Implement events command for cgroup v1 stats

src/cgroups/v1/blkio.rs

@@ -138,11 +138,13 @@ impl Blkio {
     }
 
     fn get_throttling_policy_stats(cgroup_path: &Path) -> Result<BlkioStats> {
-        let mut stats = BlkioStats::default();
-
-        stats.service_bytes =
-            Self::parse_blkio_file(&cgroup_path.join(BLKIO_THROTTLE_IO_SERVICE_BYTES))?;
-        stats.serviced = Self::parse_blkio_file(&cgroup_path.join(BLKIO_THROTTLE_IO_SERVICED))?;
+        let stats = BlkioStats {
+            service_bytes: Self::parse_blkio_file(
+                &cgroup_path.join(BLKIO_THROTTLE_IO_SERVICE_BYTES),
+            )?,
+            serviced: Self::parse_blkio_file(&cgroup_path.join(BLKIO_THROTTLE_IO_SERVICED))?,
+            ..Default::default()
+        };
 
         Ok(stats)
     }

src/cgroups/v1/memory.rs

@@ -166,10 +166,7 @@ impl Memory {
     fn hierarchy_enabled(cgroup_path: &Path) -> Result<bool> {
         let hierarchy_path = cgroup_path.join(MEMORY_USE_HIERARCHY);
         let hierarchy = common::read_cgroup_file(hierarchy_path)?;
-        let enabled = match hierarchy.trim() {
-            "1" => true,
-            _ => false,
-        };
+        let enabled = matches!(hierarchy.trim(), "1");
 
         Ok(enabled)
     }

src/cgroups/v2/manager.rs

@@ -157,6 +157,6 @@ impl CgroupManager for Manager {
     }
 
     fn stats(&self) -> Result<Stats> {
-        todo!();
+        Ok(Stats::default())
     }
 }

src/cgroups/v2/systemd_manager.rs

@@ -257,7 +257,7 @@ impl CgroupManager for SystemDCGroupManager {
     }
 
     fn stats(&self) -> Result<Stats> {
-        todo!();
+        Ok(Stats::default())
     }
 }
 

src/commands/events.rs

@@ -0,0 +1,57 @@
+use crate::{cgroups::common, utils};
+use clap::Clap;
+use std::{path::PathBuf, thread, time::Duration};
+
+use anyhow::{bail, Context, Result};
+
+use crate::container::{Container, ContainerStatus};
+
+#[derive(Clap, Debug)]
+pub struct Events {
+    /// Sets the stats collection interval in seconds (default: 5s)
+    #[clap(long, default_value = "5")]
+    pub interval: u32,
+    /// Display the container stats only once
+    #[clap(long)]
+    pub stats: bool,
+    /// Name of the container instance
+    pub container_id: String,
+}
+
+impl Events {
+    pub fn exec(&self, root_path: PathBuf) -> Result<()> {
+        let container_dir = root_path.join(&self.container_id);
+        if !container_dir.exists() {
+            log::debug!("{:?}", container_dir);
+            bail!("{} doesn't exist.", self.container_id)
+        }
+
+        let container = Container::load(container_dir)?.refresh_status()?;
+        if !container.state.status.eq(&ContainerStatus::Running) {
+            bail!("{} is not in running state", self.container_id);
+        }
+
+        let cgroups_path = utils::get_cgroup_path(
+            &container
+                .spec()?
+                .linux
+                .context("no linux in spec")?
+                .cgroups_path,
+            &self.container_id,
+        );
+        let use_systemd = container
+            .systemd()
+            .context("Could not determine cgroup manager")?;
+
+        let cgroup_manager = common::create_cgroup_manager(cgroups_path, use_systemd)?;
+        match self.stats {
+            true => println!("{:#?}", cgroup_manager.stats()),
+            false => loop {
+                println!("{:#?}", cgroup_manager.stats());
+                thread::sleep(Duration::from_secs(self.interval as u64));
+            },
+        }
+
+        Ok(())
+    }
+}

src/commands/mod.rs

@@ -1,5 +1,6 @@
 pub mod create;
 pub mod delete;
+pub mod events;
 pub mod exec;
 pub mod info;
 pub mod kill;

src/main.rs

@@ -10,6 +10,7 @@ use clap::Clap;
 
 use youki::commands::create;
 use youki::commands::delete;
+use youki::commands::events;
 use youki::commands::exec;
 use youki::commands::info;
 use youki::commands::kill;
@@ -71,6 +72,8 @@ enum SubCommand {
     Pause(pause::Pause),
     #[clap(version = "0.0.1", author = "utam0k <k0ma@utam0k.jp>")]
     Resume(resume::Resume),
+    #[clap(version = "0.0.1", author = "utam0k <k0ma@utam0k.jp>")]
+    Events(events::Events),
 }
 
 /// This is the entry point in the container runtime. The binary is run by a high-level container runtime,
@@ -104,5 +107,6 @@ fn main() -> Result<()> {
         SubCommand::Spec(spec) => spec.exec(),
         SubCommand::Pause(pause) => pause.exec(root_path, systemd_cgroup),
         SubCommand::Resume(resume) => resume.exec(root_path, systemd_cgroup),
+        SubCommand::Events(events) => events.exec(root_path),
     }
 }