Create preStop sentinal file for web deployments (#774)

This allows us to start failing readiness checks when we are terminating
so we stop receiving new traffic but can gracefully finish existing
traffic

charts/posthog/Chart.yaml

@@ -11,7 +11,7 @@ type: application
 
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
-version: 30.30.0
+version: 30.31.0
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application.

charts/posthog/templates/_snippet-web-deployments.tpl

@@ -22,18 +22,18 @@ lifecycle:
         exec:
             command: [
                 "sh", "-c",
-                "(echo '{\"event\": \"preStop_started\"}'; sleep 10; echo '{\"event\": \"preStop_ended\"}') > /proc/1/fd/1"
+                "(echo '{\"event\": \"preStop_started\"}'; touch /tmp/posthog_prestop || true; sleep 20; echo '{\"event\": \"preStop_ended\"}') > /proc/1/fd/1"
             ]
 {{- end -}}
 
 
 {{/*
 
-    Set a grace period that is 10 seconds delay (from
+    Set a grace period that is 20 seconds delay (from
     lifecycle.exec.preStop) + 30 seconds for Gunicorn to gracefully shutdown
     + 5 seconds leeway
 
 */}}
 {{- define "snippet.web-deployments.terminationGracePeriodSeconds" -}}
-45
+55
 {{- end -}}

charts/posthog/tests/web-deployments.yaml

@@ -14,6 +14,6 @@ tests:
     asserts:
       - equal:
           path: spec.template.spec.terminationGracePeriodSeconds
-          value: 45
+          value: 55
       - isNotNull:
           path: spec.template.spec.containers[0].lifecycle