Redirect to Go package docs from a real browser, for certain repos (k…

…native#4524)

golang/_redirects

@@ -60,13 +60,14 @@
 /networking/* go-get=1 /golang/networking.html 200
 /operator/* go-get=1 /golang/operator.html 200
 /pkg/* go-get=1 /golang/pkg.html 200
+/pkg/* https://pkg.go.dev/knative.dev/pkg/:splat
 /reconciler-test/* go-get=1 /golang/reconciler-test.html 200
 /release/* go-get=1 /golang/release.html 200
 /sample-controller/* go-get=1 /golang/sample-controller.html 200
 /sample-source/* go-get=1 /golang/sample-source.html 200
 /serving/* go-get=1 /golang/serving.html 200
+/serving/* https://pkg.go.dev/knative.dev/serving/:splat
 /specs/* go-get=1 /golang/specs.html 200
 /test-infra/* go-get=1 /golang/test-infra.html 200
 /ux/* go-get=1 /golang/ux.html 200
-/website/* go-get=1 /golang/website.html 200
 /wg-repository/* go-get=1 /golang/wg-repository.html 200

tools/redir-gen/main.go

@@ -29,6 +29,11 @@ var (
 	knativeOrgs        = []string{"knative", "knative-sandbox"}
 	allowedRepoRe      = regexp.MustCompile("^[a-z][-a-z0-9]+$")
 	archivedExceptions = []string{"eventing-contrib"}
+
+	// Repos known to contain Go libraries, so that requesting
+	// https://knative.dev/<repo> in a browser should redirect to
+	// https://pkg.go.dev/knative.dev/<repo>
+	redirectingGoRepos = []string{"pkg", "serving"}
 )
 
 // repoInfo provides a simple holder for GitHub repo information needed to
@@ -102,6 +107,8 @@ const (
 `
 	redirText = `/{{.Repo}}/* go-get=1 /golang/{{.Repo}}.html 200
 `
+	godocRedirText = `/{{.Repo}}/* https://pkg.go.dev/knative.dev/{{.Repo}}/:splat
+`
 
 	autogenPrefix = `
 # This file is AUTO-GENERATED
@@ -125,15 +132,21 @@ func appendRedirs(ris []repoInfo) error {
 		return fmt.Errorf("unable to write to %q: %w", redirFilename, err)
 	}
 	for _, ri := range ris {
-		if redirTemplate.Execute(redirFile, ri) != nil {
+		if err := redirTemplate.Execute(redirFile, ri); err != nil {
 			return fmt.Errorf("unable to write %s to %q: %w", ri.Repo, redirFilename, err)
 		}
+		if isGoRepo(ri.Repo) {
+			if err := godocRedirTemplate.Execute(redirFile, ri); err != nil {
+				return fmt.Errorf("unable to write godoc redirect for %s to %q: %w", ri.Repo, redirFilename, err)
+			}
+		}
 	}
 	return nil
 }
 
 var fileTemplate = template.Must(template.New("gohtml").Parse(goHTML))
 var redirTemplate = template.Must(template.New("redir").Parse(redirText))
+var godocRedirTemplate = template.Must(template.New("redir").Parse(godocRedirText))
 
 // createGoGetFile creates a static HTML file providing a knative.dev mapping
 // for the specified org and repo.
@@ -171,3 +184,12 @@ func inArchivedExceptions(n string) bool {
 	}
 	return false
 }
+
+func isGoRepo(n string) bool {
+	for _, r := range redirectingGoRepos {
+		if r == n {
+			return true
+		}
+	}
+	return false
+}