Crate tokio_console

Expand description

tokio-console CLI

🎛️ The Tokio console: a debugger for asynchronous Rust programs.

tokio-console is a debugging and profiling tool for asynchronous Rust applications, which collects and displays in-depth diagnostic data on the asynchronous tasks, resources, and operations in an application. The console system consists of two primary components:

📡️ instrumentation, embedded in the application, which collects data from the async runtime and exposes it over the console’s wire format
🛰️ consumers, which connect to the instrumented application, recieve telemetry data, and display it to the user

This crate is the primary consumer of tokio-console telemetry, a command-line application that provides an interactive debugging interface.

Getting Started

To use the console CLI to debug an asynchronous application, the application must first be instrumented to record tokio-console telemetry. The easiest way to do this is using the console-subscriber crate.

Once the application is instrumented, install the console CLI using

cargo install tokio-console

Running tokio-console without any arguments will connect to an application on localhost listening on the default port, port 6669:

tokio-console

If the application is not running locally, or was configured to listen on a different port, the console will also accept a target address as a command-like argument:

tokio-console http://192.168.0.42:9090

A DNS name can also be provided as the target address:

tokio-console http://my.instrumented.application.local:6669

When the console CLI is launched, it displays a list of all asynchronous tasks in the program:

tasks list

Using the ↑ and ↓ arrow keys, an individual task can be highlighted. Pressingenter while a task is highlighted displays details about that task:

task details

Pressing the escape key returns to the task list.

The r key switches from the list of tasks to a list of resources, such as synchronization primitives, I/O resources, et cetera:

resource list

Pressing the t key switches the view back to the task list.

Like the task list view, the resource list view can be navigated using the ↑ and ↓ arrow keys. Pressing enter while a resource is highlighted displays details about that resource:

resource details — oneshot

The resource details view lists the tasks currently waiting on that resource. This may be a single task, as in the tokio::sync::oneshot channel above, or a large number of tasks, such as this tokio::sync::Semaphore:

resource details — semaphore

Like the task details view, pressing the escape key while viewing a resource’s details returns to the resource list.

Command-Line Arguments

Running tokio-console --help displays a list of all available command-line arguments:

$ tokio-console --help

tokio-console 0.1.0

USAGE:
    tokio-console [OPTIONS] [TARGET_ADDR]

ARGS:
    <TARGET_ADDR>
            The address of a console-enabled process to connect to.

            This may be an IP address and port, or a DNS name.

            [default: http://127.0.0.1:6669]

OPTIONS:
        --ascii-only
            Explicitly use only ASCII characters

        --colorterm <truecolor>
            Overrides the value of the `COLORTERM` environment variable.

            If this is set to `24bit` or `truecolor`, 24-bit RGB color support will be enabled.

            [env: COLORTERM=truecolor]
            [possible values: 24bit, truecolor]

    -h, --help
            Print help information

        --lang <LANG>
            Overrides the terminal's default language

            [env: LANG=en_US.UTF-8]
            [default: en_us.UTF-8]

        --log <ENV_FILTER>
            Log level filter for the console's internal diagnostics.

            The console will log to stderr if a log level filter is provided. Since the console
            application runs interactively, stderr should generally be redirected to a file to avoid
            interfering with the console's text output.

            [env: RUST_LOG=]
            [default: off]

        --no-colors
            Disable ANSI colors entirely

        --no-duration-colors
            Disable color-coding for duration units

        --no-terminated-colors
            Disable color-coding for terminated tasks

        --palette <PALETTE>
            Explicitly set which color palette to use

            [possible values: 8, 16, 256, all, off]

        --retain-for <RETAIN_FOR>
            How long to continue displaying completed tasks and dropped resources after they have
            been closed.

            This accepts either a duration, parsed as a combination of time spans (such as `5days
            2min 2s`), or `none` to disable removing completed tasks and dropped resources.

            Each time span is an integer number followed by a suffix. Supported suffixes are:

            * `nsec`, `ns` -- nanoseconds

            * `usec`, `us` -- microseconds

            * `msec`, `ms` -- milliseconds

            * `seconds`, `second`, `sec`, `s`

            * `minutes`, `minute`, `min`, `m`

            * `hours`, `hour`, `hr`, `h`

            * `days`, `day`, `d`

            * `weeks`, `week`, `w`

            * `months`, `month`, `M` -- defined as 30.44 days

            * `years`, `year`, `y` -- defined as 365.25 days

            [default: 6s]

    -V, --version
            Print version information

Getting Help

First, see if the answer to your question can be found in the API documentation. If the answer is not there, there is an active community in the Tokio Discord server. We would be happy to try to answer your question. You can also ask your question on the discussions page.

Crate tokio_console

tokio-console CLI

Overview

Getting Started

Command-Line Arguments

Getting Help

Contributing

Supported Rust Versions

License

Contribution