api2: add very basic 'status/usage' endpoint for nodes

For returning the nodes basic "usage status", for now one gets memory
and CPU utilization.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

src/api2/node.rs

@@ -8,12 +8,14 @@ mod dns;
 mod syslog;
 mod journal;
 mod services;
+mod status;
 
 pub const SUBDIRS: SubdirMap = &[
     ("dns", &dns::ROUTER),
     ("journal", &journal::ROUTER),
     ("network", &network::ROUTER),
     ("services", &services::ROUTER),
+    ("status", &status::ROUTER),
     ("syslog", &syslog::ROUTER),
     ("tasks", &tasks::ROUTER),
     ("time", &time::ROUTER),

src/api2/node/status.rs

@@ -0,0 +1,77 @@
+use failure::*;
+use serde_json::{json, Value};
+
+use proxmox::sys::linux::procfs;
+
+use proxmox::api::{api, ApiMethod, Router, RpcEnvironment, SubdirMap};
+use proxmox::api::list_subdirs_api_method;
+
+use crate::api2::types::*;
+
+#[api(
+    input: {
+        properties: {
+            node: {
+                schema: NODE_SCHEMA,
+            },
+        },
+    },
+    returns: {
+        type: Object,
+        description: "Returns node memory, CPU and (root) disk usage",
+        properties: {
+            memory: {
+                type: Object,
+                description: "node memory usage counters",
+                properties: {
+                    total: {
+                        description: "total memory",
+                        type: Integer,
+                    },
+                    used: {
+                        description: "total memory",
+                        type: Integer,
+                    },
+                    free: {
+                        description: "free memory",
+                        type: Integer,
+                    },
+                },
+            },
+            cpu: {
+                type: Number,
+                description: "Total CPU usage since last query.",
+                optional: true,
+            },
+        }
+   }
+)]
+/// Read node memory, CPU and (root) disk usage
+fn get_usage(
+    _param: Value,
+    _info: &ApiMethod,
+    _rpcenv: &mut dyn RpcEnvironment,
+) -> Result<Value, Error> {
+
+    let meminfo: procfs::ProcFsMemInfo = procfs::read_meminfo()?;
+    let kstat: procfs::ProcFsStat = procfs::read_proc_stat()?;
+
+    Ok(json!({
+        "memory": {
+            "total": meminfo.memtotal,
+            "used": meminfo.memused,
+            "free": meminfo.memfree,
+        },
+        "cpu": kstat.cpu,
+    }))
+}
+
+pub const USAGE_ROUTER: Router = Router::new()
+    .get(&API_METHOD_GET_USAGE);
+
+pub const SUBDIRS: SubdirMap = &[
+    ("usage", &USAGE_ROUTER),
+];
+pub const ROUTER: Router = Router::new()
+    .get(&list_subdirs_api_method!(SUBDIRS))
+    .subdirs(SUBDIRS);