From 83aedc847784ba730f872c77849797c49400dd16 Mon Sep 17 00:00:00 2001
From: jmeridth <jmeridth@gmail.com>
Date: Sat, 30 May 2026 00:35:04 -0500
Subject: [PATCH] feat: add Google Analytics 4 (GA4) measurement tag
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Closes #78

## What

Add a GA4 measurement tag wired through `_config.yml`. The measurement ID `G-6DK8Y2SBT2` is set in `_config.yml` as `google_analytics_id`. `_includes/footer.html` emits the standard gtag.js snippet only when both conditions hold: `jekyll.environment == "production"` and `site.google_analytics_id` is set.

## Why

PR #79 removed the dead `UA-1265430-2` tag because Universal Analytics was sunset by Google on July 1, 2023 and was collecting no data. This PR re-introduces analytics on the modern GA4 platform under a new property. Putting the measurement ID in `_config.yml` keeps future ID changes out of template HTML. The `jekyll.environment == "production"` guard prevents local `jekyll serve` runs from polluting GA4 — GitHub Pages sets `JEKYLL_ENV=production` automatically during deploy builds, so production traffic is captured without needing manual configuration on the server side.

## Notes

- GA4 sets cookies and processes visitor IPs. For EU visitors this technically requires a cookie consent banner for GDPR compliance. Adding consent is out of scope for this PR; can be filed as a follow-up if the audience or legal posture changes.
- The snippet is gated on both the environment AND the config key being set, so removing `google_analytics_id` from `_config.yml` cleanly disables analytics without touching template code.
- The Liquid key `google_analytics_id` uses an underscore to match Jekyll's convention for templated variable names (`site.google_analytics_id`).

Signed-off-by: jmeridth <jmeridth@gmail.com>
---
 _config.yml           |  1 +
 _includes/footer.html | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/_config.yml b/_config.yml
index 7ec610cc..a0d1e417 100644
--- a/_config.yml
+++ b/_config.yml
@@ -29,6 +29,7 @@ twitter_username: lostechies
 github_username:  lostechies
 #permalink: /:collection/:year/:month/:day/:title/
 rss2json_api_key: "8rtxarjik93svbgojealqe4pzyta8qjzhcdhy40d"
+google_analytics_id: "G-6DK8Y2SBT2"
 
 # Only supported by > Jekyll 3.7.0
 #collections_dir: posts
diff --git a/_includes/footer.html b/_includes/footer.html
index 9a69c494..11625ba4 100644
--- a/_includes/footer.html
+++ b/_includes/footer.html
@@ -20,3 +20,14 @@
 <script src="{{ site.baseurl }}/assets/js/feed.js"></script>
 <script src="{{ site.baseurl }}/assets/js/load-authors.js"></script>
 <script src="{{ site.baseurl }}/assets/js/load-recent-posts.js"></script>
+
+{% if jekyll.environment == "production" and site.google_analytics_id %}
+<!-- Google tag (gtag.js) -->
+<script async src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics_id }}"></script>
+<script>
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+  gtag('config', '{{ site.google_analytics_id }}');
+</script>
+{% endif %}