I went through a brief struggle figuring out how to generate sitemaps accepted by Google from my site built with Hugo and deployed on Netlify. Here’s how I fixed it.
The Problem
When publishing a Hugo site with Netlify, Netlify recommends setting the base URL to “/” . This appears to work great when you’re just browsing the site. Links resolve correctly in both the production build as well as any deploy previews even though the hostname changes.
When you take the next step with your site and start looking into SEO, you run into the issue of Google (among others) complaining that your sitemap contains invalid URLs. The issue is that they expect full URLs with a scheme, hostname, and path, and the recommended Hugo configuration results in links that are just absolute paths (no hostname or scheme).
The Solution
The solution is to specify your canonical production URL as the base URL in
hugo.toml. You can then add the following to netlify.toml to override the
base URL for deploy previews:
[context.deploy-preview]
command = "hugo --baseURL $DEPLOY_PRIME_URL"
In development, the hugo server command automatically overrides the base URL
to whatever localhost port the development server is bound to.
Why Not $DEPLOY_PRIME_URL Everywhere?
As stated by Netlify, $DEPLOY_PRIME_URL is a “URL representing the primary URL
for an individual deploy, or a group of them, like branch deploys and Deploy
Previews; for example, https://feature-branch--petsof.netlify.app or
https://deploy-preview-1--petsof.netlify.app”.
This is great for pointing to deploy previews, but for your primary production deployment, this would still point to the name of your main branch rather than any custom domain you have set up.