[crabbone]

> The second problem with writing logs to stdout

Who on Earth does that? Logs are almost always written to stderr... In part to prevent other problems author is talking about (eg. mixing with the output generated by the application).

I don't understand why this has to be either or... If you store the trace output somewhere you get a log... (let's call it "un-annotated" log, since trace won't have the human-readable message part). Trace is great when examining the application interactively, but if you use the same exact tool and save the results for later you get logs, with all the same problems the author ascribes to logs.

[OJFord]

Loads of people, it drives me around the twist too (especially when there's inevitably custom parsing to separate the log messages from the output) but it happens, probably well correlated with people that use more GUI tools, not that there's anything wrong with that, just I think the more you use a CLI the more you're probably aware of this being an issue, or other lesser best practices that might make life easier like newline and tab separation.

[FridgeSeal]

I do, as does everyone at my work? Along with basically everyone I’ve ever worked with, ever?

Like, I develop cli apps, so like, what else would go to stdout that you suppose will interfere?

[crabbone]

Nothing will go to stdout! Nothing is the best thing you can have when it comes to program output. Easiest validation! This is also how all Unix commands work -- they don't write to stdout unless you tell them to. But, if there's nothing extraordinary happening during the program execution -- nothing is written.

But why would you write your own logs instead of using something built into your language's library? I believe Python's logging module writes to stderr by default. Go's log package always goes to stderr.

But... today I've learned that console.log() in NodeJS writes to stdout... well, I've lots another tiny bit of faith in humanity.

[FridgeSeal]

> This is also how all Unix commands work -- they don't write to stdout unless you tell them to

Ok? But as per my other comment, I’m not writing CLI apps, it’s mostly services and I have supporting services which harvest the logs from each containers stdout.

> But why would you write your own logs instead of using something built into your language's library?

I’m not writing my own logging setup? I am using the provided tools?? Every language logging library I’ve ever used writes to stdout?

Structlog in Python, nodejs obvs, all the Rust logging libraries I’ve ever used, I know you can configure Java/scala 3 million different ways (hello yes log4j lol), but all the Spark stuff I’ve written has logged to stdout.

[FridgeSeal]

Can’t edit this now, but this is supposed to say “I don’t develop cli apps”

[dalyons]

Being doing it for decade+, ever since the 12 factor app concept became popular. It’s way more common imho for web apps than stderr logging.