Only build last 3 versions of user-guide for staging (#4072)

* Only build last 3 versions of user-guide for staging

- To speed it up a bit
- Also remove sed'ing of docusaurus.config.js, read env vars instead

* actually export vars

.github/workflows/docs.yaml

@@ -44,9 +44,11 @@ jobs:
           else
           npm i
           fi
-          sed -i 's#url:.*$#url: "https://staging.docs.gitops.weave.works",#' docusaurus.config.js
-          sed -i "s#baseUrl:.*\$#baseUrl: \"/$GITHUB_HEAD_REF/\",#" docusaurus.config.js
           yarn clear
+
+          export DOC_BASE_URL="/$GITHUB_HEAD_REF/"
+          export DOC_URL=https://staging.docs.gitops.weave.works
+          export STAGING_BUILD=true
           npm run build
       - id: auth
         uses: google-github-actions/auth@35b0e87d162680511bf346c299f71c9c5c379033 # v1.1.1

website/docusaurus.config.js

@@ -3,8 +3,8 @@ const versions = require("./versions.json");
 module.exports = {
   title: "Weave GitOps",
   tagline: "The Flux expansion pack from the founders of Flux",
-  url: "https://docs.gitops.weave.works",
-  baseUrl: "/",
+  url: process.env.DOC_URL || "https://docs.gitops.weave.works",
+  baseUrl: process.env.DOC_BASE_URL || "/",
   onBrokenLinks: "throw",
   onBrokenMarkdownLinks: "warn",
   favicon: "img/favicon_150px.png",
@@ -187,6 +187,15 @@ module.exports = {
           id: 'default',
           sidebarPath: require.resolve("./sidebars.js"),
           editUrl: "https://github.com/weaveworks/weave-gitops/edit/main/website",
+          onlyIncludeVersions: (() => {
+            if (process.env.STAGING_BUILD === "true") {
+              // Build the last 3 versions for staging to speed it up a bit
+              return ["current", ...versions.slice(0, 3)];
+            }
+
+            // Return undefined which will fall back to the default of all versions
+            return undefined;
+          })(),
           disableVersioning: process.env.DISABLE_VERSIONING === "true",
         },
         blog: {