA_DB_API_ENDPOINT,
token=ASTRA_DB_APPLICATION_TOKEN,
collection_name="my_store",
)
store.mset([("k1", "v1"), ("k2", [0.1, 0.2, 0.3])])
print(store.mget(["k1", "k2"]))
['v1', [0.1, 0.2, 0.3]]
Usage with CacheBackedEmbeddings
You may use the AstraDBStore
in conjunction with a CacheBackedEmbeddings
to cache the result of embeddings computations.
Note that AstraDBStore
stores the embeddings as a list of floats without converting them first to bytes so we don't use fromByteStore
there.
from langchain.embeddings import CacheBackedEmbeddings, OpenAIEmbeddings
embeddings = CacheBackedEmbeddings(
underlying_embeddings=OpenAIEmbeddings(), document_embedding_store=store
)
API Reference:
AstraDBByteStore
The AstraDBByteStore
is an implementation of ByteStore
that stores everything in your DataStax Astra DB instance.
The store keys must be strings and will be mapped to the _id
field of the Astra DB document.
The store bytes
values are converted to base64 strings for storage into Astra DB.
In the database, entries will have the form:
{
"_id": "<key>",
"value": "bytes encoded in base 64"
}
from langchain_community.storage import AstraDBByteStore
API Reference:
from getpass import getpass
ASTRA_DB_API_ENDPOINT = input("ASTRA_DB_API_ENDPOINT = ")
ASTRA_DB_APPLICATION_TOKEN = getpass("ASTRA_DB_APPLICATION_TOKEN = ")
store = AstraDBByteStore(
api_endpoint=ASTRA_DB_API_ENDPOINT,
token=ASTRA_DB_APPLICATION_TOKEN,
collection_name="my_store",
)
store.mset([("k1", b"v1"), ("k2", b"v2")])
print(store.mget(["k1", "k2"]))
[b'v1', b'v2']