feat(guard): add posthog integration (#597)

## 📝 Description
Adds posthog integration to login/signup pages in the guard service.

## ✅ Checklist
- [x] I have tested this change
- [ ] This change requires documentation update

Author: skipi

guard/config/config.exs

@@ -126,4 +126,7 @@ config :guard, Guard.OrganizationCleaner,
 
 config :guard, :hard_destroy_grace_period_days, 30
 
+config :guard, :posthog_api_key, ""
+config :guard, :posthog_host, "https://app.posthog.com"
+
 import_config "#{config_env()}.exs"

guard/config/runtime.exs

@@ -166,6 +166,9 @@ config :guard,
        :hide_gitlab_login_page,
        System.get_env("HIDE_GITLAB_LOGIN_PAGE") == "true"
 
+config :guard, :posthog_api_key, System.get_env("POSTHOG_API_KEY")
+config :guard, :posthog_host, System.get_env("POSTHOG_HOST") || "https://app.posthog.com"
+
 if System.get_env("AMQP_URL") != nil do
   config :amqp,
     connections: [

guard/lib/guard/id/api.ex

@@ -188,6 +188,12 @@ defmodule Guard.Id.Api do
   end
 
   defp render_signup_page(conn, assigns) do
+    assigns =
+      Keyword.merge(assigns,
+        posthog_api_key: Application.get_env(:guard, :posthog_api_key, ""),
+        posthog_host: Application.get_env(:guard, :posthog_host, "https://app.posthog.com")
+      )
+
     html_content = Guard.TemplateRenderer.render_template([assigns: assigns], "signup.html")
 
     conn
@@ -326,6 +332,12 @@ defmodule Guard.Id.Api do
   end
 
   defp render_login_page(conn, assigns) do
+    assigns =
+      Keyword.merge(assigns,
+        posthog_api_key: Application.get_env(:guard, :posthog_api_key, ""),
+        posthog_host: Application.get_env(:guard, :posthog_host, "https://app.posthog.com")
+      )
+
     html_content = Guard.TemplateRenderer.render_template([assigns: assigns], "login.html")
 
     conn

guard/templates/login.html.eex

@@ -41,6 +41,17 @@
       <meta name="twitter:data1" content="1 minute" />
       <meta name="twitter:label2" content="Written by" />
       <meta name="twitter:data2" content="Semaphore Team" />
+      <% if @assigns[:posthog_api_key] && @assigns[:posthog_api_key] != "" do %>
+      <script>
+        !function(t,e){var o,n,p,r;e.__SV||(window.posthog=e,e._i=[],e.init=function(i,s,a){function g(t,e){var o=e.split(".");2==o.length&&(t=t[o[0]],e=o[1]),t[e]=function(){t.push([e].concat(Array.prototype.slice.call(arguments,0)))}}(p=t.createElement("script")).type="text/javascript",p.crossOrigin="anonymous",p.async=!0,p.src=s.api_host.replace(".i.posthog.com","-assets.i.posthog.com")+"/static/array.js",(r=t.getElementsByTagName("script")[0]).parentNode.insertBefore(p,r);var u=e;for(void 0!==a?u=e[a]=[]:a="posthog",u.people=u.people||[],u.toString=function(t){var e="posthog";return"posthog"!==a&&(e+="."+a),t||(e+=" (stub)"),e},u.people.toString=function(){return u.toString(1)+".people (stub)"},o="init Ce js Ls Te Fs Ds capture Ye calculateEventProperties Us register register_once register_for_session unregister unregister_for_session Ws getFeatureFlag getFeatureFlagPayload isFeatureEnabled reloadFeatureFlags updateEarlyAccessFeatureEnrollment getEarlyAccessFeatures on onFeatureFlags onSurveysLoaded onSessionId getSurveys getActiveMatchingSurveys renderSurvey displaySurvey canRenderSurvey canRenderSurveyAsync identify setPersonProperties group resetGroups setPersonPropertiesForFlags resetPersonPropertiesForFlags setGroupPropertiesForFlags resetGroupPropertiesForFlags reset get_distinct_id getGroups get_session_id get_session_replay_url alias set_config startSessionRecording stopSessionRecording sessionRecordingStarted captureException loadToolbar get_property getSessionProperty Bs zs createPersonProfile Hs Ms Gs opt_in_capturing opt_out_capturing has_opted_in_capturing has_opted_out_capturing get_explicit_consent_status is_capturing clear_opt_in_out_capturing Ns debug L qs getPageViewId captureTraceFeedback captureTraceMetric".split(" "),n=0;n<o.length;n++)g(u,o[n]);e._i.push([i,s,a])},e.__SV=1)}(document,window.posthog||[]);
+
+        posthog.init('<%= @assigns[:posthog_api_key] %>', {
+          api_host: '<%= @assigns[:posthog_host] %>',
+          defaults: '2025-05-24',
+          person_profiles: 'identified_only'
+        });
+      </script>
+      <% end %>
    </head>
    <body class="page-template-default page page-id-19406 wp-embed-responsive no-sidebar">
       <div id="page" class="site no-header-no-footer green   v8theme ">

guard/templates/signup.html.eex

@@ -44,6 +44,17 @@
     <meta name="twitter:data1" content="1 minute">
     <meta name="twitter:label2" content="Written by">
     <meta name="twitter:data2" content="Semaphore Team">
+    <% if @assigns[:posthog_api_key] && @assigns[:posthog_api_key] != "" do %>
+    <script>
+      !function(t,e){var o,n,p,r;e.__SV||(window.posthog=e,e._i=[],e.init=function(i,s,a){function g(t,e){var o=e.split(".");2==o.length&&(t=t[o[0]],e=o[1]),t[e]=function(){t.push([e].concat(Array.prototype.slice.call(arguments,0)))}}(p=t.createElement("script")).type="text/javascript",p.crossOrigin="anonymous",p.async=!0,p.src=s.api_host.replace(".i.posthog.com","-assets.i.posthog.com")+"/static/array.js",(r=t.getElementsByTagName("script")[0]).parentNode.insertBefore(p,r);var u=e;for(void 0!==a?u=e[a]=[]:a="posthog",u.people=u.people||[],u.toString=function(t){var e="posthog";return"posthog"!==a&&(e+="."+a),t||(e+=" (stub)"),e},u.people.toString=function(){return u.toString(1)+".people (stub)"},o="init Ce js Ls Te Fs Ds capture Ye calculateEventProperties Us register register_once register_for_session unregister unregister_for_session Ws getFeatureFlag getFeatureFlagPayload isFeatureEnabled reloadFeatureFlags updateEarlyAccessFeatureEnrollment getEarlyAccessFeatures on onFeatureFlags onSurveysLoaded onSessionId getSurveys getActiveMatchingSurveys renderSurvey displaySurvey canRenderSurvey canRenderSurveyAsync identify setPersonProperties group resetGroups setPersonPropertiesForFlags resetPersonPropertiesForFlags setGroupPropertiesForFlags resetGroupPropertiesForFlags reset get_distinct_id getGroups get_session_id get_session_replay_url alias set_config startSessionRecording stopSessionRecording sessionRecordingStarted captureException loadToolbar get_property getSessionProperty Bs zs createPersonProfile Hs Ms Gs opt_in_capturing opt_out_capturing has_opted_in_capturing has_opted_out_capturing get_explicit_consent_status is_capturing clear_opt_in_out_capturing Ns debug L qs getPageViewId captureTraceFeedback captureTraceMetric".split(" "),n=0;n<o.length;n++)g(u,o[n]);e._i.push([i,s,a])},e.__SV=1)}(document,window.posthog||[]);
+
+      posthog.init('<%= @assigns[:posthog_api_key] %>', {
+        api_host: '<%= @assigns[:posthog_host] %>',
+        defaults: '2025-05-24',
+        person_profiles: 'identified_only'
+      });
+    </script>
+    <% end %>
   </head>
   <body class="page-template-default page page-id-19406 wp-embed-responsive no-sidebar">
     <header>