Show the current span in the console.

[najamelan]

By default, tracing-subscriber shows span information in log events. I am using tracing in a library, so I'm trying to figure out how best to annotate things. I call user supplied code, so I don't necessarily get to put structured data directly on the log events, so a span seemed to be a good way to add information. However, if it doesn't get shown that doesn't work. I personally prefer putting the span information after the message, as it seems more optional.

I suppose fixing #13 would also fix this in a more general but less default way.

[lilyball]

I just tried switching over to tracing-wasm and was very surprised to see that the fields I've added to my spans aren't showing up. That removes most of the utility of my logging. Even without supporting tracing-subscriber's FormatEvent, this crate should at least include span names and fields.

[jquesada2016]

Any update on this? Logging without span information is generally a big problem, as all context to the events are lost.

[Madoshakalaka]

just for reference
for example this is how tracing_journald handles spans:

journalctl -u my_service -o verbose

Thu 2025-02-27 13:19:36.619089 JST [s=efcb3034391b4c4eb855cbb8040955e0;i=ba2aad9;b=893b89e3c2a9473cb3288102206648cc;m=5b7bc41a39e;t=62f17ff71638a;x=32bf09b0fbf800da]
    _SYSTEMD_UNIT=my_crate_name.service
    TARGET=my_crate_name
    CODE_FILE=my_crade_name/src/main.rs
    SPAN_NAME=proxy_handler
    SPAN_TARGET=my_crate_name
    SPAN_CODE_FILE=server/src/main.rs
    SPAN_CODE_LINE=573
    F_HOST=Host(11.22.333.44:8080)
    F_PATH="health"
    CODE_LINE=611
    MESSAGE=Proxying request to: http://127.0.0.1:8500/health
    _PID=3537799
    _SYSTEMD_INVOCATION_ID=a612986ca76342c99c847f20b67617b3
    F_REQ=Request { method: GET, uri: /proxy/health, version: HTTP/1.1, headers: {"host": "11.22.333.44:8080", "user-agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like G>
    _SOURCE_REALTIME_TIMESTAMP=1740629976619089

(some lines omitted)

In this case the span is generated by an instrumented
async function with host, path, req arguments and the message is emitted by debug!("proxying request to ...")

But I don't know if you can attach fields to messages in javascript..?

[jquesada2016]

Just in case anybody needs an alternative, I created tracing-subscriber-wasm

[Madoshakalaka]

Just in case anybody needs an alternative, I created tracing-subscriber-wasm

thanks, I just checked it out but it doesn't seem to add any span information either?

[jquesada2016]

thanks, I just checked it out but it doesn't seem to add any span information either?

Huh, are you sure you're setting up tracing_subscriber correctly? It absolutely includes span information for all of us. Checkout the README for the project I linked. It shows how to configure tracing_subscriber to emit spans

[jquesada2016]

To clarify, since tracing-subscriber-wasm uses a Writer implementation, rather than being a totally different subscriber, it tracing-subscriber can display it, so can tracigin-subscriber-wasm. You need to opt-in to viewing span events if that's what you're looking for. Otherwise, you can customize the message format when setting up tracing-subscriber