guest-agent: Add prometheus metrics API

Author: kvinwang

guest-agent/src/http_routes.rs

@@ -16,7 +16,7 @@ use rocket::{get, response::content::RawHtml, routes, Route, State};
 pub fn external_routes(config: &Config) -> Vec<Route> {
     let mut routes = routes![index];
     if config.public_logs {
-        routes.extend(routes![get_logs]);
+        routes.extend(routes![get_logs, metrics]);
     }
     routes
 }
@@ -69,6 +69,25 @@ async fn index(state: &State<AppState>) -> Result<RawHtml<String>, String> {
     }
 }
 
+// Returns metrics about the guest in prometheus format if public_sysinfo is enabled
+#[get("/metrics")]
+async fn metrics(state: &State<AppState>) -> Result<String, String> {
+    let public_sysinfo = state.config().public_sysinfo;
+    if !public_sysinfo {
+        return Err("Sysinfo API is disabled".to_string());
+    }
+    let context = CallContext::builder().state(&**state).build();
+    let handler = GuestApiHandler::construct(context.clone())
+        .map_err(|e| format!("Failed to construct RPC handler: {}", e))?;
+
+    let system_info = handler.sys_info().await.unwrap_or_default();
+    let model = crate::models::Metrics { system_info };
+    match model.render() {
+        Ok(body) => Ok(body),
+        Err(err) => Err(format!("Failed to render template: {err}")),
+    }
+}
+
 #[get("/logs/<container_name>?<since>&<until>&<follow>&<text>&<timestamps>&<bare>&<tail>&<ansi>")]
 #[allow(clippy::too_many_arguments)]
 fn get_logs(

guest-agent/src/models.rs

@@ -44,3 +44,9 @@ pub struct Dashboard {
     pub public_sysinfo: bool,
     pub public_logs: bool,
 }
+
+#[derive(Template)]
+#[template(path = "metrics.tpl", escape = "none")]
+pub struct Metrics {
+    pub system_info: SystemInfo,
+}

guest-agent/templates/metrics.tpl

@@ -0,0 +1,87 @@
+# HELP system_os_name Operating system name
+# TYPE system_os_name gauge
+system_os_name{os_name="{{system_info.os_name}}"} 1
+
+# HELP system_os_version Operating system version
+# TYPE system_os_version gauge
+system_os_version{os_version="{{system_info.os_version}}"} 1
+
+# HELP system_kernel_version Kernel version
+# TYPE system_kernel_version gauge
+system_kernel_version{kernel_version="{{system_info.kernel_version}}"} 1
+
+# HELP system_cpu_model CPU model information
+# TYPE system_cpu_model gauge
+system_cpu_model{cpu_model="{{system_info.cpu_model}}"} 1
+
+# HELP system_num_cpus Number of logical CPUs
+# TYPE system_num_cpus gauge
+system_num_cpus {{system_info.num_cpus}}
+
+# HELP system_memory_total Total memory in bytes
+# TYPE system_memory_total gauge
+system_memory_total {{system_info.total_memory}}
+
+# HELP system_memory_available Available memory in bytes
+# TYPE system_memory_available gauge
+system_memory_available {{system_info.available_memory}}
+
+# HELP system_memory_used Used memory in bytes
+# TYPE system_memory_used gauge
+system_memory_used {{system_info.used_memory}}
+
+# HELP system_memory_free Free memory in bytes
+# TYPE system_memory_free gauge
+system_memory_free {{system_info.free_memory}}
+
+# HELP system_swap_total Total swap memory in bytes
+# TYPE system_swap_total gauge
+system_swap_total {{system_info.total_swap}}
+
+# HELP system_swap_used Used swap memory in bytes
+# TYPE system_swap_used gauge
+system_swap_used {{system_info.used_swap}}
+
+# HELP system_swap_free Free swap memory in bytes
+# TYPE system_swap_free gauge
+system_swap_free {{system_info.free_swap}}
+
+# HELP system_uptime System uptime in seconds
+# TYPE system_uptime gauge
+system_uptime {{system_info.uptime}}
+
+# HELP system_load_average_1m System load average (1 minute)
+# TYPE system_load_average_1m gauge
+system_load_average_1m {{system_info.loadavg_one}}
+
+# HELP system_load_average_5m System load average (5 minutes)
+# TYPE system_load_average_5m gauge
+system_load_average_5m {{system_info.loadavg_five}}
+
+# HELP system_load_average_15m System load average (15 minutes)
+# TYPE system_load_average_15m gauge
+system_load_average_15m {{system_info.loadavg_fifteen}}
+
+# HELP disk_total_size Disk total size in bytes
+# TYPE disk_total_size gauge
+{% for disk in system_info.disks %}
+disk_total_size{name="{{disk.name}}", mount_point="{{disk.mount_point}}"} {{disk.total_size}}
+{% endfor %}
+
+# HELP disk_free_size Disk free size in bytes
+# TYPE disk_free_size gauge
+{% for disk in system_info.disks %}
+disk_free_size{name="{{disk.name}}", mount_point="{{disk.mount_point}}"} {{disk.free_size}}
+{% endfor %}
+
+# HELP disk_used_size Disk used size in bytes
+# TYPE disk_used_size gauge
+{% for disk in system_info.disks %}
+disk_used_size{name="{{disk.name}}", mount_point="{{disk.mount_point}}"} {{disk.total_size - disk.free_size}}
+{% endfor %}
+
+# HELP disk_usage_percentage Disk usage percentage
+# TYPE disk_usage_percentage gauge
+{% for disk in system_info.disks %}
+disk_usage_percentage{name="{{disk.name}}", mount_point="{{disk.mount_point}}"} {% if disk.total_size > 0 %}{{(disk.total_size - disk.free_size) as f64 / disk.total_size as f64 * 100.0}}{% else %}0{% endif %}
+{% endfor %}