feat: display database size on frontend via /stats endpoint

Author: jackharrhy

src/where_the_plow/db.py

@@ -1,4 +1,6 @@
 # src/where_the_plow/db.py
+import os
+
 import duckdb
 from datetime import datetime
 from itertools import groupby
@@ -301,10 +303,15 @@ def get_stats(self) -> dict:
         active_vehicles = self.conn.execute(
             "SELECT count(DISTINCT vehicle_id) FROM positions WHERE is_driving = 'maybe'"
         ).fetchone()[0]
+        try:
+            db_size_bytes = os.path.getsize(self.path)
+        except OSError:
+            db_size_bytes = None
         result = {
             "total_positions": total_positions,
             "total_vehicles": total_vehicles,
             "active_vehicles": active_vehicles,
+            "db_size_bytes": db_size_bytes,
         }
         if total_positions > 0:
             row = self.conn.execute(

src/where_the_plow/models.py

@@ -88,3 +88,4 @@ class StatsResponse(BaseModel):
     )
     earliest: str | None = Field(None, description="Earliest position timestamp")
     latest: str | None = Field(None, description="Latest position timestamp")
+    db_size_bytes: int | None = Field(None, description="Database file size in bytes")

src/where_the_plow/routes.py

@@ -202,4 +202,5 @@ def get_stats(request: Request):
         active_vehicles=stats.get("active_vehicles", 0),
         earliest=earliest.isoformat() if earliest else None,
         latest=latest.isoformat() if latest else None,
+        db_size_bytes=stats.get("db_size_bytes"),
     )

src/where_the_plow/static/index.html

@@ -50,6 +50,10 @@
       font-size: 12px;
       margin-top: 6px;
     }
+    #db-size {
+      color: #9ca3af;
+      font-size: 12px;
+    }
     #vehicle-detail {
       margin-top: 10px;
       padding-top: 10px;
@@ -164,6 +168,7 @@ <h3>Where the Plow</h3>
       <button id="btn-coverage">Coverage</button>
     </div>
     <div id="vehicle-count">Loading vehicles...</div>
+    <div id="db-size"></div>
     <div id="vehicle-detail">
       <span class="detail-close" id="detail-close">&times;</span>
       <div class="detail-name" id="detail-name"></div>
@@ -214,10 +219,24 @@ <h3>Where the Plow</h3>
       return VEHICLE_COLORS[type] || DEFAULT_COLOR;
     }
 
+    function formatBytes(bytes) {
+      if (bytes === null || bytes === undefined) return '';
+      if (bytes < 1024) return bytes + ' B';
+      if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(1) + ' KB';
+      if (bytes < 1024 * 1024 * 1024) return (bytes / (1024 * 1024)).toFixed(1) + ' MB';
+      return (bytes / (1024 * 1024 * 1024)).toFixed(1) + ' GB';
+    }
+
     function updateVehicleCount(data) {
       const count = data.features ? data.features.length : 0;
       document.getElementById('vehicle-count').textContent =
         count + ' vehicle' + (count !== 1 ? 's' : '') + ' tracked';
+      fetch('/stats').then(r => r.json()).then(stats => {
+        if (stats.db_size_bytes) {
+          document.getElementById('db-size').textContent =
+            formatBytes(stats.db_size_bytes) + ' of data';
+        }
+      }).catch(() => {});
     }
 
     async function fetchVehicles() {
@@ -464,6 +483,7 @@ <h3>Where the Plow</h3>
         map.setLayoutProperty('vehicle-circles', 'visibility', 'visible');
       }
       document.getElementById('vehicle-count').style.display = '';
+      document.getElementById('db-size').style.display = '';
       startAutoRefresh();
     }
 
@@ -477,6 +497,7 @@ <h3>Where the Plow</h3>
         map.setLayoutProperty('vehicle-circles', 'visibility', 'none');
       }
       document.getElementById('vehicle-count').style.display = 'none';
+      document.getElementById('db-size').style.display = 'none';
       coveragePanelEl.style.display = 'block';
       coverageLoading.style.display = 'block';
       timeSlider.value = 1000;

tests/test_db.py

@@ -192,6 +192,8 @@ def test_get_stats_empty():
     stats = db.get_stats()
     assert stats["total_positions"] == 0
     assert stats["total_vehicles"] == 0
+    assert stats["db_size_bytes"] is not None
+    assert stats["db_size_bytes"] > 0
     db.close()
     os.unlink(path)
 

tests/test_routes.py

@@ -177,6 +177,9 @@ def test_get_stats(test_client):
     data = resp.json()
     assert data["total_positions"] == 4
     assert data["total_vehicles"] == 2
+    assert "db_size_bytes" in data
+    assert data["db_size_bytes"] is not None
+    assert data["db_size_bytes"] > 0
 
 
 def test_openapi_spec(test_client):