Any code or blog written by Adam is worth spending some time on.
It will be interesting to see how the tasks framework develops and expands. I am sad to see the great Django-Q2 lumped in with the awful Celery though.
I'm of the opinion that django task apps should only support a single backend. For example, django-rq for redis only. There's too many differences in backends to make a good app that can handle multiple. That said, I've only used celery in production before, and I'm willing to change my mind.
It's okay till it's not. Everyone I know who had Celery in production was looking for a substitution (custom or third-party) on a regular basis. Too many moving pieces and nuances (config × logic × backend), too many unresolved problems deep in its core (we've seen some ghosts you can't debug), too much of a codebase to understand or hack. At some point we were able to stabilize it (a bunch of magic tricks and patches) and froze every related piece; it worked well under pressure (thanks, RabbitMQ).
Celery is great and awful at the same time. In particular, because it is many Python folks' first introduction to distributed task processing and all the things that can go wrong with it. Not to mention, debugging can be a nightmare. Some examples:
- your function arguments aren't serializable
- your side effects (e.g. database writes) aren't idempotent
- discovering what backpressure is and that you need it
- losing queued tasks during deployment / non-compatible code changes
There's also some stuff particular to celery's runtime model that makes it incredibly prone to memory leaks and other fun stuff.
> your side effects (e.g. database writes) aren't idempotent
What does idempotent mean in this context, or did you mean atomic/rollback on error?
I'm confused because how could a database write be idempotent in Django? Maybe if it introduced a version on each entity and used that for crdt on writes? But that'd be a significant performance impact, as it couldn't just be a single write anymore, instead they'd have to do it via multiple round trips
Because it’s a seducer. It does what you need to do and you two are happy together. So you shower more tasks on Celery and it becomes cold and non-responsive at random times.
And debugging is a pain in the ass. Most places I’ve been that have it, I’ve tried to sell them on adding Flower to give better insight and everyone thinks that’s a very good idea but there isn’t time because we need to debug these inscrutable Celery issues.
Template partials look good, which is one of the key reasons frameworks like React are as good and popular as they are, because you can reuse small segments of code.
I do a check for `request.htmx` in my views and conditionally return a template partial as needed. This reduced my need for one-off view functions that were only returning partials for htmx. Works pretty well from my experience.
It's just syntactic sugar, making life a bit easier for HTMX users (cf. "htmx was the main motivation for this feature").
I'm using Unpoly and I just render the whole page and let Unpoly swap the content according to the target selectors, so no need for this. Not much difference in perf if you dont generate gigantic pages with heavy header/footer.
Partialdef inline is the real win. Lets you define parts of a page without needing to place them in another file. Reduces the mental overhead of imagining how the inclusion will look because it’s already there.
The use case is mainly driven by htmx where you will have lots of these partials and the view code renders them as individual responses.
you're kinda right, {% partial ... %} vs {% include ... %} is not a big difference, but my mind was vaguely thinking that "includes" have often been seen as large templates, whereas partial have been after the component era with the idea of making small blocks. (my 2 cents)
Yeah, but I was doing the same thing 10 years ago with include mixed with extends and blocks. I can just include a file inside a template or render it directly.
After the move away from the use of 'master' in programming parlance (understandably IMHO), as a Brit I'm always slightly surprised to see 'nonce' still being acceptable.
It makes me sad when a secondary meaning, which does not even overcome the main meaning in usage, becomes an obstacle for the normal use of a word. It's like seeing a rainbow as a sexualized symbol not fit for children, because it also happens to be used by LGBTQ+ community. (BTW, since you're a Brit: did people stop using the word "fag" to refer to a cigarette?)
I mean, it is sad. But unfortunately that is what happened with "master", "slave", "whitelist", and "blacklist". No reasonable person construed these as offensive or having any implications about the wider world. But there are people in our profession who are determined to take offense where none is given, and unfortunately they got their way.
Well, "slave" has a pretty direct main meaning of an oppressed person doing forced labor. The word "master" is much milder in this regard (compare "master's degree" and "slave's degree"). The word "nonce" in normal usage seems even more removed from any pejorative secondary meanings.
That didn't stop people from throwing a fit over master-slave terminology in software (having nothing to do with slavery), going so far as to rename long-standing development branch names, as well as put significant effort into removing such terms from the code itself and any documentation.
Also, good to see first class support for Tasks, among a lot of other niceties!
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