Skip to content

Repository files navigation

image image image image build image CodeQL image ty

GraphQL service for ibis tables. Ibis supports 20+ backends — DuckDB, PostgreSQL, Polars, BigQuery, etc. — so the same query API works across local files and remote databases. The schema is derived automatically.

Parquet datasets are also supported as a root source, with custom optimizations for partitions. As of version 2, execution is based on ibis (default backend: DuckDB).

Usage

There is an example app which reads a parquet dataset.

env PARQUET_PATH=... uvicorn graphique.service:app

Open http://localhost:8000/ to try out the API in GraphiQL. There is a test fixture at ./tests/fixtures/zipcodes.parquet.

env PARQUET_PATH=... strawberry export-schema graphique.service:app.schema

outputs the graphql schema.

Configuration

The example app uses Starlette's config: in environment variables or a .env file.

  • PARQUET_PATH: path to the parquet directory or file
  • NAME = '': GraphQL field on Query; defaults to root type
  • COLUMNS = None: list of names, or mapping of aliases, of columns to select

Configuration options exist to provide a convenient no-code solution, but are subject to change in the future. Using a custom app is recommended for production usage.

App

For more options create a custom ASGI app. Call graphique's GraphQL on an ibis Table or parquet Dataset. Use a Query type with dataset attributes for multiple roots, and to enable federation.

import ibis
from graphique import GraphQL, typed

# any ibis backend: DuckDB, PostgreSQL, Polars, BigQuery, ...
source = ibis.read_(...)  # or `ibis.connect(...).table(...)` or `pyarrow.dataset.dataset(...)`
# apply initial projections or filters to `source`
app = GraphQL(source)  # Table is root query type


# multiple named fields, with optional federation keys
class Query:
    name = source  # or `typed(source, name, keys=...)`


app = GraphQL(Query)

Start like any ASGI app.

uvicorn <module>:app

API

types

  • Dataset: interface for an ibis table or parquet dataset.
  • Table: implements the Dataset interface. Adds typed row, columns, and filter fields from introspecting the schema.
  • Column: interface for an ibis column. Each data type has a corresponding column implementation: Boolean, Int, BigInt, Float, Decimal, Date, Datetime, Time, Duration, Base64, String, Array, Struct. All columns have a values field for their list of scalars. Additional fields vary by type.
  • Row: scalar fields. Tables are column-oriented, and graphique encourages that usage for performance. A single row field is provided for convenience, but a field for a list of rows is not. Requesting parallel columns is far more efficient.

selection

  • slice: contiguous selection of rows
  • filter: select rows by predicates
  • join, asofJoin, crossJoin: join tables by key columns
  • difference, intersect, union: set operations on tables
  • take: rows by index
  • dropNull: remove rows with nulls

projection

  • project: project columns with expressions
  • columns: provides a field for every Column in the schema
  • column: access a column of any type by name
  • row: provides a field for each scalar of a single row
  • cast: cast column types
  • unpack: project struct fields
  • fillNull: fill null values

aggregation

  • group: group by given columns, and aggregate the others
  • distinct: group with all columns
  • runs: group by adjacency
  • unnest: unnest an array column
  • count, any: number of rows

ordering

  • order: sort table by given columns
  • first: sort and filter by rank

reflection

  • type: type of data source
  • schema: field names and types
  • optional: nullable for errors
  • toSql: compiles SQL query

Performance

Performance is dependent on the Ibis backend, which defaults to DuckDB. There are no internal Python loops. Scalars do not become Python types until serialized. Table fields are lazily evaluated up until scalars are reached, and automatically cached as needed for multiple fields.

PyArrow is also used for partitioned dataset optimizations. python -m graphique.partition is a command-line script provided in graphique[cli], for out-of-core partitioning.

Installation

pip install graphique[server,cli]

Dependencies

  • ibis-framework (with duckdb or other backend)
  • strawberry-graphql[asgi,cli]
  • pyarrow
  • isodate
  • uvicorn (or other ASGI server)

Tests

100% branch coverage.

pytest [--cov]

About

GraphQL service for python dataframes and parquet datasets.

Topics

Resources

Stars

94 stars

Watchers

3 watching

Forks

Releases

Packages

Used by

Contributors

Languages