Now someone should open a Jira ticket, refine the task, estimate it, define its priority, push it to the backlog and maybe the next sprint (if it is important enough), someone will be assigned, checking all the DoD and DoR boxes, submit a PR, getting it approved and then it will be fixed.
Exactly-once semantics is virtually impossible to achieve, there is a lot of literature all over the internet, but an easy example could be the following.
Imagine a client sending messages to RabbitMQ with some retry policy if it doesn't receive the ACK from the broker. If the client sends the message and it doesn't receive the ACK in the terms it has been defined (maybe a timeout of 30s), it will retry to send the message, as the consumer assumes that the message hasn't been received by the brokers, but it could be that the ACK back to the client is the one that failed to be sent to the client. The brokers actually saved the message, and they stored it, but the client doesn't know, so it retries the message.
If you don't have some control over the messages, this retried message is _new_ to RabbitMQ, so it will store it and send back the ACK. Maybe this time it is successful and no other retries are made.
With this scenario, the brokers would have received the same message twice. By adding this kind of control (Kafka does more or less the same by discarding messages with already processed IDs when configured as exactly-once) you can try to avoid duplicates. Of course it is limited by memory and it is not in fact exactly-once semantics, so they are calling it now _effectively exactly-once semantics_, as it is more precise.
Yep, I am writing the posts in HTML. The reason to avoid Markdown (which I love) and other things is to avoid any kind of building tools. I tried to install Gatsby on a Windows machine and I had several errors. I wanted to remove any dependency on external software. I wanted it to be modifiable with just a text editor and nothing else.
Regarding the use of <span> is because the <p> tag with the chosen CSS leaves too much space after <h*> tags, while <span> doesn't, and as I wanted to just use HTML tags and not create my own version of the CSS, I found <span> the easiest way to achieve that.
I did almost the same last weekend. I wanted to start a blog[1] but all options seemed too much for a simple purpose that is a blog. After researching about VuePress, Sapper, Next.js, Gatsby and so on, I finally decided that it wouldn't have any kind of JavaScript. I was tempted to create yet another static site generator, but I am sticking to the old HTML + CSS duo (and, regarding CSS, classless CSS) for my blog. Yes, it has some downsides, but hey, it only needs a text editor and internet connection and the blog is blazingly fast.