A MicroPython client for MinIO

TL, DR

MicroPython is a fantastic framework to write code for micro controllers. I just created a very simple library to enable those devices uploading files into a MinIO object storage.

MinIO object storage

I already wrote a couple of blog posts about MinIO (you can check them here), a great self-hosted object storage software. There are already Software Development Kits for many languages, but there was no official support for small electronic devices, such an ESP32. Until now!

MicroPython

MicroPython is a lean and efficient implementation of the Python 3 programming language that includes a small subset of the Python standard library and is optimized to run on micro controllers and in constrained environments.

Setup guide

Tools

• Electronic board which supports MicroPython (see a list here)
• IDE which supports MicroPython (for instance, Thonny)
• Code from my GitHub repository

Procedure

Copy __init__.py

Create a uminio folder in the /lib directory of your MicroPython device and copy the __init__.py file into it.

MinIO Credentials & Configuration

Import the MinioClient class in your MicroPython script and configure it with your MinIO server details. You can do this by setting the following variables in your script:

from uminio import MinioClient
# --- MinIO Client Configuration ---
MINIO_ENDPOINT = "192.168.1.100:9000"  # Your MinIO server IP address and port
MINIO_ACCESS_KEY = "YOUR_ACCESS_KEY"      # Your MinIO access key
MINIO_SECRET_KEY = "YOUR_SECRET_KEY"      # Your MinIO secret key
MINIO_REGION = "eu-east-1"                # The region for your MinIO server
MINIO_USE_HTTPS = False               # Set to True if your MinIO server uses HTTPS

mc = MinioClient(
    endpoint=MINIO_ENDPOINT,
    access_key=MINIO_ACCESS_KEY,
    secret_key=MINIO_SECRET_KEY,
    region=MINIO_REGION,
    use_https=MINIO_USE_HTTPS,
)

Important Security Note: Hardcoding credentials directly into the script is generally not recommended for production environments. Consider alternative methods for managing secrets on your device if security is a major concern.

IAM Permissions

Ensure the MinIO user associated with the MINIO_ACCESS_KEY and MINIO_SECRET_KEY has the necessary permissions to put objects into the specified bucket.

Usage Example

Here’s how to use uminio to upload a local file from your MicroPython device to MinIO:

import network
import time
from uminio import MinioClient
# --- MinIO Client Configuration ---
MINIO_ENDPOINT = "192.168.1.100:9000"  # Your MinIO server IP address and port
MINIO_ACCESS_KEY = "YOUR_ACCESS_KEY"      # Your MinIO access key
MINIO_SECRET_KEY = "YOUR_SECRET_KEY"      # Your MinIO secret key
MINIO_REGION = "eu-east-1"                # The region for your MinIO server
MINIO_USE_HTTPS = False               # Set to True if your MinIO server uses HTTPS

mc = MinioClient(
    endpoint=MINIO_ENDPOINT,
    access_key=MINIO_ACCESS_KEY,
    secret_key=MINIO_SECRET_KEY,
    region=MINIO_REGION,
    use_https=MINIO_USE_HTTPS,
)
# --- Network Configuration (Example for ESP32/ESP8266) ---
WIFI_SSID = "YOUR_WIFI_SSID"
WIFI_PASSWORD = "YOUR_WIFI_PASSWORD"

def connect_wifi():
    sta_if = network.WLAN(network.STA_IF) #
    if not sta_if.isconnected():
        print("Connecting to WiFi...")
        sta_if.active(True)
        sta_if.connect(WIFI_SSID, WIFI_PASSWORD)
        while not sta_if.isconnected():
            time.sleep(1)
    print("Network Config:", sta_if.ifconfig())

# --- Main Application ---
def main():
    # 1. Connect to WiFi
    connect_wifi()

    # 2. Synchronize time (critical for MinIO authentication)
    mc.sync_time() #

    # 3. Create a dummy file to upload (or use an existing file)
    local_file_to_upload = "data.txt"
    bucket_name = "my_bucket" # Ensure this bucket exists in MinIO
    s3_object_name = "my_device_data/data.txt" # Desired path and name in S3
    content_type = "text/plain" #

    try:
        with open(local_file_to_upload, "w") as f:
            f.write("Hello from MicroPython!\n")
            f.write(f"Timestamp: {time.time()}\n")
        print(f"Created dummy file: {local_file_to_upload}")
    except OSError as e:
        print(f"Error creating file: {e}")
        return

    # 4. Upload the file
    print(f"Attempting to upload '{local_file_to_upload}' to MinIO bucket '{bucket_name}' as '{s3_object_name}'...")
    if mc.upload_file(local_file_to_upload, bucket_name, s3_object_name, content_type): #
        print("Upload successful!")
    else:
        print("Upload failed.")

if __name__ == "__main__":
    main()

Related links

• MicroPython website link
• MinIO Software Development Kits link
• uminio GitHub repo link
• Other MinIO posts on RDS link

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