Add total torrent size metric and dashboard panel

- Query torrent-get RPC to sum totalSize of all torrents
- Add transmission_torrents_size_bytes gauge metric
- Add "Total Torrent Size" timeseries panel to dashboard

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ansible/roles/grafana/files/dashboards/transmission.json

@@ -571,6 +571,86 @@
       ],
       "title": "Cumulative Transfer Rate (5m avg)",
       "type": "timeseries"
+    },
+    {
+      "datasource": {
+        "type": "prometheus",
+        "uid": "prometheus"
+      },
+      "fieldConfig": {
+        "defaults": {
+          "color": {
+            "mode": "fixed",
+            "fixedColor": "semi-dark-purple"
+          },
+          "custom": {
+            "axisBorderShow": false,
+            "axisCenteredZero": false,
+            "axisColorMode": "text",
+            "axisLabel": "",
+            "axisPlacement": "auto",
+            "barAlignment": 0,
+            "drawStyle": "line",
+            "fillOpacity": 20,
+            "gradientMode": "opacity",
+            "hideFrom": {
+              "legend": false,
+              "tooltip": false,
+              "viz": false
+            },
+            "insertNulls": false,
+            "lineInterpolation": "linear",
+            "lineWidth": 2,
+            "pointSize": 5,
+            "scaleDistribution": {
+              "type": "linear"
+            },
+            "showPoints": "never",
+            "spanNulls": false,
+            "stacking": {
+              "group": "A",
+              "mode": "none"
+            },
+            "thresholdsStyle": {
+              "mode": "off"
+            }
+          },
+          "mappings": [],
+          "thresholds": {
+            "mode": "absolute",
+            "steps": [
+              {"color": "green", "value": null}
+            ]
+          },
+          "unit": "decbytes"
+        },
+        "overrides": []
+      },
+      "gridPos": {"h": 8, "w": 24, "x": 0, "y": 20},
+      "id": 10,
+      "options": {
+        "legend": {
+          "calcs": ["lastNotNull", "min", "max"],
+          "displayMode": "table",
+          "placement": "right",
+          "showLegend": true
+        },
+        "tooltip": {
+          "mode": "single",
+          "sort": "none"
+        }
+      },
+      "pluginVersion": "10.0.0",
+      "targets": [
+        {
+          "datasource": {"type": "prometheus", "uid": "prometheus"},
+          "expr": "transmission_torrents_size_bytes",
+          "legendFormat": "Total Torrent Size",
+          "refId": "A"
+        }
+      ],
+      "title": "Total Torrent Size",
+      "type": "timeseries"
     }
   ],
   "refresh": "30s",

ansible/roles/transmission_metrics/templates/transmission-metrics.sh.j2

@@ -18,6 +18,7 @@ get_session_id() {
 # Make RPC request
 rpc_request() {
     local method="$1"
+    local args="${2:-}"
     local session_id
     session_id=$(get_session_id)
 
@@ -26,10 +27,17 @@ rpc_request() {
         return 1
     fi
 
+    local payload
+    if [ -n "$args" ]; then
+        payload="{\"method\": \"$method\", \"arguments\": $args}"
+    else
+        payload="{\"method\": \"$method\"}"
+    fi
+
     curl -s "$RPC_URL" \
         -H "X-Transmission-Session-Id: $session_id" \
         -H "Content-Type: application/json" \
-        -d "{\"method\": \"$method\"}"
+        -d "$payload"
 }
 
 # Get session stats
@@ -57,6 +65,14 @@ downloaded_bytes=$(echo "$session_stats" | grep -o '"cumulative-stats":{[^}]*}'
 uploaded_bytes=$(echo "$session_stats" | grep -o '"cumulative-stats":{[^}]*}' | grep -o '"uploadedBytes":[0-9]*' | sed 's/"uploadedBytes"://')
 seconds_active=$(echo "$session_stats" | grep -o '"cumulative-stats":{[^}]*}' | grep -o '"secondsActive":[0-9]*' | sed 's/"secondsActive"://')
 
+# Get total size of all torrents
+torrent_info=$(rpc_request "torrent-get" '{"fields": ["totalSize"]}')
+total_size_bytes=0
+if echo "$torrent_info" | grep -q '"result":"success"'; then
+    # Sum all totalSize values
+    total_size_bytes=$(echo "$torrent_info" | grep -o '"totalSize":[0-9]*' | sed 's/"totalSize"://' | awk '{sum += $1} END {print sum}')
+fi
+
 # Write metrics
 cat > "$TEMP_FILE" << EOF
 # HELP transmission_download_speed_bytes Current download speed in bytes per second
@@ -79,6 +95,10 @@ transmission_torrents_paused ${torrents_paused:-0}
 # TYPE transmission_torrents_total gauge
 transmission_torrents_total ${torrents_total:-0}
 
+# HELP transmission_torrents_size_bytes Total size of all torrents in bytes
+# TYPE transmission_torrents_size_bytes gauge
+transmission_torrents_size_bytes ${total_size_bytes:-0}
+
 # HELP transmission_downloaded_bytes_total Total bytes downloaded (cumulative)
 # TYPE transmission_downloaded_bytes_total counter
 transmission_downloaded_bytes_total ${downloaded_bytes:-0}