Crate sysinfo

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sysinfo

sysinfo is a crate used to get a system’s information.

Supported OSes

It currently supports the following OSes (alphabetically sorted):

  • Android
  • FreeBSD
  • iOS
  • Linux
  • macOS
  • Raspberry Pi
  • Windows

You can still use sysinfo on non-supported OSes, it’ll simply do nothing and always return empty values. You can check in your program directly if an OS is supported by checking the SystemExt::IS_SUPPORTED constant.

The minimum-supported version of rustc is 1.59.

Usage

⚠️ Before any attempt to read the different structs’ information, you need to update them to get up-to-date information because for most of them, it works on diff between the current value and the old one.

Which is why, it’s much better to keep the same instance of System around instead of recreating it multiple times.

You have an example into the examples folder. You can run it with cargo run --example simple.

Otherwise, here is a little code sample:

use sysinfo::{NetworkExt, NetworksExt, ProcessExt, System, SystemExt};

// Please note that we use "new_all" to ensure that all list of
// components, network interfaces, disks and users are already
// filled!
let mut sys = System::new_all();

// First we update all information of our `System` struct.
sys.refresh_all();

// We display all disks' information:
println!("=> disks:");
for disk in sys.disks() {
    println!("{:?}", disk);
}

// Network interfaces name, data received and data transmitted:
println!("=> networks:");
for (interface_name, data) in sys.networks() {
    println!("{}: {}/{} B", interface_name, data.received(), data.transmitted());
}

// Components temperature:
println!("=> components:");
for component in sys.components() {
    println!("{:?}", component);
}

println!("=> system:");
// RAM and swap information:
println!("total memory: {} bytes", sys.total_memory());
println!("used memory : {} bytes", sys.used_memory());
println!("total swap  : {} bytes", sys.total_swap());
println!("used swap   : {} bytes", sys.used_swap());

// Display system information:
println!("System name:             {:?}", sys.name());
println!("System kernel version:   {:?}", sys.kernel_version());
println!("System OS version:       {:?}", sys.os_version());
println!("System host name:        {:?}", sys.host_name());

// Number of CPUs:
println!("NB CPUs: {}", sys.cpus().len());

// Display processes ID, name na disk usage:
for (pid, process) in sys.processes() {
    println!("[{}] {} {:?}", pid, process.name(), process.disk_usage());
}

Please remember that to have some up-to-date information, you need to call the equivalent refresh method. For example, for the CPU usage:

use sysinfo::{CpuExt, System, SystemExt};

let mut sys = System::new();

loop {
    sys.refresh_cpu(); // Refreshing CPU information.
    for cpu in sys.cpus() {
        print!("{}% ", cpu.cpu_usage());
    }
    // Sleeping for 500 ms to let time for the system to run for long
    // enough to have useful information.
    std::thread::sleep(std::time::Duration::from_millis(500));
}

By default, sysinfo uses multiple threads. However, this can increase the memory usage on some platforms (macOS for example). The behavior can be disabled by setting default-features = false in Cargo.toml (which disables the multithread cargo feature).

Good practice / Performance tips

Most of the time, you don’t want all information provided by sysinfo but just a subset of it. In this case, it’s recommended to use refresh_specifics(...) methods with only what you need to have much better performance.

Another issues frequently encountered: unless you know what you’re doing, it’s almost all the time better to instantiate the System struct once and use this one instance through your program. The reason is because a lot of information needs a previous measure to be computed (the CPU usage for example). Another example why it’s much better: in case you want to list all running processes, sysinfo needs to allocate all memory for the Process struct list, which takes quite some time on the first run.

If your program needs to use a lot of file descriptors, you’d better use:

sysinfo::set_open_files_limit(0);

as sysinfo keeps a number of file descriptors open to have better performance on some targets when refreshing processes.

Running on Raspberry Pi

It’ll be difficult to build on Raspberry Pi. A good way-around is to cross-build, then send the executable to your Raspberry Pi.

First install the arm toolchain, for example on Ubuntu:

> sudo apt-get install gcc-multilib-arm-linux-gnueabihf

Then configure cargo to use the corresponding toolchain:

cat << EOF > ~/.cargo/config
[target.armv7-unknown-linux-gnueabihf]
linker = "arm-linux-gnueabihf-gcc"
EOF

Finally, cross compile:

rustup target add armv7-unknown-linux-gnueabihf
cargo build --target=armv7-unknown-linux-gnueabihf

Linux on Docker & Windows Subsystem for Linux (WSL)

Virtual Linux systems, such as those run through Docker and Windows Subsystem for Linux (WSL), do not receive host hardware information via /sys/class/hwmon or /sys/class/thermal. As such, querying for components may return no results (or unexpected results) when using this library on virtual systems.

Use in binaries running inside the macOS or iOS Sandbox/stores

Apple has restrictions as to which APIs can be linked into binaries that are distributed through the app store. By default, sysinfo is not compatible with these restrictions. You can use the apple-app-store feature flag to disable the Apple prohibited features. This also enables the apple-sandbox feature. In the case of applications using the sandbox outside of the app store, the apple-sandbox feature can be used alone to avoid causing policy violations at runtime.

How it works

I wrote a blog post you can find here which explains how sysinfo extracts information on the different systems.

C interface

It’s possible to use this crate directly from C. Take a look at the Makefile and at the examples/simple.c file.

To build the C example, just run:

> make
> ./simple
# If needed:
> LD_LIBRARY_PATH=target/release/ ./simple

Benchmarks

You can run the benchmarks locally with rust nightly by doing:

> cargo bench

Donations

If you appreciate my work and want to support me, you can do it with github sponsors or with patreon.

Structs

  • Component
    Struct containing a component information (temperature and name for the moment).
  • Cpu
    Struct containing information of a CPU.
  • CpuRefreshKind
    Used to determine what you want to refresh specifically on the Cpu type.
  • Disk
    Struct containing a disk information.
  • DiskUsage
    Type containing read and written bytes.
  • Gid
    A group id wrapping a platform specific type.
  • LoadAvg
    A struct representing system load average value.
  • MacAddr
    MAC address for network interface.
  • NetworkData
    Contains network interface information.
  • Networks
    Networks interfaces.
  • NetworksIter
    Iterator over network interfaces.
  • Pid
    Process ID.
  • Process
    Struct containing information of a process.
  • ProcessRefreshKind
    Used to determine what you want to refresh specifically on the Process type.
  • RefreshKind
    Used to determine what you want to refresh specifically on the System type.
  • System
    Structs containing system’s information.
  • Uid
    A user id wrapping a platform specific type.
  • User
    Type containing user information.

Enums

  • DiskType
    Enum containing the different supported disks types.
  • ProcessStatus
    Enum describing the different status of a process.
  • Signal
    An enum representing signals on UNIX-like systems.

Traits

Functions

  • get_current_pid
    Returns the pid for the current process.
  • set_open_files_limit
    This function is only used on Linux targets, on the other platforms it does nothing and returns false.