prom: Fix breakage due to msat purge

Closes #450

prometheus/prometheus.py

@@ -32,7 +32,11 @@ class NodeCollector(BaseLnCollector):
             value=blockheight,
         )
 
-        fees_msat = info["msatoshi_fees_collected"]
+        print(info)
+        fees_msat = int(info.get(
+            "fees_collected_msat",
+            info.get("msatoshi_fees_collected", None)
+        ))
         yield GaugeMetricFamily(
             'lightning_fees_collected_msat',
             'How much have we been paid to route payments?',

prometheus/test_prometheus.py

@@ -1,5 +1,6 @@
 import os
 from pyln.testing.fixtures import *  # noqa: F401,F403
+import urllib
 
 plugin_path = os.path.join(os.path.dirname(__file__), "prometheus.py")
 
@@ -14,3 +15,13 @@ def test_prometheus_starts(node_factory):
     # Then statically
     l1.daemon.opts["plugin"] = plugin_path
     l1.start()
+
+
+def test_prometheus_scrape(node_factory):
+    """Test that we can scrape correctly.
+    """
+    l1 = node_factory.get_node(options={'plugin': plugin_path})
+    scrape = urllib.request.urlopen("http://localhost:9750")
+    
+    
+