feat: add metrics export as CSV/JSON (MON-04)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/archipelago/src/api/rpc/mod.rs

@@ -440,6 +440,7 @@ impl RpcHandler {
             "monitoring.alert-rules" => self.handle_monitoring_alert_rules().await,
             "monitoring.configure-alert" => self.handle_monitoring_configure_alert(params).await,
             "monitoring.acknowledge-alert" => self.handle_monitoring_acknowledge_alert(params).await,
+            "monitoring.export" => self.handle_monitoring_export(params).await,
 
             // System updates
             "update.check" => self.handle_update_check().await,

core/archipelago/src/api/rpc/monitoring.rs

@@ -116,6 +116,80 @@ impl RpcHandler {
         Ok(serde_json::json!({ "updated": true, "kind": kind_str }))
     }
 
+    /// monitoring.export — export metrics as CSV or JSON
+    pub(super) async fn handle_monitoring_export(
+        &self,
+        params: Option<serde_json::Value>,
+    ) -> Result<serde_json::Value> {
+        debug!("Exporting metrics");
+
+        let format = params
+            .as_ref()
+            .and_then(|p| p.get("format"))
+            .and_then(|v| v.as_str())
+            .unwrap_or("csv");
+
+        let resolution = params
+            .as_ref()
+            .and_then(|p| p.get("resolution"))
+            .and_then(|v| v.as_str())
+            .unwrap_or("minute");
+
+        let count = params
+            .as_ref()
+            .and_then(|p| p.get("count"))
+            .and_then(|v| v.as_u64())
+            .unwrap_or(1440) as usize;
+
+        let count = count.min(1440);
+
+        let data = match resolution {
+            "quarter_hour" | "15min" => self.metrics_store.history_quarter_hours(count).await,
+            _ => self.metrics_store.history_minutes(count).await,
+        };
+
+        match format {
+            "json" => {
+                Ok(serde_json::json!({
+                    "format": "json",
+                    "resolution": resolution,
+                    "count": data.len(),
+                    "data": data,
+                }))
+            }
+            _ => {
+                // CSV format
+                let mut csv = String::from(
+                    "timestamp,cpu_percent,mem_used_bytes,mem_total_bytes,disk_used_bytes,disk_total_bytes,net_rx_bytes,net_tx_bytes,load_avg_1,load_avg_5,load_avg_15,rpc_latency_ms,ws_connections\n"
+                );
+                for snapshot in &data {
+                    csv.push_str(&format!(
+                        "{},{:.1},{},{},{},{},{},{},{:.2},{:.2},{:.2},{:.1},{}\n",
+                        snapshot.timestamp,
+                        snapshot.system.cpu_percent,
+                        snapshot.system.mem_used_bytes,
+                        snapshot.system.mem_total_bytes,
+                        snapshot.system.disk_used_bytes,
+                        snapshot.system.disk_total_bytes,
+                        snapshot.system.net_rx_bytes,
+                        snapshot.system.net_tx_bytes,
+                        snapshot.system.load_avg_1,
+                        snapshot.system.load_avg_5,
+                        snapshot.system.load_avg_15,
+                        snapshot.rpc_latency_ms,
+                        snapshot.ws_connections,
+                    ));
+                }
+                Ok(serde_json::json!({
+                    "format": "csv",
+                    "resolution": resolution,
+                    "count": data.len(),
+                    "csv": csv,
+                }))
+            }
+        }
+    }
+
     /// monitoring.acknowledge-alert — acknowledge a fired alert
     pub(super) async fn handle_monitoring_acknowledge_alert(
         &self,