Skip to main content

Async http clickhouse client for python 3.6+

Project description

aiochclient

Async http(s) clickhouse client for python 3.6+ with types converting in both directions and streaming support

PyPI version Travis CI Documentation Status codecov Code style: black

Install

> pip install aiochclient

When installing aiochclient will try to build C extensions to boost its speed (about 30% speed up).

Quick start

aiochclient needs aiohttp.ClientSession for connecting:

from aiochclient import ChClient
from aiohttp import ClientSession


async def main():
    async with ClientSession() as s:
        client = ChClient(s)
        assert await client.is_alive()  # returns True if connection is Ok

Query examples

await client.execute(
    "CREATE TABLE t (a UInt8, b Tuple(Date, Nullable(Float32))) ENGINE = Memory"
)

For INSERT queries you can pass values as *args. Values should be iterables.

await client.execute(
    "INSERT INTO t VALUES",
    (1, (dt.date(2018, 9, 7), None)),
    (2, (dt.date(2018, 9, 8), 3.14)),
)

For fetching all rows at once use fetch method:

all_rows = await client.fetch("SELECT * FROM t")

For fetching first row from result use fetchone method:

row = await client.fetchone("SELECT * FROM t WHERE a=1")
assert row == (1, (dt.date(2018, 9, 7), None))

You can also use fetchval method, which returns first value of the first row from query result:

val = await client.fetchval("SELECT b FROM t WHERE a=2")
assert val == (dt.date(2018, 9, 8), 3.14)

Async iteration on query results steam:

async for row in client.cursor(
    "SELECT number, number*2 FROM system.numbers LIMIT 10000"
):
    assert row[0] * 2 == row[1]

ChClient returns rows as tuples.

Use fetch/fetchrow/fetchone for SELECT queries and execute or any of last for INSERT and all another queries.

Types converting

aiochclient automatically converts values to needed type both from Clickhouse response and for client INSERT queries.

Clickhouse type Python type
UInt8 int
UInt16 int
UInt32 int
UInt64 int
Int8 int
Int16 int
Int32 int
Int64 int
Float32 float
Float64 float
String str
FixedString str
Enum8 str
Enum16 str
Date dt.date
DateTime da.datetime
Tuple(T1, T2, ...) tuple(T1, T2, ...)
Array(T) list(T)
UUID uuid.UUID
Nullable(T) None or T
Nothing None

Connection pool

If you use aiochclient in web apps, you can limit connection pool size with aiohttp.TCPConnector.

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

aiochclient-0.1.1.tar.gz (114.5 kB view hashes)

Uploaded Source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page