Introduction
Getting certified copies of official documents should be a simple straightforward task. Currently, this is not the case. It is somewhat tedious, time-consuming, and requires an unnecessary amount of energy for all parties involved. However, this can be automated into a simple online process. I introduce you to Certify-d.
Disclaimer: I provide the following only as a way to showcase my skills, learn, and test the feasibility of such a complex system. Do not use this software in critical situations or projects.
What is Certify-d?
The purpose of Certify-d is to generate certified copies — ie. documents regarded as true copies of the original. Useful in cases where the original is to be kept safe by the owner, the copies require an official signature from a legally authorised person.
Main features:
- upload original documents, e.g. identity documents and qualifications;
- generate certified copies, with a legally authorised signature/stamp; and
- share certified copies w/ relevant parties.
The application should only produce certified copies. Verifying that a document is genuine — that is not forged — is out of scope and falls not in our responsibility.
In order of importance and priority, the following are our quality goals:
- functional correctness: provide a high degree of accurate result for tasks;
- time behaviour: system should handle tasks and deliver in well reasonable time;
- interoperability: provide a simple API to allow for different and new clients to connect.
System Scope and Context
At the highest level of abstraction, we differentiate the business context and technical context of our system.
As for our business context, we identify:
- Person/Actors: the customer, staff, and commissioners (companies);
- The System: the system at the highest level of abstraction;
- External Systems: Payment provider, Auth provider, Email service, and SMS service.
As for our technical context, within the “Certify-d System” boundary, there exist multiple containers (deployable units of work). The containers all use HTTP requests to interface and communicate.
System Container
The Certify-d system will consist of multiple APIs running as containerised servers communicating with other services and front-end clients.
Building the system using Go(lang) is a clear choice given the following benefits:
- development team has good experience with the language and eco-system,
- compiles our services to relatively small statically linked native binaries, and
- good support for concurrent programming.
We look at functional, unit, and integration tests as providing an acceptable level of functional correctness.
Regarding time behavoiur as a quality goal, the process of generating certified copies can be a long-running task. The implementation of an event-driven system with a persistence log/queue allows us to achieve an acceptable time and guarantee.
Use of the OpenAPI Specification (OAS) allows us to meet our Interoperability quality goal by providing clients a standardised interface to interact with our system through HTTP APIs. Further allowing the simplification of our API Documentation efforts, and code generation of clients.
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