MinIO

Technical Preview

Overview

A client-mode connector for a curated IIoT object-storage slice of the MinIO S3-compatible API under path-style https://play.min.io (or your self-hosted host):

Catalog connector event	Entity / path	Notes
(smoke)	`GET /`	ListBuckets for the signing identity
PUT object (snapshot, CSV rollup)	`PUT /{bucket}/{key}`	SigV4 headers required
GET object	`GET /{bucket}/{key}`	SigV4 headers required
(optional) HeadObject	`HEAD /{bucket}/{key}`	Metadata without body
PUT to presigned URL	`PUT {presigned_path}`	No Authorization; switch BASE to URL origin
Bucket notifications → MQTT	—	Docs-only; configure MinIO to publish to Coreflux MQTT; future `ENABLE_SERVER` for HTTP notify

BASE_ADDRESS defaults to https://play.min.io (no trailing slash; path-style). For self-hosted MinIO use https://minio.example.com:9000 (or your TLS origin). Topics use storage/minio/<object>/<verb>.

play.min.io is MinIO’s public playground. Access keys published in MinIO SDK docs are open; treat all play data as world-readable. Prefer self-hosted for production.

Path-style vs virtual-hosted: MinIO usually expects path-style (/{bucket}/{key}), which this template uses. If virtual-hosted is enabled, set BASE_ADDRESS to https://{bucket}.your-host and use endpoints like /{key}.

Presigned PUT: set BASE_ADDRESS to the presigned URL origin only, put path+query in presigned_path, and omit SigV4 headers — the query string carries the signature. Ideal for edge devices that must not hold access keys.

Bucket notifications: MinIO can publish object events directly to MQTT (point at your Coreflux broker). That fan-out is configured on the MinIO side and is not part of this client connector. Receiving HTTP notification POSTs would need a separate ENABLE_SERVER REST_API (not packaged).

Admin API (/minio/admin/…, mc admin) is out of scope for this template — keep ops Admin calls outside the object-storage connector.

Basic Syntax

# Coreflux REST_API template — MinIO curated S3-compatible slice
# Auth: SigV4 via {value.json.authorization}, {value.json.x_amz_date},
#       {value.json.x_amz_content_sha256} — or PutPresigned (no Authorization)
# BASE_ADDRESS: https://play.min.io (path-style); swap for self-hosted

DEFINE ROUTE MinioRestApi WITH TYPE REST_API
    ADD REST_API_CONFIG
        WITH BASE_ADDRESS "https://play.min.io"
        WITH ENABLE_CLIENT "true"
        WITH USE_SSL "true"
        WITH REQUEST_TIMEOUT '60'
        WITH DEFAULT_CONTENT_TYPE "application/octet-stream"
    ADD EVENT Listbuckets
        WITH SOURCE_TOPIC "storage/minio/buckets/list"
        WITH DESTINATION_TOPIC "storage/minio/buckets/list/response"
        WITH METHOD "GET"
        WITH ENDPOINT "/"
        WITH HEADERS
            ADD "Accept" "application/xml"
            ADD "Authorization" "{value.json.authorization}"
            ADD "x-amz-date" "{value.json.x_amz_date}"
            ADD "x-amz-content-sha256" "{value.json.x_amz_content_sha256}"
    ADD EVENT Putobject
        WITH SOURCE_TOPIC "storage/minio/object/put"
        WITH DESTINATION_TOPIC "storage/minio/object/put/response"
        WITH METHOD "PUT"
        WITH ENDPOINT "/{value.json.bucket}/{value.json.key}"
        WITH HEADERS
            ADD "Accept" "application/xml"
            ADD "Content-Type" "{value.json.content_type}"
            ADD "Authorization" "{value.json.authorization}"
            ADD "x-amz-date" "{value.json.x_amz_date}"
            ADD "x-amz-content-sha256" "{value.json.x_amz_content_sha256}"
        WITH BODY "{payload}"
    ADD EVENT Getobject
        WITH SOURCE_TOPIC "storage/minio/object/get"
        WITH DESTINATION_TOPIC "storage/minio/object/get/response"
        WITH METHOD "GET"
        WITH ENDPOINT "/{value.json.bucket}/{value.json.key}"
        WITH HEADERS
            ADD "Accept" "*/*"
            ADD "Authorization" "{value.json.authorization}"
            ADD "x-amz-date" "{value.json.x_amz_date}"
            ADD "x-amz-content-sha256" "{value.json.x_amz_content_sha256}"
    ADD EVENT Headobject
        WITH SOURCE_TOPIC "storage/minio/object/head"
        WITH DESTINATION_TOPIC "storage/minio/object/head/response"
        WITH METHOD "HEAD"
        WITH ENDPOINT "/{value.json.bucket}/{value.json.key}"
        WITH HEADERS
            ADD "Authorization" "{value.json.authorization}"
            ADD "x-amz-date" "{value.json.x_amz_date}"
            ADD "x-amz-content-sha256" "{value.json.x_amz_content_sha256}"
    ADD EVENT Putpresigned
        WITH SOURCE_TOPIC "storage/minio/object/put-presigned"
        WITH DESTINATION_TOPIC "storage/minio/object/put-presigned/response"
        WITH METHOD "PUT"
        WITH ENDPOINT "{value.json.presigned_path}"
        WITH HEADERS
            ADD "Content-Type" "{value.json.content_type}"
        WITH BODY "{payload}"

Configuration

Setting	Value
Connector name	`MinioRestApi`
Type	`REST_API` (client)
BASE_ADDRESS	`https://play.min.io` (path-style default; swap for self-hosted)
Topic prefix	`storage/minio/...`
Default Content-Type	`application/octet-stream`
SigV4 region	commonly `us-east-1` (service `s3`)
Hub status	Technical preview (`WITH STATUS "beta"`)

Authentication

AWS Signature Version 4

MinIO uses the same SigV4 scheme as S3 — not Authorization: Bearer …. Sign each request with SigV4 (service s3) and pass:

MQTT JSON field	HTTP header
`authorization`	`Authorization` (`AWS4-HMAC-SHA256 Credential=…`)
`x_amz_date`	`x-amz-date`
`x_amz_content_sha256`	`x-amz-content-sha256`

Use Hub secrets for MINIO_ACCESS_KEY / MINIO_SECRET_KEY (or AWS-named equivalents) in an upstream signing helper. Never commit real keys.

Presigned URLs (recommended for edge)

Generate a time-limited PUT or GET URL with mc, the AWS CLI, or a MinIO SDK. For PutPresigned:

Point BASE_ADDRESS at the URL origin.
Put path + query into presigned_path.
Omit Authorization — do not re-sign on the broker.

MQTT topics

Event	Request topic	Response topic
ListBuckets	`storage/minio/buckets/list`	`…/response`
PutObject	`storage/minio/object/put`	`…/response`
GetObject	`storage/minio/object/get`	`…/response`
HeadObject	`storage/minio/object/head`	`…/response`
PutPresigned	`storage/minio/object/put-presigned`	`…/response`

Example payloads

ListBuckets smoke (after signing):

{
  "authorization": "AWS4-HMAC-SHA256 Credential=AKIA.../20261004/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=...",
  "x_amz_date": "20261004T040000Z",
  "x_amz_content_sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
}

PutObject CSV rollup:

{
  "bucket": "my-iiot-rollups",
  "key": "line-a/2026-10-04/rollup.csv",
  "content_type": "text/csv",
  "authorization": "AWS4-HMAC-SHA256 Credential=...",
  "x_amz_date": "20261004T040100Z",
  "x_amz_content_sha256": "<sha256 of body>",
  "payload": "ts,device,temp\n2026-10-04T04:01:00Z,sensor-01,72.5\n"
}

PutPresigned:

{
  "presigned_path": "/my-iiot-rollups/line-a/snapshot.json?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=...&X-Amz-Signature=...",
  "content_type": "application/json",
  "payload": "{\"device\":\"sensor-01\",\"temp\":72.5}"
}

References

Package status

Ready on the factory after live SigV4 smoke against https://play.min.io (ListBuckets + Put/Get/Head) recorded in TEST.md. Hub / docs status remains beta. Swap BASE_ADDRESS to your self-hosted MinIO for production.

Quick Start

Coreflux MQTT Broker

LoT Language

Coreflux HUB

VS Code - LoT Notebooks

Coreflux Portal

Using AI with Coreflux

Product Updates

Overview

Basic Syntax

Configuration

Authentication

AWS Signature Version 4

Presigned URLs (recommended for edge)

MQTT topics

Example payloads

References

Package status

​Overview

​Basic Syntax

​Configuration

​Authentication

​AWS Signature Version 4

​Presigned URLs (recommended for edge)

​MQTT topics

​Example payloads

​References

​Package status

Overview

Basic Syntax

Configuration

Authentication

AWS Signature Version 4

Presigned URLs (recommended for edge)

MQTT topics

Example payloads

References

Package status