hardcharger

Run Hardcharger, GizmoData's DuckDB 2.0 server, from Python. The package has no dependencies: on first use it downloads the hardcharger-server release for your platform (Linux x86-64 and arm64, macOS on Apple silicon), checks it, caches it, and runs it as a subprocess. That makes a real server one line away in tests, notebooks and scripts.

Python package 2.0.1 downloads Hardcharger server 2.0.0 by default.

Quick start

import hardcharger

with hardcharger.Server() as server, server.connect() as conn, conn.cursor() as cur:
    cur.execute(operation="SELECT 42 AS answer, HARDCHARGER_VERSION() AS version")
    print(cur.fetch_arrow_table())

Server() listens on a free port on 127.0.0.1, with an in-memory database and an administrator hardcharger whose password it generates (server.password). The credentials reach the server through its environment, so they don't show in ps.

Hand the server to any other client by its URI:

import hardcharger

with hardcharger.Server(database="analytics.duckdb", password="change-me") as server:
    print(server.uri)  # hardcharger://127.0.0.1:<port>?tls=false
    print(server.username, server.port, server.health_port)

TLS is tls_cert= and tls_key= (the URI drops ?tls=false, and connect() trusts that certificate); any other server option goes in extra_args=[...] or, as HARDCHARGER_* variables, in env={...}. hardcharger-server --help lists them all.

The command line

The package also installs hardcharger-server, which runs the downloaded server:

$ hardcharger-server --version
Hardcharger 0.3.0
$ python -m hardcharger download       # download (if needed) and print the binary's path
/home/me/.cache/hardcharger/v0.3.0/linux-amd64/bin/hardcharger-server

The download

The release comes from gizmodata/hardcharger through the GitHub API. Its SHA-256 must match the digest GitHub recorded for the asset, and the unpacked server must report the expected version, or nothing is installed.

Public releases download anonymously. An optional GitHub token raises the API rate limit: HARDCHARGER_INSTALL_TOKEN, else GH_TOKEN, else the token of a signed-in gh (gh auth token). Set HARDCHARGER_INSTALL_TOKEN=none to force an anonymous download. The token is sent only to the GitHub API, never to the storage host the download is redirected to, and is never printed.

Tests

uv venv && uv pip install -e . --group dev
.venv/bin/python -m pytest -m "not integration and not download"      # no server needed
HARDCHARGER_PY_TEST_SERVER_BINARY=/path/to/hardcharger-server \
  .venv/bin/python -m pytest -m "integration and not client"           # the real server
.venv/bin/python -m pytest -m download                                 # a real download

The client tests also need adbc-driver-hardcharger installed. The integration, client and download tests fail, never skip, without their server, client or GitHub access.

License

Apache License 2.0.

This package is Python only and contains no third-party code. The hardcharger-server it downloads does: its release archive's THIRD_PARTY_NOTICES.md and THIRD_PARTY_NOTICES-web-ui.txt, which the install keeps beside bin/ (~/.cache/hardcharger/v<version>/<platform>/), list that software and its licences, and hardcharger-server --licenses prints them.

_{Built by GizmoData}