Add State (#72)

Expose some functions to get the current state for a pool / dataset
or all pools.

These states try to be holistic views of what Pools / Datasets
Properties and VDevs look like at that point in time.

Signed-off-by: Joe Grund <jgrund@whamcloud.io>

Author: jgrund

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "libzfs"
-version = "0.6.8"
+version = "0.6.9"
 authors = ["IML Team <iml@whamcloud.com>"]
 description = "Rust wrapper around libzfs-sys"
 license = "MIT"

libzfs/Cargo.toml

@@ -33,3 +33,6 @@ pub use zpool::Zpool;
 
 pub mod libzfs;
 pub use libzfs::Libzfs;
+
+pub mod state;
+pub use state::*;

libzfs/src/lib.rs

@@ -0,0 +1,125 @@
+// Copyright (c) 2018 DDN. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+//! Get the current state of ZFS on a node
+//!
+//! Uses a `Libzfs` handle to get state at that point.
+//! Collects into a struct that can be serialized using `serde`.
+//!
+
+use std::io;
+
+use libzfs::Libzfs;
+use libzfs_error::Result;
+use vdev::VDev;
+use zfs::Zfs;
+use zpool::Zpool;
+use zprop_list::ZProp;
+
+/// A Pool at a point in time
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Pool {
+    pub name: String,
+    pub guid: String,
+    pub health: String,
+    pub hostname: String,
+    pub hostid: Option<u64>,
+    pub state: String,
+    pub readonly: bool,
+    pub size: String,
+    pub vdev: VDev,
+    pub props: Vec<ZProp>,
+    pub datasets: Vec<Dataset>,
+}
+
+/// A Dataset at a point in time
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Dataset {
+    pub name: String,
+    pub guid: String,
+    pub kind: String,
+    pub props: Vec<ZProp>,
+}
+
+/// Takes a Zfs reference and converts it into a
+/// `Dataset`
+fn convert_to_dataset(x: &Zfs) -> Result<Dataset> {
+    let props = x.props()?;
+
+    let guid = props
+        .iter()
+        .find(|x| x.name == "guid")
+        .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "could not find guid in props"))
+        .map(|x| x.value.clone())?;
+
+    Ok(Dataset {
+        name: x.name().into_string()?,
+        kind: x.zfs_type_name().into_string()?,
+        guid,
+        props,
+    })
+}
+
+/// Takes a Zpool reference and converts it into a
+/// `Pool`
+fn convert_to_js_pool(p: &Zpool) -> Result<Pool> {
+    let xs: Vec<Dataset> = p
+        .datasets()?
+        .iter()
+        .map(convert_to_dataset)
+        .collect::<Result<_>>()?;
+
+    let hostname = p.hostname()?;
+
+    let hostid = p.hostid().ok();
+
+    let health = p.health()?;
+
+    Ok(Pool {
+        name: p.name().into_string()?,
+        health: health.into_string()?,
+        guid: p.guid().to_string(),
+        hostname: hostname.into_string()?,
+        hostid,
+        state: p.state_name().into_string()?,
+        readonly: p.read_only(),
+        size: p.size().to_string(),
+        props: vec![],
+        vdev: p.vdev_tree()?,
+        datasets: xs,
+    })
+}
+
+/// Given a pool name, try to find it and convert it to a `Pool`.
+/// The outer `Option` represents failure to find the pool,
+/// The inner `Result` represents failure during the conversion.
+pub fn get_pool_by_name(pool_name: &str) -> Option<Result<Pool>> {
+    let mut libzfs = Libzfs::new();
+
+    libzfs
+        .pool_by_name(&pool_name)
+        .map(|x| convert_to_js_pool(&x))
+}
+
+/// Given a dataset name, try to find it and convert it to a `Dataset`.
+/// The outer `Option` represents failure to find the dataset,
+/// The inner `Result` represents failure during the conversion.
+pub fn get_dataset_by_name(ds_name: &str) -> Option<Result<Dataset>> {
+    let mut libzfs = Libzfs::new();
+
+    libzfs
+        .dataset_by_name(&ds_name)
+        .map(|x| convert_to_dataset(&x))
+}
+
+/// Return all imported pools on this node.
+/// Returns `Err` if any imported pool fails conversion to `Pool`.
+pub fn get_imported_pools() -> Result<Vec<Pool>> {
+    let mut libzfs = Libzfs::new();
+    libzfs
+        .get_imported_pools()?
+        .iter()
+        .map(convert_to_js_pool)
+        .collect()
+}