sendreports, sendalerts: and avoid db access while rendering templates--template renderer swallows any exceptions

sendreports: use select_related() to avoid doing N queries

hc/accounts/models.py

@@ -144,7 +144,11 @@ class Profile(models.Model):
 
         # Sort checks by owner. Need this because will group by owner in
         # template.
+        checks = checks.select_related("user", "user__profile")
         checks = checks.order_by("user_id")
+        # list() executes the query, to avoid DB access while
+        # rendering the template
+        checks = list(checks)
 
         ctx = {
             "checks": checks,

hc/api/transports.py

@@ -60,9 +60,11 @@ class Email(Transport):
             # Default sort order is by check's creation time
             sort = "created"
 
+        # list() executes the query, to avoid DB access while
+        # rendering a template
         ctx = {
             "check": check,
-            "checks": self.checks(),
+            "checks": list(self.checks()),
             "sort": sort,
             "now": timezone.now(),
             "unsub_link": self.channel.get_unsub_link()
@@ -288,9 +290,12 @@ class Pushover(HttpTransport):
 
     def notify(self, check):
         others = self.checks().filter(status="down").exclude(code=check.code)
+
+        # list() executes the query, to avoid DB access while
+        # rendering a template
         ctx = {
             "check": check,
-            "down_checks": others,
+            "down_checks": list(others),
         }
         text = tmpl("pushover_message.html", **ctx)
         title = tmpl("pushover_title.html", **ctx)