1. Choosing a Communication Protocol Ops systems are better suited to HTTP than to gRPC. More ops and R&D engineers are familiar with HTTP than with other protocols. Once you know the HTTP protocol, learning a RESTful-style HTTP API is quick. Being familiar to more people and easier to learn means better communication and lower handover cost, because they share more common domain background.

Recently I was responsible for developing a backend-heavy application. The data flow in this application is complex, and the processing logic has piled up in a redundant mess. The project’s tech stack is Django + Vuejs. The frontend is bundled with Webpack, managed in modules, and mainly displays data. The backend involves many modules, many processing rules, and many data tables, so every time I had to modify an earlier feature I spent a lot of time reviewing the code.

As requirements are gradually confirmed, the system’s DB model is gradually confirmed as well. Sometimes you use a tool like MySQL Workbench to draw an E-R diagram and then generate MySQL database tables, and at that point you need to reverse-generate Django Models; other times you write the Django Models directly, but then you need to look at the E-R diagram.

1. Terminology xpath: There are two approaches, the exact path and the approximate path. Exact path: body>div[0]>div[3]>ul>li[5]>a[0], walking up from the clicked element all the way to the root node and recording every node along the way. Approximate path: body>div.header>div.nav>a[23], which on top of the former omits from the upward path any node that is not on the whitelist.

A quick word on the project requirements: the team needed to publish documentation externally. The documents are written in Markdown and need to be published as HTML. At first we used an Nginx + Jekyll solution. As the documentation grew, the document system developed a strong need for search. I