fix: have diagnostics endpoint always return a string for hmetric

Previously the diagnositcs endpoint would return either a string or number for hmetric. The agent always assumed it was a string. We have not ran into this previously due to cluster_stats being somewhat broken and would always returns string. But now that has been fixedwith 79a29b3 and e139053 it can now return a number which was breaking the agent. This change makes it that hmetric is always a string. Due to this, we also move the 'Unknown health' prefix if there are no requests yet to envoy_stats.py instead if in the diag jinja template.

Signed-off-by: Hamzah Qudsi <hqudsi@datawire.io>

python/ambassador/diagnostics/envoy_stats.py

@@ -130,9 +130,15 @@ def cluster_stats(self, name: str) -> Dict[str, Union[str, bool]]:
             elif pct < 90:
                 color = "yellow"
 
-            cstat.update({"health": "%d%% healthy" % pct, "hmetric": int(pct), "hcolor": color})
+            cstat.update({"health": "%d%% healthy" % pct, "hmetric": str(pct), "hcolor": color})
         else:
-            cstat.update({"health": "no requests yet", "hmetric": "waiting", "hcolor": "grey"})
+            cstat.update(
+                {
+                    "health": "Unknown health: no requests yet",
+                    "hmetric": "waiting",
+                    "hcolor": "grey",
+                }
+            )
 
         return cstat
 

python/templates/diag.html

@@ -166,7 +166,6 @@ <h1 style="color: red; text-align: right">DEBUG MODE</h1>
                   <br/><br/>
                   <span style="color:{{ cluster._hcolor }}">
                     {% if cluster_stats[cluster.name].valid %}
-                      {{ 'Unknown health: ' if cluster._hmetric is not number }}
                       {{ cluster._health }}
                     {% else %}
                       Unknown health: {{ cluster_stats[cluster.name].reason }}