The Transform Service handles the essential transforms, such as Microsoft Office documents, images, and PDFs. These include PNG for thumbnails, PDF and JPEG for downloads and previews.
Components of the Transform Service
- Content Repository (ACS): This is the repository where documents and other content resides. The repository produces and consumes events destined for the message broker (such as ActiveMQ or Amazon MQ). It also reads and writes documents to the shared file store.
- ActiveMQ: This is the message broker (either a self-managed ActiveMQ instance or Amazon MQ), where the repository and the Transform Router send image transform requests and responses. These JSON-based messages are then passed to the Transform Router.
- Transform Router: The Transform Router allows simple (single-step) and pipeline (multi-step) transforms that are passed to the Transform Engines. The Transform Router (and the Transform Engines) run as independently scalable Docker containers.
- Transform Engines: The Transform Engines transform files referenced by
the repository and retrieved from the shared file store. Here are some example
transformations for each Transform Engine (this is not an exhaustive list):
- LibreOffice (e.g. docx to pdf)
- ImageMagick (e.g. resize)
- Alfresco PDF Renderer (e.g. pdf to png)
- Tika (e.g. docx to plain text)
- Misc. (not included in diagram)
- Shared File Store: This is used as temporary storage for the original source file (stored by the repository), intermediate files for multi-step transforms, and the final transformed target file. The target file is retrieved by the repository after it's been processed by one or more of the Transform Engines.
The following diagram shows a simple representation of the Transform Service components:
This shows an example implementation of how you can deploy into AWS, using a number of managed services:
- Amazon EKS - Elastic Container Service for Kubernetes
- Amazon MQ - Managed message broker service for Apache ActiveMQ
- Amazon EFS - Amazon Elastic File System
You can replace the AWS services (EKS, MQ, and EFS) with a self-managed Kubernetes cluster, ActiveMQ (configured with failover), and a shared file store, such as NFS.
The advantage of using Docker containers is that they provide a consistent environment for development and production. They allow applications to run using microservice architecture. This means you can upgrade an individual service with limited impact on other services.
Some of the Docker images that are used by the Transform Service are uploaded to a private registry, Quay.io. Enterprise customers can contact Alfresco Support to request Quay.io account credentials to pull the private (Enterprise-only) Docker images:
The other images are available in DockerHub:
For information about deploying and configuring the Transform Service, see Deploying Transform Service.
See Transform Service vs. Local and Legacy Transforms to review changes in Alfresco Content Services 6.2 and Transform Service 1.1.