rmesg

Rust中的'dmesg'实现

作为一个crate: https://crates.io/crates/rmesg

作为一个命令行实用工具

获取最新版本二进制文件

wget https://github.com/archisgore/rmesg/releases/latest/download/rmesg
chmod a+x ./rmesg
# Optionally move to a stable location
mv ./rmesg /usr/local/bin

Cargo安装

cargo install rmesg

用法

rmesg: A 'dmesg' port onto Rust 1.0.0
Archis Gore <me@archisgore.com>
Reads (and prints) the kernel log buffer. Does not support all dmesg options (yet).

USAGE:
    rmesg [FLAGS] [OPTIONS]

FLAGS:
    -c               Clear ring buffer after printing (only when using klogctl)
    -f               When specified, follows logs (like tail -f)
    -h, --help       Prints help information
    -r               Print raw data as it came from the source backend.
    -V, --version    Prints version information

OPTIONS:
    -b <backend>        Select backend from where to read the logs. klog is the syslog/klogctl system call through libc.
                        kmsg is the /dev/kmsg file. [possible values: klogctl, devkmsg]

作为一个crate

这个crate的真实价值在于从Rust程序中对内核缓冲区进行程序访问，允许进行程序化的dmesg。

完整的API可以在使用sync/async版本的API的main.rs文件中找到，包括单次和迭代。

依赖于rmesg crate

在Cargo.toml中包含它

[dependencies]
rmesg = "1.0.0"

支持两个特性

• async - 提供异步Stream API
• sync - 提供同步Iterator API

单次读取缓冲区（非阻塞）

注意：单次读取是sync或async的相同接口

    use rmesg;

    // Read all logs as one big string with line-breaks
    let raw = rmesg::logs_raw(opts.backend, opts.clear).unwrap();
    print!("{}", raw)

    // Read logs as a Vec of Entry'ies (`Vec<Entry>`)
    // and can be processed entry-by-entry
    let entries = rmesg::log_entries(opts.backend, opts.clear).unwrap();
    for entry in entries {
        println!("{}", entry)
    }

无限迭代

使用特性sync（即同步），提供一个Result<Entry, RMesgError>的Iterator。

    use rmesg;

    let entries = rmesg::logs_iter(opts.backend, opts.clear, opts.raw)?;
    for maybe_entry in entries {
        let entry = maybe_entry?;
        println!("{}", entry);
    }

使用特性async（即异步），提供一个Result<Entry, RMesgError>的Stream。

    use rmesg;

    // given that it's a stream over Result's, use the conveniences provided to us
    use futures_util::stream::TryStreamExt;

    let mut entries = rmesg::logs_stream(opts.backend, opts.clear, opts.raw).await?;

    while let Some(entry) = entries.try_next().await? {
        println!("{}", entry);
    }