DLPX-80877 add zcache status command (openzfs#488)

cmd/zfs_object_agent/util/src/lib.rs

@@ -27,6 +27,7 @@ pub mod watch_once;
 pub mod write_stdout;
 mod zcache_devices;
 mod zcache_hits;
+mod zcache_status;
 pub mod zettacache_stats;
 
 pub use alloc::with_alloctag;
@@ -60,3 +61,6 @@ pub use write_stdout::flush_stdout;
 pub use zcache_devices::DeviceEntry;
 pub use zcache_devices::DeviceList;
 pub use zcache_hits::ReportHitsResponse;
+pub use zcache_status::DeviceStatus;
+pub use zcache_status::IndexStatus;
+pub use zcache_status::ZcacheStatus;

cmd/zfs_object_agent/util/src/message.rs

@@ -136,6 +136,7 @@ pub const TYPE_REPORT_HITS: &str = "report hits";
 pub const TYPE_LIST_DEVICES: &str = "list devices";
 pub const TYPE_ZCACHE_IOSTAT: &str = "zcache iostat";
 pub const TYPE_ZCACHE_STATS: &str = "zcache stats";
+pub const TYPE_ZCACHE_STATUS: &str = "zcache status";
 pub const TYPE_ADD_DISK: &str = "add disk";
 pub const TYPE_EXPAND_DISK: &str = "expand disk";
 pub const TYPE_SYNC_CHECKPOINT: &str = "sync checkpoint";

cmd/zfs_object_agent/util/src/zcache_status.rs

@@ -0,0 +1,29 @@
+//! This module provides common zcache structures that are collected by
+//! the **zettacache** runtime and consumed by **zcache** subcommands.
+//! These structures on the zettacache side are serialized and then deserialized
+//! by the zettacache subcommands.
+
+use std::path::PathBuf;
+
+use serde::Deserialize;
+use serde::Serialize;
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+pub struct IndexStatus {
+    pub bytes: u64,
+    pub entries: u64,
+    pub pending_changes: u64,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct DeviceStatus {
+    pub path: PathBuf,
+    pub canonical_path: PathBuf,
+    pub size: u64,
+}
+
+#[derive(Debug, Default, Serialize, Deserialize)]
+pub struct ZcacheStatus {
+    pub index: IndexStatus,
+    pub devices: Vec<DeviceStatus>,
+}

cmd/zfs_object_agent/zcache/src/iostat.rs

@@ -248,9 +248,9 @@ impl IoStatDisplay {
         for disk_stat in stat_delta.disk_stats.iter() {
             if self.show_time {
                 if self.interval_is_subsecond {
-                    writeln_stdout!("{}", Local::now().format("%Y-%m-%d %H:%M:%S%.3f UTC"));
+                    writeln_stdout!("{}", Local::now().format("%Y-%m-%d %H:%M:%S%.3f %z"));
                 } else {
-                    writeln_stdout!("{}", Local::now().format("%Y-%m-%d %H:%M:%S UTC"));
+                    writeln_stdout!("{}", Local::now().format("%Y-%m-%d %H:%M:%S %z"));
                 }
             }
             writeln_stdout!();

cmd/zfs_object_agent/zcache/src/main.rs

@@ -13,6 +13,7 @@ mod labelclear;
 mod list;
 mod remote_channel;
 mod stats;
+mod status;
 mod subcommand;
 mod sync;
 
@@ -63,6 +64,7 @@ enum Commands {
     Expand(expand::Expand),
     Sync(sync::Sync),
     Labelclear(labelclear::Labelclear),
+    Status(status::Status),
 
     // clear_hit_data is deprecated/hidden
     #[clap(rename_all = "snake_case")]
@@ -81,6 +83,7 @@ impl Commands {
             Commands::Sync(sync) => sync,
             Commands::Labelclear(labelclear) => labelclear,
             Commands::ClearHitData(clear_hit_data) => clear_hit_data,
+            Commands::Status(status) => status,
         }
     }
 }

cmd/zfs_object_agent/zcache/src/status.rs

@@ -0,0 +1,147 @@
+//! `zcache status` subcommand
+
+use std::thread::sleep;
+use std::time::Duration;
+
+use anyhow::Result;
+use async_trait::async_trait;
+use chrono::Local;
+use clap::Parser;
+use util::flush_stdout;
+use util::message::TYPE_ZCACHE_STATUS;
+use util::nice_p2size;
+use util::write_stdout;
+use util::writeln_stdout;
+use util::DeviceStatus;
+use util::ZcacheStatus;
+
+use crate::remote_channel::RemoteChannel;
+use crate::subcommand::ZcacheSubCommand;
+
+#[derive(Parser)]
+#[clap(about = "Display zettacache status.")]
+pub struct Status {
+    /// Display a timestamp
+    #[clap(short = 't', long)]
+    timestamp: bool,
+
+    /// Display real paths for devices resolving all symbolic links.
+    #[clap(short = 'r', long)]
+    real_paths: bool,
+
+    /// Use JSON output format.
+    #[clap(
+        short = 'j',
+        long,
+        conflicts_with = "timestamp",
+        conflicts_with = "real-paths"
+    )]
+    json: bool,
+
+    /// Status is printed every <interval> seconds
+    #[clap()]
+    interval: Option<f64>,
+
+    /// Stop after <count> status reports have been displayed
+    #[clap()]
+    count: Option<u64>,
+}
+
+impl Status {
+    // Maximum width from the set of possible keys ("devices", "index", etc.)
+    const MAXIMUM_KEY_WIDTH: usize = 7;
+
+    /// Derive the device path to display
+    fn derive_path(&self, device_status: &DeviceStatus) -> String {
+        let device_path = if self.real_paths {
+            &device_status.canonical_path
+        } else {
+            &device_status.path
+        };
+        device_path.to_string_lossy().into()
+    }
+
+    fn max_path_length(&self, devices: &[DeviceStatus]) -> usize {
+        devices
+            .iter()
+            .map(|d| self.derive_path(d).len())
+            .max()
+            .unwrap_or_default()
+    }
+
+    fn cli_status(&self, status: &ZcacheStatus) {
+        if self.timestamp {
+            writeln_stdout!("{}", Local::now().to_rfc2822());
+        }
+
+        // Display index status
+        writeln_stdout!(
+            "{:>3$}: current size {} with {} pending changes",
+            "index",
+            nice_p2size(status.index.bytes),
+            status.index.pending_changes,
+            Status::MAXIMUM_KEY_WIDTH
+        );
+
+        // Display devices status
+        let path_width = self.max_path_length(&status.devices);
+        writeln_stdout!("{:>1$}:", "devices", Status::MAXIMUM_KEY_WIDTH);
+        for device_status in status.devices.iter() {
+            // example: "         /dev/nvme6n1p2  56.0GB  <status>"
+            write_stdout!(
+                "{:>3$}{:<4$}  {:>6}",
+                "",
+                self.derive_path(device_status),
+                nice_p2size(device_status.size),
+                Status::MAXIMUM_KEY_WIDTH + 2,
+                path_width,
+            );
+
+            // ToDo: write optional device status column here
+
+            writeln_stdout!();
+        }
+    }
+
+    fn json_status(&self, status: &ZcacheStatus) {
+        writeln_stdout!("{}", serde_json::to_string_pretty(&status).unwrap());
+    }
+
+    async fn display_status(&self) -> Result<()> {
+        let interval = self.interval.map(Duration::from_secs_f64);
+        let mut iteration = 0;
+        let mut remote = RemoteChannel::new(false).await?;
+
+        loop {
+            let response = remote.call(TYPE_ZCACHE_STATUS, None).await?;
+            let status_json = response.lookup_string("status_json")?;
+            let status: ZcacheStatus = serde_json::from_str(status_json.to_str()?)?;
+            if self.json {
+                self.json_status(&status);
+            } else {
+                self.cli_status(&status);
+                flush_stdout()?;
+            }
+
+            let interval: Duration = match interval {
+                None => return Ok(()),
+                Some(interval) => interval,
+            };
+
+            iteration += 1;
+            if let Some(count) = self.count {
+                if iteration >= count {
+                    return Ok(());
+                }
+            }
+            sleep(interval);
+        }
+    }
+}
+
+#[async_trait]
+impl ZcacheSubCommand for Status {
+    async fn invoke(&self) -> Result<()> {
+        self.display_status().await
+    }
+}

cmd/zfs_object_agent/zettacache/src/block_access.rs

@@ -47,6 +47,7 @@ use util::AlignedBytes;
 use util::AlignedVec;
 use util::DeviceEntry;
 use util::DeviceList;
+use util::DeviceStatus;
 use util::From64;
 use uuid::Uuid;
 
@@ -662,7 +663,7 @@ impl BlockAccess {
             })
     }
 
-    // Gather a list of devices for zcache list_devices command.
+    /// Gather a list of devices for `zcache list` command.
     pub fn list_devices(&self) -> DeviceList {
         let devices = self
             .disks
@@ -677,6 +678,20 @@ impl BlockAccess {
         DeviceList { devices }
     }
 
+    /// Gather a list of devices with status for `zcache status` command.
+    pub fn list_device_status(&self) -> Vec<DeviceStatus> {
+        self.disks
+            .read()
+            .unwrap()
+            .iter()
+            .map(|d| DeviceStatus {
+                path: d.path.clone(),
+                canonical_path: d.canonical_path.clone(),
+                size: *d.size.lock().unwrap(),
+            })
+            .collect()
+    }
+
     pub fn disk_size(&self, disk: DiskId) -> u64 {
         *self.disks.read().unwrap()[disk.index()]
             .size

cmd/zfs_object_agent/zettacache/src/zettacache/mod.rs

@@ -13,6 +13,7 @@ use std::mem;
 use std::mem::size_of;
 use std::path::Path;
 use std::path::PathBuf;
+use std::sync::atomic::Ordering::Relaxed;
 use std::sync::Arc;
 use std::time::Duration;
 use std::time::Instant;
@@ -61,8 +62,10 @@ use util::zettacache_stats::IoStatsRef;
 use util::AlignedBytes;
 use util::DeviceList;
 use util::From64;
+use util::IndexStatus;
 use util::LockSet;
 use util::LockedItem;
+use util::ZcacheStatus;
 use uuid::Uuid;
 
 use self::merge::MergeMessage;
@@ -431,6 +434,13 @@ impl ZettaCache {
         }
     }
 
+    pub async fn status(&self) -> ZcacheStatus {
+        match &*self.inner.load() {
+            Some(inner) => inner.status().await,
+            None => Default::default(),
+        }
+    }
+
     pub fn io_stats<'a>(&self) -> IoStatsRef<'a> {
         match &*self.inner.load() {
             Some(inner) => inner.io_stats(),
@@ -1533,6 +1543,20 @@ impl Inner {
         self.block_access.list_devices()
     }
 
+    async fn status(&self) -> ZcacheStatus {
+        let indices = self.indices.read().await;
+        let pending_changes = &self.stats.stats[PendingChanges];
+
+        ZcacheStatus {
+            index: IndexStatus {
+                bytes: indices.old.num_bytes(),
+                entries: indices.old.len(),
+                pending_changes: pending_changes.0.load(Relaxed),
+            },
+            devices: self.block_access.list_device_status(),
+        }
+    }
+
     fn io_stats<'a>(&self) -> IoStatsRef<'a> {
         self.block_access.io_stats(self.cache_runtime_id)
     }

cmd/zfs_object_agent/zettaobject/src/public_connection.rs

@@ -90,6 +90,7 @@ impl PublicConnectionState {
         server.register_handler(TYPE_LIST_DEVICES, Box::new(Self::list_devices));
         server.register_handler(TYPE_ZCACHE_IOSTAT, Box::new(Self::zcache_iostat));
         server.register_handler(TYPE_ZCACHE_STATS, Box::new(Self::zcache_stats));
+        server.register_handler(TYPE_ZCACHE_STATUS, Box::new(Self::zcache_status));
     }
 
     fn get_pools(&mut self, nvl: NvList) -> HandlerReturn {
@@ -242,6 +243,21 @@ impl PublicConnectionState {
             return_ok(response, false)
         }))
     }
+
+    fn zcache_status(&mut self, _: NvList) -> HandlerReturn {
+        let cache = self.cache.clone();
+        debug!("got StatusRequest");
+        Ok(Box::pin(async move {
+            #[derive(Debug, Serialize)]
+            struct StatusResponse {
+                status_json: String,
+            }
+            let response = StatusResponse {
+                status_json: serde_json::to_string(&cache.status().await).unwrap(),
+            };
+            return_ok(response, true)
+        }))
+    }
 }
 
 async fn discover_pools(object_access: Arc<ObjectAccess>, pools: Arc<Mutex<NvList>>) {