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Version: 1.14.1 (latest)

Custom destination with LanceDB

info

The source code for this example can be found in our repository at: https://github.com/dlt-hub/dlt/tree/devel/docs/examples/custom_destination_lancedb

About this Example

This example showcases a Python script that demonstrates the integration of LanceDB, an open-source vector database, as a custom destination within the dlt ecosystem. The script illustrates the implementation of a custom destination as well as the population of the LanceDB vector store with data from various sources. This highlights the seamless interoperability between dlt and LanceDB.

You can get a Spotify client ID and secret from https://developer.spotify.com/.

We'll learn how to:

Full source code

__source_name__ = "spotify"

import datetime # noqa: I251
from dataclasses import dataclass, fields
import os
from pathlib import Path
from typing import Any

import lancedb
from lancedb.embeddings import get_registry
from lancedb.pydantic import LanceModel, Vector

import dlt
from dlt.common.configuration import configspec
from dlt.common.schema import TTableSchema
from dlt.common.typing import TDataItems, TSecretStrValue
from dlt.sources.helpers import requests
from dlt.sources.helpers.rest_client import RESTClient, AuthConfigBase

# access secrets to get openai key
openai_api_key: str = dlt.secrets.get(
"destination.lancedb.credentials.embedding_model_provider_api_key"
)
# usually the api-key would be provided to the embedding function via the registry, but there
# currently is a bug: https://github.com/lancedb/lancedb/issues/2387
registry = get_registry()
registry.set_var("openai_api_key", openai_api_key)
# create the embedding function
func = (
get_registry()
.get("openai")
.create(
name="text-embedding-3-small",
# api_key="$var:api_key" # << currently broken
)
)
# so instead we provide it via environment variable
os.environ["OPENAI_API_KEY"] = openai_api_key


class EpisodeSchema(LanceModel):
id: str # noqa: A003
name: str
description: str = func.SourceField()
vector: Vector(func.ndims()) = func.VectorField() # type: ignore[valid-type]
release_date: datetime.date
audio_preview_url: str
duration_ms: int
href: str
uri: str
# there is more data but we are not using it ...


@dataclass(frozen=True)
class Shows:
monday_morning_data_chat: str = "3Km3lBNzJpc1nOTJUtbtMh"
superdatascience_podcast: str = "1n8P7ZSgfVLVJ3GegxPat1"
lex_fridman: str = "2MAi0BvDc6GTFvKFPXnkCL"


@configspec
class SpotifyAuth(AuthConfigBase):
client_id: str = None
client_secret: TSecretStrValue = None

def __call__(self, request) -> Any:
if not hasattr(self, "access_token"):
self.access_token = self._get_access_token()
request.headers["Authorization"] = f"Bearer {self.access_token}"
return request

def _get_access_token(self) -> Any:
auth_url = "https://accounts.spotify.com/api/token"
auth_response = requests.post(
auth_url,
{
"grant_type": "client_credentials",
"client_id": self.client_id,
"client_secret": self.client_secret,
},
)
return auth_response.json()["access_token"]


@dlt.source
def spotify_shows(
client_id: str = dlt.secrets.value,
client_secret: str = dlt.secrets.value,
):
spotify_base_api_url = "https://api.spotify.com/v1"
client = RESTClient(
base_url=spotify_base_api_url,
auth=SpotifyAuth(client_id=client_id, client_secret=client_secret),
)

for show in fields(Shows):
show_name = show.name
show_id = show.default
url = f"/shows/{show_id}/episodes"
yield dlt.resource(
client.paginate(url, params={"limit": 50}),
name=show_name,
write_disposition="merge",
primary_key="id",
parallelized=True,
max_table_nesting=0,
)


@dlt.destination(batch_size=250, name="lancedb")
def lancedb_destination(items: TDataItems, table: TTableSchema) -> None:
db_path = Path(dlt.config.get("lancedb.db_path"))
db = lancedb.connect(db_path)

try:
tbl = db.open_table(table["name"])
except ValueError:
tbl = db.create_table(table["name"], schema=EpisodeSchema)

# remove all fields that are not in the schema
for item in items:
keys_to_remove = [key for key in item.keys() if key not in EpisodeSchema.model_fields]
for key in keys_to_remove:
del item[key]

tbl.add(items)


if __name__ == "__main__":
db_path = Path(dlt.config.get("lancedb.db_path"))
db = lancedb.connect(db_path)

for show in fields(Shows):
try:
db.drop_table(show.name)
except ValueError:
# table is not there
pass

pipeline = dlt.pipeline(
pipeline_name="spotify",
destination=lancedb_destination,
dataset_name="spotify_podcast_data",
progress="log",
)

load_info = pipeline.run(spotify_shows())
print(load_info)

row_counts = pipeline.last_trace.last_normalize_info
print(row_counts)

query = "French AI scientist with Lex, talking about AGI and Meta and Llama"
table_to_query = "lex_fridman"

tbl = db.open_table(table_to_query)

results = tbl.search(query=query).to_list()
assert results

This demo works on codespaces. Codespaces is a development environment available for free to anyone with a Github account. You'll be asked to fork the demo repository and from there the README guides you with further steps.
The demo uses the Continue VSCode extension.

Off to codespaces!

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