Quickstart

Introduction

This guide explains how to set up the Snowflake emulator and develop a Python program using the Snowflake Connector for Python (snowflake-connector-python) to interact with emulated Snowflake running on your local machine.

Prerequisites

• localstack CLI
• LocalStack for Snowflake
• Python 3.10 or later
• snowflake-connector-python library

Instructions

Before you begin, pull the Snowflake emulator image (localstack/snowflake) and start the container:

export LOCALSTACK_AUTH_TOKEN=<your_auth_token>
IMAGE_NAME=localstack/snowflake:latest localstack start

Check the emulator’s availability by running:

curl -d '{}' snowflake.localhost.localstack.cloud:4566/session

The response should be:

{"success": true}

Connect to the Snowflake emulator

Create a new Python file named main.py and use the following code to connect to the Snowflake emulator:

import snowflake.connector as sf

sf_conn_obj = sf.connect(
    user="test",
    password="test",
    account="test",
    database="test",
    host="snowflake.localhost.localstack.cloud",
)

Specify the host parameter as snowflake.localhost.localstack.cloud and the other parameters as test to avoid connecting to the real Snowflake instance.

Create and execute a query

Extend the Python program to insert rows from a list object into the emulated Snowflake table. Create a cursor object and execute the query:

print("1. Insert lot of rows from a list object to Snowflake table")
print("2. Creating a cursor object")
sf_cur_obj = sf_conn_obj.cursor()

print("3. Executing a query on cursor object")
try:
    sf_cur_obj.execute(
        "create or replace table "
        "ability(name string, skill string )")

    rows_to_insert = [('John', 'SQL'), ('Alex', 'Java'), ('Pete', 'Snowflake')]

    sf_cur_obj.executemany(
        " insert into ability (name, skill) values (%s,%s) " ,rows_to_insert)

    sf_cur_obj.execute("select name, skill from ability")

    print("4. Fetching the results")
    result = sf_cur_obj.fetchall()
    print("Total # of rows :" , len(result))
    print("Row-1 =>",result[0])
    print("Row-2 =>",result[1])
finally:
    sf_cur_obj.close()

This program creates a table named ability, inserts rows, and fetches the results.

Run the Python program

Execute the Python program with:

python main.py

The output should be:

Insert lot of rows from a list object to Snowflake table
1. Insert lot of rows from a list object to Snowflake table
2. Creating a cursor object
3. Executing a query on cursor object
4. Fetching the results
Total # of rows : 3
Row-1 => ('John', 'SQL')
Row-2 => ('Alex', 'Java')

Verify the results by navigating to the LocalStack logs:

2024-02-22T06:03:13.627  INFO --- [   asgi_gw_0] localstack.request.http    : POST /session/v1/login-request => 200
2024-02-22T06:03:16.122  WARN --- [   asgi_gw_0] l.packages.core            : postgresql will be installed as an OS package, even though install target is _not_ set to be static.
2024-02-22T06:03:45.917  INFO --- [   asgi_gw_0] localstack.request.http    : POST /queries/v1/query-request => 200
2024-02-22T06:03:46.016  INFO --- [   asgi_gw_1] localstack.request.http    : POST /queries/v1/query-request => 200
2024-02-22T06:03:49.361  INFO --- [   asgi_gw_0] localstack.request.http    : POST /queries/v1/query-request => 200
2024-02-22T06:03:49.412  INFO --- [   asgi_gw_1] localstack.request.http    : POST /session => 200

Destroy the local infrastructure

To stop LocalStack and remove locally created resources, use:

localstack stop

LocalStack is ephemeral and doesn’t persist data across restarts. It runs inside a Docker container, and once it’s stopped, all locally created resources are automatically removed. In a future release of the Snowflake emulator, we will provide proper persistence and integration with a Cloud Pods feature as well.

Next steps

You can now explore the following resources to learn more about the Snowflake emulator:

• Features: Learn about the Snowflake emulator’s features and how to use them.
• SQL Functions: Learn about the SQL functions supported by the Snowflake emulator.
• Changelog: Find information about the Snowflake emulator’s changelog.