example appender-multifile.rs help

[ximengyi]

i am learning tracing i want to use appender-multifile.rs in my project so
i copy code

  let debug_file = rolling::minutely("./logs", "debug");
    // Log warnings and errors to a separate file. Since we expect these events
    // to occur less frequently, roll that file on a daily basis instead.
    let warn_file = rolling::daily("./logs", "warnings").with_max_level(tracing::Level::WARN);
    let all_files = debug_file.and(warn_file);

    tracing_subscriber::fmt()
        .with_writer(all_files)
        .with_ansi(false)
        .with_max_level(tracing::Level::TRACE)
        .init();

but it doesn't work , The compiler prompts me follow

the method `with_max_level` exists for struct `tracing_appender::rolling::RollingFileAppender`, but its trait bounds were not satisfied

method cannot be called on `tracing_appender::rolling::RollingFileAppender` due to unsatisfied trait bounds

the method `and` exists for struct `tracing_appender::rolling::RollingFileAppender`, but its trait bounds were not satisfied

can anyone give me a help ?

[davidbarsky]

What branch are you using as an example? What dependencies have you included in your Cargo.toml? Additionally, can you paste the full error you're getting when you're compiling?

[ximengyi]

i use branch 0.3.8 and this is my cargo.toml

[package]
name = "trace-example"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
axum = { version = "0.4" }
tokio = { version = "1.0", features = ["full"] }
tracing = "0.1"
tracing-subscriber = "0.3.8"
tracing-appender = "0.2"
tower-http = { version = "0.2", features = ["trace"] }
serde = { version = "1.*", features = ["derive"] }
serde_json = "1.0.*"

and the full error is :

error[E0599]: the method `with_max_level` exists for struct `RollingFileAppender`, but its trait bounds were not satisfied
  --> src/main.rs:17:61
   |
17 |     let warn_file = rolling::daily("/opt/logs", "warnings").with_max_level(Level::WARN);
   |                                                             ^^^^^^^^^^^^^^ method cannot be called on `RollingFileAppender` due to unsatisfied trait bounds
   |
  ::: /home/meng/.cargo/registry/src/github.com-df7c3c540f42cdbd/tracing-appender-0.2.0/src/rolling.rs:55:1
   |
55 | pub struct RollingFileAppender {
   | ------------------------------
   | |
   | doesn't satisfy `RollingFileAppender: MakeWriter<'_>`
   | doesn't satisfy `RollingFileAppender: MakeWriterExt`
   |
   = note: the following trait bounds were not satisfied:
           `RollingFileAppender: MakeWriter<'_>`
           which is required by `RollingFileAppender: MakeWriterExt`
           `&RollingFileAppender: MakeWriter<'_>`
           which is required by `&RollingFileAppender: MakeWriterExt`
           `&mut RollingFileAppender: MakeWriter<'_>`
           which is required by `&mut RollingFileAppender: MakeWriterExt`

error[E0599]: the method `and` exists for struct `RollingFileAppender`, but its trait bounds were not satisfied
  --> src/main.rs:19:32
   |
19 |     let all_files = debug_file.and(warn_file);
   |                                ^^^ method cannot be called on `RollingFileAppender` due to unsatisfied trait bounds
   |
  ::: /home/meng/.cargo/registry/src/github.com-df7c3c540f42cdbd/tracing-appender-0.2.0/src/rolling.rs:55:1
   |
55 | pub struct RollingFileAppender {
   | ------------------------------
   | |
   | doesn't satisfy `RollingFileAppender: MakeWriter<'_>`
   | doesn't satisfy `RollingFileAppender: MakeWriterExt`
   |
   = note: the following trait bounds were not satisfied:
           `RollingFileAppender: MakeWriter<'_>`
           which is required by `RollingFileAppender: MakeWriterExt`
           `&RollingFileAppender: MakeWriter<'_>`
           which is required by `&RollingFileAppender: MakeWriterExt`
           `&mut RollingFileAppender: MakeWriter<'_>`
           which is required by `&mut RollingFileAppender: MakeWriterExt`

warning: unused import: `tracing_subscriber::fmt::writer::MakeWriterExt`
 --> src/main.rs:5:5
  |
5 | use tracing_subscriber::fmt::writer::MakeWriterExt;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

For more information about this error, try `rustc --explain E0599`.
warning: `trace-example` (bin "trace-example") generated 1 warning
error: could not compile `trace-example` due to 2 previous errors; 1 warning emitted

[ximengyi]

Finally I solved the problem in another way

    let info_appender =rolling::daily("/opt/logs", "info");
    let (info_appender, _info_guard) = tracing_appender::non_blocking(info_appender);

    let warn_appender = rolling::daily("/opt/logs", "warn");
    let (warn_appender, _warn_guard) = tracing_appender::non_blocking(warn_appender);
    //warn_appender.is_lossy(false); //

    // let files = info_appender
    //     .with_min_level(Level::TRACE)
    //     .or_else(warn_appender.with_max_level(Level::WARN));
    

        let stdout = std::io::stdout.with_max_level(tracing::Level::TRACE);
        let files =stdout.and(info_appender.with_min_level(Level::INFO)).and(warn_appender.with_max_level(Level::WARN));
    

    tracing_subscriber::fmt()
        .with_writer(files)
        .with_ansi(true)
        .with_max_level(Level::TRACE)
        .init();

This will not compile and report an error, and it works.
i think the example/appender-multifile.rs maybe have some bugs

[ofofofofo]

I had the same problem.
It turned out the tracing-appender on crates.io is 4 month old before #1760 got merged.
Could you make a new tracing-appender release.

[hawkw]

@ofofofofo is correct, the issue is that the example depends on API changes that hadn't been released yet --- sorry about that, I forgot to publish a new version after merging #1760. I just published tracing-appender v0.2.1, so the example code should work now!