[PATCH perl-rs v2 13/40] pve-rs: resource-scheduling: use generic usage implementation

[Daniel Kral <d.kral@proxmox.com>]

The proxmox_resource_scheduling crate provides a generic usage
implementation, which is backwards compatible with the pve_static
bindings. This reduces the static resource scheduling bindings to a
slightly thinner wrapper.

This also exposes the new `add_resource(...)` binding, which allows
callers to add services with additional state other than the usage
stats. It is exposed as `add_service(...)` to be consistent with the
naming of the rest of the existing methods.

Where it is sensible for the bindings, the documentation is extended
with a link to the documentation of the underlying methods.

Signed-off-by: Daniel Kral <d.kral@proxmox.com>
---
changes v1 -> v2:
- add patch message for context
- change from only creating the
  proxmox_resource_scheduling::scheduler::ClusterUsage (now,
  proxmox_resource_scheduling::scheduler::Scheduler), to using the new
  but backwards-compatible `Usage` implementation instead
- this essentially also squashes the 'store services stats independently
  of node' patch in here as this is also tracked by the generic `Usage`
  impl
- add `usage` and `resource` crate for shared code

 .../src/bindings/resource_scheduling/mod.rs   |   3 +
 .../resource_scheduling/pve_static.rs         | 152 ++++++------------
 .../bindings/resource_scheduling/resource.rs  |  44 +++++
 .../src/bindings/resource_scheduling/usage.rs |  33 ++++
 4 files changed, 132 insertions(+), 100 deletions(-)
 create mode 100644 pve-rs/src/bindings/resource_scheduling/resource.rs
 create mode 100644 pve-rs/src/bindings/resource_scheduling/usage.rs

diff --git a/pve-rs/src/bindings/resource_scheduling/mod.rs b/pve-rs/src/bindings/resource_scheduling/mod.rs
index af1fb6b..9ce631c 100644
--- a/pve-rs/src/bindings/resource_scheduling/mod.rs
+++ b/pve-rs/src/bindings/resource_scheduling/mod.rs
@@ -1,4 +1,7 @@
 //! Resource scheduling related bindings.
 
+mod resource;
+mod usage;
+
 mod pve_static;
 pub use pve_static::pve_rs_resource_scheduling_static;
diff --git a/pve-rs/src/bindings/resource_scheduling/pve_static.rs b/pve-rs/src/bindings/resource_scheduling/pve_static.rs
index a83a9ab..3d9f142 100644
--- a/pve-rs/src/bindings/resource_scheduling/pve_static.rs
+++ b/pve-rs/src/bindings/resource_scheduling/pve_static.rs
@@ -6,40 +6,34 @@ pub mod pve_rs_resource_scheduling_static {
     //!
     //! See [`proxmox_resource_scheduling`].
 
-    use std::collections::{HashMap, HashSet};
     use std::sync::Mutex;
 
-    use anyhow::{Error, bail};
+    use anyhow::Error;
 
     use perlmod::Value;
-    use proxmox_resource_scheduling::pve_static::{StaticNodeUsage, StaticServiceUsage};
+    use proxmox_resource_scheduling::node::NodeStats;
+    use proxmox_resource_scheduling::pve_static::StaticServiceUsage;
+    use proxmox_resource_scheduling::usage::Usage;
+
+    use crate::bindings::resource_scheduling::{
+        resource::PveResource, usage::StartedResourceAggregator,
+    };
 
     perlmod::declare_magic!(Box<Scheduler> : &Scheduler as "PVE::RS::ResourceScheduling::Static");
 
-    struct StaticNodeInfo {
-        name: String,
-        maxcpu: usize,
-        maxmem: usize,
-        services: HashMap<String, StaticServiceUsage>,
-    }
-
-    struct Usage {
-        nodes: HashMap<String, StaticNodeInfo>,
-        service_nodes: HashMap<String, HashSet<String>>,
-    }
-
-    /// A scheduler instance contains the resource usage by node.
+    /// A scheduler instance contains the cluster usage.
     pub struct Scheduler {
         inner: Mutex<Usage>,
     }
 
+    type StaticResource = PveResource<StaticServiceUsage>;
+
     /// Class method: Create a new [`Scheduler`] instance.
+    ///
+    /// See [`proxmox_resource_scheduling::usage::Usage::new`].
     #[export(raw_return)]
     pub fn new(#[raw] class: Value) -> Result<Value, Error> {
-        let inner = Usage {
-            nodes: HashMap::new(),
-            service_nodes: HashMap::new(),
-        };
+        let inner = Usage::new();
 
         Ok(perlmod::instantiate_magic!(
             &class, MAGIC => Box::new(Scheduler { inner: Mutex::new(inner) })
@@ -48,7 +42,7 @@ pub mod pve_rs_resource_scheduling_static {
 
     /// Method: Add a node with its basic CPU and memory info.
     ///
-    /// This inserts a [`StaticNodeInfo`] entry for the node into the scheduler instance.
+    /// See [`proxmox_resource_scheduling::usage::Usage::add_node`].
     #[export]
     pub fn add_node(
         #[try_from_ref] this: &Scheduler,
@@ -58,33 +52,24 @@ pub mod pve_rs_resource_scheduling_static {
     ) -> Result<(), Error> {
         let mut usage = this.inner.lock().unwrap();
 
-        if usage.nodes.contains_key(&nodename) {
-            bail!("node {} already added", nodename);
-        }
-
-        let node = StaticNodeInfo {
-            name: nodename.clone(),
+        let stats = NodeStats {
+            cpu: 0.0,
             maxcpu,
+            mem: 0,
             maxmem,
-            services: HashMap::new(),
         };
 
-        usage.nodes.insert(nodename, node);
-        Ok(())
+        usage.add_node(nodename, stats)
     }
 
     /// Method: Remove a node from the scheduler.
+    ///
+    /// See [`proxmox_resource_scheduling::usage::Usage::remove_node`].
     #[export]
     pub fn remove_node(#[try_from_ref] this: &Scheduler, nodename: &str) {
         let mut usage = this.inner.lock().unwrap();
 
-        if let Some(node) = usage.nodes.remove(nodename) {
-            for (sid, _) in node.services.iter() {
-                if let Some(service_nodes) = usage.service_nodes.get_mut(sid) {
-                    service_nodes.remove(nodename);
-                }
-            }
-        }
+        usage.remove_node(nodename);
     }
 
     /// Method: Get a list of all the nodes in the scheduler.
@@ -93,8 +78,7 @@ pub mod pve_rs_resource_scheduling_static {
         let usage = this.inner.lock().unwrap();
 
         usage
-            .nodes
-            .keys()
+            .nodenames_iter()
             .map(|nodename| nodename.to_string())
             .collect()
     }
@@ -104,10 +88,26 @@ pub mod pve_rs_resource_scheduling_static {
     pub fn contains_node(#[try_from_ref] this: &Scheduler, nodename: &str) -> bool {
         let usage = this.inner.lock().unwrap();
 
-        usage.nodes.contains_key(nodename)
+        usage.contains_node(nodename)
+    }
+
+    /// Method: Add `service` with identifier `sid` to the scheduler.
+    ///
+    /// See [`proxmox_resource_scheduling::usage::Usage::add_resource`].
+    #[export]
+    pub fn add_service(
+        #[try_from_ref] this: &Scheduler,
+        sid: String,
+        service: StaticResource,
+    ) -> Result<(), Error> {
+        let mut usage = this.inner.lock().unwrap();
+
+        usage.add_resource(sid, service.try_into()?)
     }
 
     /// Method: Add service `sid` and its `service_usage` to the node.
+    ///
+    /// See [`proxmox_resource_scheduling::usage::Usage::add_resource_usage_to_node`].
     #[export]
     pub fn add_service_usage_to_node(
         #[try_from_ref] this: &Scheduler,
@@ -117,81 +117,33 @@ pub mod pve_rs_resource_scheduling_static {
     ) -> Result<(), Error> {
         let mut usage = this.inner.lock().unwrap();
 
-        match usage.nodes.get_mut(nodename) {
-            Some(node) => {
-                if node.services.contains_key(sid) {
-                    bail!("service '{}' already added to node '{}'", sid, nodename);
-                }
-
-                node.services.insert(sid.to_string(), service_usage);
-            }
-            None => bail!("node '{}' not present in usage hashmap", nodename),
-        }
-
-        if let Some(service_nodes) = usage.service_nodes.get_mut(sid) {
-            if service_nodes.contains(nodename) {
-                bail!("node '{}' already added to service '{}'", nodename, sid);
-            }
-
-            service_nodes.insert(nodename.to_string());
-        } else {
-            let mut service_nodes = HashSet::new();
-            service_nodes.insert(nodename.to_string());
-            usage.service_nodes.insert(sid.to_string(), service_nodes);
-        }
-
-        Ok(())
+        // TODO Only for backwards compatibility, can be removed with a proper version bump
+        #[allow(deprecated)]
+        usage.add_resource_usage_to_node(nodename, sid, service_usage.into())
     }
 
     /// Method: Remove service `sid` and its usage from all assigned nodes.
+    ///
+    /// See [`proxmox_resource_scheduling::usage::Usage::remove_resource`].
     #[export]
     fn remove_service_usage(#[try_from_ref] this: &Scheduler, sid: &str) {
         let mut usage = this.inner.lock().unwrap();
 
-        if let Some(nodes) = usage.service_nodes.remove(sid) {
-            for nodename in &nodes {
-                if let Some(node) = usage.nodes.get_mut(nodename) {
-                    node.services.remove(sid);
-                }
-            }
-        }
+        usage.remove_resource(sid);
     }
 
-    /// Scores all previously added nodes for starting a `service` on.
+    /// Method: Scores nodes to start a service with the usage statistics `service_stats` on.
     ///
-    /// Scoring is done according to the static memory and CPU usages of the nodes as if the
-    /// service would already be running on each.
-    ///
-    /// Returns a vector of (nodename, score) pairs. Scores are between 0.0 and 1.0 and a higher
-    /// score is better.
-    ///
-    /// See [`proxmox_resource_scheduling::pve_static::score_nodes_to_start_service`].
+    /// See [`proxmox_resource_scheduling::scheduler::Scheduler::score_nodes_to_start_resource`].
     #[export]
     pub fn score_nodes_to_start_service(
         #[try_from_ref] this: &Scheduler,
-        service: StaticServiceUsage,
+        service_stats: StaticServiceUsage,
     ) -> Result<Vec<(String, f64)>, Error> {
         let usage = this.inner.lock().unwrap();
-        let nodes = usage
-            .nodes
-            .values()
-            .map(|node| {
-                let mut node_usage = StaticNodeUsage {
-                    name: node.name.to_string(),
-                    cpu: 0.0,
-                    maxcpu: node.maxcpu,
-                    mem: 0,
-                    maxmem: node.maxmem,
-                };
 
-                for service in node.services.values() {
-                    node_usage.add_service_usage(service);
-                }
-
-                node_usage
-            })
-            .collect::<Vec<StaticNodeUsage>>();
-
-        proxmox_resource_scheduling::pve_static::score_nodes_to_start_service(&nodes, &service)
+        usage
+            .to_scheduler::<StartedResourceAggregator>()
+            .score_nodes_to_start_resource(service_stats)
     }
 }
diff --git a/pve-rs/src/bindings/resource_scheduling/resource.rs b/pve-rs/src/bindings/resource_scheduling/resource.rs
new file mode 100644
index 0000000..91d56b9
--- /dev/null
+++ b/pve-rs/src/bindings/resource_scheduling/resource.rs
@@ -0,0 +1,44 @@
+use anyhow::{Error, bail};
+use proxmox_resource_scheduling::resource::{
+    Resource, ResourcePlacement, ResourceState, ResourceStats,
+};
+
+use serde::{Deserialize, Serialize};
+
+/// A PVE resource.
+#[derive(Serialize, Deserialize)]
+pub struct PveResource<T: Into<ResourceStats>> {
+    /// The resource's usage statistics.
+    stats: T,
+    /// Whether the resource is running.
+    running: bool,
+    /// The resource's current node.
+    current_node: Option<String>,
+    /// The resource's optional migration target node.
+    target_node: Option<String>,
+}
+
+impl<T: Into<ResourceStats>> TryFrom<PveResource<T>> for Resource {
+    type Error = Error;
+
+    fn try_from(resource: PveResource<T>) -> Result<Self, Error> {
+        let state = if resource.running {
+            ResourceState::Started
+        } else {
+            ResourceState::Starting
+        };
+
+        let placement = match (resource.current_node, resource.target_node) {
+            (Some(current_node), Some(target_node)) => ResourcePlacement::Moving {
+                current_node,
+                target_node,
+            },
+            (Some(current_node), None) | (None, Some(current_node)) => {
+                ResourcePlacement::Stationary { current_node }
+            }
+            _ => bail!("neither current_node nor target_node are set"),
+        };
+
+        Ok(Resource::new(resource.stats.into(), state, placement))
+    }
+}
diff --git a/pve-rs/src/bindings/resource_scheduling/usage.rs b/pve-rs/src/bindings/resource_scheduling/usage.rs
new file mode 100644
index 0000000..fc8b872
--- /dev/null
+++ b/pve-rs/src/bindings/resource_scheduling/usage.rs
@@ -0,0 +1,33 @@
+use proxmox_resource_scheduling::{
+    scheduler::NodeUsage,
+    usage::{Usage, UsageAggregator},
+};
+
+/// An aggregator, which adds any resource as a started resource.
+///
+/// This aggregator is useful if the node base stats do not have any current usage.
+pub(crate) struct StartedResourceAggregator;
+
+impl UsageAggregator for StartedResourceAggregator {
+    fn aggregate(usage: &Usage) -> Vec<NodeUsage> {
+        usage
+            .nodes_iter()
+            .map(|(nodename, node)| {
+                let stats = node.resources_iter().fold(node.stats(), |node_stats, sid| {
+                    let mut node_stats = node_stats;
+
+                    if let Some(resource) = usage.get_resource(sid) {
+                        node_stats.add_started_resource(&resource.stats());
+                    }
+
+                    node_stats
+                });
+
+                NodeUsage {
+                    name: nodename.to_string(),
+                    stats,
+                }
+            })
+            .collect()
+    }
+}
-- 
2.47.3