tokio-rs/tracing

Application-level tracing for Rust.

Christian Schilling

@christian-schilling

    tracing_log::LogTracer::init().expect("can't init LogTracer");
    let subscriber = tracing_subscriber::fmt::Subscriber::default();
    tracing::subscriber::set_global_default(subscriber).expect("failed to set");

    log::info!("A");
    log::debug!("B");

Prints A but not B. I don't understand why. There are no filters so it should print everything. Or what am I missing?

Also I can't get it to output anything originating from the other crates (I know my app produces lots of log events coming from tokio_core)

Christian Schilling

@christian-schilling

Also, assuming I can get this working at some point: I have been using rs_tracing to produce output compatible with about://tracing in chrome. Is someone working on this for tracing as well? If not I will. Would it make sense to put is into tracing_subscriber or make a new crate?

David Barsky

@davidbarsky

heya @initcrash we’re way more active in discord, but the the default settings filter at info, i believe

Christian Schilling

@christian-schilling

The invite link above seems to be expired

David Barsky

@davidbarsky

https://discord.gg/Nf2GP3V here’s an unlimited one

Christian Schilling

@christian-schilling

thanks :)

David Barsky

@davidbarsky

but the chrome tracing one—maybe a separate crate would be best, but building on the interface in tracing-subscriber

(sorry, gitter is terrible on iOS 13, and i’m not at work yet.)

@initcrash responded to your question in tracing-users on discord :)

matrixbot

@matrixbot

an_zhuo Hi, I'm using tracing with async_std and noticed when I process a stream with for_each_concurrent that it creates multiple nested spans randomly

an_zhuo Idk if I'm just doing something wrong or if that's a bug. Within for_each_concurrent I am calling task::spawn and then creating a span inside the async block

an_zhuo It's only one span, and the block is pretty short

an_zhuo But the log ends up with nested spans like span_name:{something}:span_name:{somethingelse}:span_name:{different thing}

an_zhuo Any idea what could be going on?

matrixbot

@matrixbot

Ralith > <@anzhuo:matrix.org> Any idea what could be going on?

yeah, for async code you need to use tracing-futures' Instrument extension trait

Ralith the RAII guards have no way to know they're in an async context, so they can't properly enter/exit the span on every poll, leading to the behavior you observed

an_zhuo > <@ralith:ralith.com> the RAII guards have no way to know they're in an async context, so they can't properly enter/exit the span on every poll, leading to the behavior you observed

Thank you so much! I will try that.

matrixbot

@matrixbot

Ralith np, good luck!

Johannes Lundberg

@johalun

Hi! How can I filter on one or more targets?

matrixbot

@matrixbot

Ralith the envlogger subscriber works the same way the envlogger crate does

Felipe Lessa

@meteficha

Hello, all! What's the best way of initializing tracing_subscriber::fmt inside tests? Should I simply try to initialize it while ignoring failures on every test? E.g.:

  #[test]
  fn foo() {
    let _ = tracing_subscriber::fmt::try_init();
    ...
  }

David Barsky

@davidbarsky

https://docs.rs/tracing/0.1.11/tracing/subscriber/fn.with_default.html is what i do

(we’re also not active here. we’re on discord: https://discord.gg/ArWJn2F)

Felipe Lessa

@meteficha

Cool, thanks, @davidbarsky (:

Luis Wirth

@LU15W1R7H

Hi, I've got a question:
Is there an existing way to write the output of tracing to a file. Or can I integrate tracing with the fern crate, which already provides such functionality?

matrixbot

@matrixbot

Ralith https://github.com/tokio-rs/tracing/tree/master/tracing-appender

Ralith discord's more active

Luis Wirth

@LU15W1R7H

thanks x2

sarvi

@sarvi

I am building a LD_Preload Library in RUST ad want to enable tracing for LD_PRELOAD Library. I had added tracing package and turned "log-always" feature in Cargo.toml and have istrumented the code with with both event!(Level::INFO, "linkat(...)"); and a println but dont the event only the println

not the event

In this case because it is a LD_preload I dont have a way to initializer the tracing subscriber

sarvi

@sarvi

I could do it in the library consttructor. But it is recommended not the create/initalize subscribers in a library. May be this is an exception case. But the LD_PRELOAD could apply to a rust executable program in future

wagnerf42

@wagnerf42

hi, i'm writing a toy Subscriber to discover the tracing crate. i don't get why the current_span method is never called. i thought by default nested spans would ask the subscriber for setting parents

the new_span does'nt give writable access to the parent so it's not there to be set

hum, i'll repost on discord

Edward Middleton

@Eonprog_twitter

Are there any good resources on how people are using tracing in development? I am working on some code that involves video decompression, so a lot of bit manipulation and it has been useful in debugging parts of the code but I am finding I go into a lot of detail working through a particular path, but then want to hide most of it when moving onto the next bit, its often not mapping in ways that can be easily filtered.

mehmetcodes

@mehmetcodes

Does the tracing library support windows?

I've been trying basic examples and nothing wants to print

mehmetcodes

@mehmetcodes

I am thinking maybe this has something to do with it being in a tokio main async function?

nolan

@nolan:thewordnerd.info

[m]

Hey folks, are there any tracing subscribers which, when a program ends, display the min/max/average timing of spans? I'm trying to identify bottlenecks, and am wondering if there's an easy way to get a textual report that I can easily sort?

I'm guessing tracing-fmt is more like a logger, but what I'm looking for is some sort of list of spans and their timings. Maybe it does that as well?

Lukáš Hozda [magnusi]

@luciusmagn

hi, we are currently trying to switch from slog to tracing, and we are facing an issue with log levels

we used to have a workflow that just compiling regardless of whether release or debug, we had all log levels compiled in (max_level_trace, release_max_level_trace)

we had it under a feature

and when creating a public build, we used --no-default-features to make it only compile in info and higher

but in tracing, from what I saw, the order of those features is reversed

so if I have max_level_trace and max_level_info, we'll get only info

iensu

@iensu:matrix.org

[m]

Hi! I want to send my tracing logs to Azure Application Insights and wonder what the idiomatic way of achieving this is? Implement a Layer?

Yuri6037

@Yuri6037

Hi, I have an issue using tracing in my application: I can't access my tracing subscriber once it's set: downcast_ref in global get_default closure always returns None. Is there any reason why?

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