fix(docker): configure Prometheus external URL for HF Spaces

docker/scripts/start_space.sh

@@ -71,13 +71,21 @@ scrape_configs:
       - targets: ['127.0.0.1:9090']
 EOF
 
+# Determine Prometheus External URL
+if [ -n "$SPACE_ID" ]; then
+    PROM_EXTERNAL_URL="https://huggingface.co/spaces/$SPACE_ID/prometheus/"
+else
+    PROM_EXTERNAL_URL="/prometheus/"
+fi
+
 # Start Prometheus
-# --web.external-url needs to match the path in Nginx
+# --web.external-url needs to match the public URL for correct link generation
+# --web.route-prefix needs to match the path Nginx proxies to (/prometheus/)
 prometheus \
     --config.file=/tmp/prometheus.yml \
     --storage.tsdb.path=/tmp/prometheus_data \
     --web.listen-address=0.0.0.0:9090 \
-    --web.external-url=/prometheus/ \
+    --web.external-url=$PROM_EXTERNAL_URL \
     --web.route-prefix=/prometheus/ \
     >> /tmp/prometheus.log 2>&1 &