feat(algolia): add facets based on version for search

[haarchri]

When browsing older documentation versions (for example, v1.20), search results currently all content from latest....
This leads to confusion when users discover features or APIs in search results that don’t actually exist in the version they’re viewing.

This PR introduces version-aware search filtering using Algolia facet filters. https://www.algolia.com/doc/guides/managing-results/refine-results/faceting
Search results will be restricted to the documentation version the user is currently viewing.

• Added logic to detect the current page version via .Page.Params.version.
• Configured DocSearch to apply a facetFilters value dynamically:

['version:X.XX']

• Added special handling for the master version - uses version:0.0.0-master, which matches the existing meta tag convention where master is labeled 0.0.0-master to keep it de-ranked in search

Background

Each page already includes:

which the Algolia crawler indexes.

curl https://docs.crossplane.io/v2.0/composition/  | grep -A 10 "docsearch"
<meta name=docsearch:modified content='August 14, 2025'><meta name=docsearch:version content="2.0">

curl https://docs.crossplane.io/v1.20/concepts/  | grep -A 10 "docsearch"
<meta name=docsearch:modified content='May 21, 2025'><meta name=docsearch:version content="1.20">

Required: Algolia configuration

After this PR is merged, someone with Algolia admin access must enable faceting:

• Open Algolia Dashboard

• Go to the crossplane index

• Navigate to Configuration → Facets

• Add:
  searchable(version)
  to Attributes for faceting

• Save

Testing:

curl http://localhost:1313/v2.1/composition/ | grep -A 10 "docsearch"
...
<script>
    docsearch({
    container: '#docSearch',
    appId: 'xxx',
    indexName: 'crossplane',
    apiKey: 'xxxxx',
    placeholder: 'Search the docs',
    searchParameters: {
      facetFilters: ['version:2.1']
    }
    });
</script>

To verify this PR:

• Open any versioned docs page (for example, /v1.20/concepts/providers/)
• Open DevTools → Network
• Perform a search
• Inspect the request to algolia.net

{"requests":[{"query":"t","indexName":"crossplane","attributesToRetrieve":["hierarchy.lvl0","hierarchy.lvl1","hierarchy.lvl2","hierarchy.lvl3","hierarchy.lvl4","hierarchy.lvl5","hierarchy.lvl6","content","type","url"],"attributesToSnippet":["hierarchy.lvl1:10","hierarchy.lvl2:10","hierarchy.lvl3:10","hierarchy.lvl4:10","hierarchy.lvl5:10","hierarchy.lvl6:10","content:10"],"snippetEllipsisText":"…","highlightPreTag":"<mark>","highlightPostTag":"</mark>","hitsPerPage":20,"clickAnalytics":false,"facetFilters":["version:2.0"]}]}

we see the facetFilters

Fixes: #1008

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[jbw976]

This is very interesting @haarchri! Hopefully everything works smoothly after this PR gets merged 😂

One immediate question for you - do you know what the UX is going to be for showing multiple versions in the search? will the search popup make it clear which version each result is from? Will it favor newer versions over older versions? are you able to see this in your local testing, or do we have to merge this, update Algolia config, and see what happens?

[jbw976]

RE: the Algolia config instructions

Add:
filterOnly(docsearch:version)
to Attributes for faceting

Looks like we have a version attribute for faceting already on https://dashboard.algolia.com/apps/9UXKYX61NK/explorer/configuration/crossplane/facets, is that useful?

I was able to do a network inspect on the preview site and when searching it does look like facetFilters are being sent in the request, so that's a good sign 😉

facetFilters=%5B%22docsearch%3Aversion%3A0.0.0-master%22%5D

[haarchri]

@jbw976 the facet needs to match the tagName ... can you add docsearch:version ? its fine to do this before i guess - if we have an issue we can remove it

[jbw976]

added docsearch:version to attributes for faceting as "filter only" and saved it @haarchri!

[jbw976]

do you know what the UX is going to be for showing multiple versions in the search?

and i think the answer to this is that we don't show multiple versions in the results - we only show results for the version you're currently on. is that right @haarchri?

[jbw976]

by the way, trying to also make sense of this comment in the the netlify_build.sh:

# Search indexing only points to /latest, this prevents broken or out of date
# search results

is this configured somewhere in this docs repo that we need to update? on the algolia side? i haven't found it yet 😇

edit: ah, i think it's controlled by the sitemap.xml: https://docs.crossplane.io/sitemap.xml, which is generated from https://github.com/crossplane/docs/blob/master/themes/geekboot/layouts/_default/sitemap.xml.

Algolia doesn't appear to be configured to only look at latest, our sitemap/canonical/permalinks/etc. make it so any search engine (including Algolia) will only look at /latest and /contribute.

So i think we'd have to update that logic in this PR also for Algolia to start indexing those? If so, does that mean that google etc. will start indexing old versions too? we probably don't want old versions showing up in google results, only having /latest there is probably the right thing to do.

this is starting to get confusing, what do you think @haarchri? 😂