Cut OSS Storage Costs with Real‑Time Image Processing Using Function Compute

Solution Overview

Most customers store large volumes of unstructured media (images, video, audio) in Alibaba Cloud Object Storage Service (OSS). Different devices require different image formats and resolutions, which leads to many derivative files and high storage costs. OSS Object FC enables storing only the original image in OSS and generating the required version in real time based on request parameters, eliminating the need to keep all derivative files.

Typical Scenarios

Scenario 1: Only the original image is stored in OSS. The client includes processing parameters (e.g., format, size, watermark) in the request URL; the returned image is already transformed according to those parameters.

Scenario 2: A single format image is stored in OSS. Regardless of the format requested in the URL, the system returns the image in the requested format after on‑demand conversion.

Advantages

Only the original image needs to be retained, significantly reducing OSS storage costs.

Business logic such as watermarking, beautification, cropping, or frame extraction can be applied at request time without custom development on the OSS side, giving customers full control and strong extensibility.

Key Terminology

OPAP (Object Process Access Point): An extension of the standard Access Point (AP). A GetObject request to an OPAP triggers a Function Compute (FC) function; other request types fall back to the bound AP.

AP (Access Point): A dedicated OSS domain name with independent permission control, allowing fine‑grained access for different business units.

Product Components

VPC (Virtual Private Cloud): Isolated private network for deploying cloud resources such as ECS, SLB, RDS, etc.

Function Compute (FC): Event‑driven, fully managed serverless compute service. Users upload code or container images; the platform handles scaling, logging, monitoring, and alerts.

CDN (Content Delivery Network): Distributed edge servers cache origin resources to reduce latency and origin load.

OSS (Object Storage Service): Highly durable, low‑cost cloud storage with 99.9999999999% data durability and 99.995% availability.

CADT (Cloud Architect Design Tools): Self‑service tool that provides templates and drag‑and‑drop design for rapid deployment of cloud architectures.

Prerequisites

Alibaba Cloud account with real‑name verification completed.

Pay‑as‑you‑go resources purchased; account balance > ¥200 to cover hourly charges.

Git environment ready to clone the sample repository.

Domain name that has passed ICP filing.

Step‑by‑Step Implementation

Environment preparation

Clone sample code

git clone https://github.com/aliyun-samples/oss-object-fc-demo.git

Configure OSS

Create an Access Point (AP).

Create an Object FC Access Point (OPAP) linked to the AP.

Grant required RAM permissions to the OPAP.

Upload sample images to the bucket.

Configure Function Compute

Log in to the FC console.

Deploy the image‑processing function code (the function parses URL parameters and applies the requested transformations).

Update the OSS SDK and pyOpenSSL dependencies in the function package.

Configure CDN

Add a CDN domain that points to the OPAP as the origin.

Configure CNAME resolution for the domain to the CDN endpoint.

Set cache‑behavior and header forwarding rules as needed.

Validate Scenarios

Test format conversion by requesting https://cdn.example.com/image.jpg?format=png.

Test real‑time resizing with parameters such as w=200&h=150.

Explore additional use cases (watermark, cropping, frame extraction).

Resource cleanup – release VPC, FC, CDN, and OSS resources with a single click after testing.

Full Request Flow

User requests an image via a CDN URL.

If the CDN cache misses, the request is forwarded to the OPAP.

The OPAP triggers the Function Compute function; the function extracts processing parameters from the URL and performs the image transformation.

The processed image is returned to the AP, which forwards it to OSS.

OSS serves the image back to the CDN, which delivers it to the client.

All configurations—CDN origin settings, OPAP creation, AP creation, and function code—are performed through the Alibaba Cloud console.