libvirt.rs

use virt::connect::Connect;

use std::time::Duration;

use crossbeam_channel::Sender;
use serde_derive::Deserialize;

use crate::blocks::{Block, ConfigBlock, Update};
use crate::config::SharedConfig;
use crate::de::deserialize_duration;
use crate::errors::*;
use crate::formatting::value::Value;
use crate::formatting::FormatTemplate;
use crate::scheduler::Task;
use crate::widgets::text::TextWidget;
use crate::widgets::I3BarWidget;
use crate::widgets::State;

pub struct Libvirt {
    id: usize,
    text: TextWidget,
    format: FormatTemplate,
    update_interval: Duration,
    qemu_conn: Connect,
}

impl Libvirt {
    fn check_and_reconnect(&self) -> Result<Self> {
        match self
            .qemu_conn
            .is_alive()
            .block_error("virt", "error when getting connection status to libvirt")
        {
            Ok(true) => {}
            Ok(false) => {
                new = self.clone();
                new.qemu_conn = Connect::open_read_only(
                    &self
                        .qemu_conn
                        .get_uri()
                        .block_error("virt", "error in retrieving URI information from libvirt")
                        .unwrap(), /* Only happens if memory corruption; then we should panic anyway */
                )
                .block_error("virt", "error in reconnecting to libvirt socket")?;
                return Ok(new);
            }
            Err(e) => {
                return Err(e);
            }
        };
    }
}

#[derive(Deserialize, Debug, Clone)]
#[serde(deny_unknown_fields, default)]
pub struct LibvirtConfig {
    /// Update interval in seconds
    #[serde(deserialize_with = "deserialize_duration")]
    pub interval: Duration,

    /// Format override
    pub format: FormatTemplate,

    /// URL to QEMU
    pub qemu_url: String,
}

impl Default for LibvirtConfig {
    fn default() -> Self {
        Self {
            interval: Duration::from_secs(5),
            format: FormatTemplate::default(),
            qemu_url: "qemu:///system".to_string(),
        }
    }
}

impl ConfigBlock for Libvirt {
    type Config = LibvirtConfig;

    fn new(
        id: usize,
        block_config: Self::Config,
        shared_config: SharedConfig,
        _: Sender<Task>,
    ) -> Result<Self> {
        let text = TextWidget::new(id, 0, shared_config)
            .with_text("vms")
            .with_icon("virtual-machine")?;

        let qemu_conn = Connect::open_read_only(&block_config.qemu_url)
            .block_error("virt", "error when connecting to libvirt")?;

        Ok(Libvirt {
            id,
            text,
            format: block_config.format.with_default("{running}")?,
            update_interval: block_config.interval,
            qemu_conn,
        })
    }
}

impl Block for Libvirt {
    fn update(&mut self) -> Result<Option<Update>> {
        // Check if the connection is still active and re-instatiate it if it's not
        self.check_and_reconnect()?;

        let paused: i64 = match self
            .qemu_conn
            .list_all_domains(1 << 5)
            .block_error("virt", "unable to get paused domains")
        {
            Ok(d) => d.len() as i64,
            Err(e) => {
                self.text.set_state(State::Critical);
                return Err(e);
            }
        };

        self.check_and_reconnect()?;

        let stopped: i64 = match self
            .qemu_conn
            .num_of_defined_domains()
            .block_error("virt", "unable to get stopped domains")
        {
            Ok(d) => d as i64,
            Err(e) => {
                self.text.set_state(State::Critical);
                return Err(e);
            }
        };

        self.check_and_reconnect()?;

        let running = match self
            .qemu_conn
            .list_all_domains(1 << 4)
            .block_error("virt", "unable to get running domains")
        {
            Ok(d) => d.len() as i64,
            Err(e) => {
                self.text.set_state(State::Critical);
                return Err(e);
            }
        };

        let total = running + stopped + paused;

        self.check_and_reconnect()?;

        let mut num_images: i64 = 0;
        match self
            .qemu_conn
            .list_all_storage_pools(1 << 1)
            .block_error("virt", "could not get list of storage pools from libvirt")
        {
            Ok(pools) => {
                for pool in pools {
                    num_images += match pool
                        .num_of_volumes()
                        .block_error("virt", "could not count volumes in storage pool")
                    {
                        Ok(n) => n as i64,
                        Err(e) => {
                            self.text.set_state(State::Critical);
                            return Err(e);
                        }
                    }
                }
            }
            Err(e) => {
                self.text.set_state(State::Critical);
                return Err(e);
            }
        };

        let values = map!(
            "total" =>   Value::from_integer(total),
            "running" => Value::from_integer(running),
            "paused" =>  Value::from_integer(paused),
            "stopped" => Value::from_integer(stopped),
            "images" =>  Value::from_integer(num_images),
        );

        self.text.set_texts(self.format.render(&values)?);
        self.text.set_state(State::Idle);

        Ok(Some(self.update_interval.into()))
    }

    fn view(&self) -> Vec<&dyn I3BarWidget> {
        vec![&self.text]
    }

    fn id(&self) -> usize {
        self.id
    }
}