hugo: define front matter metadata through data

Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

data/frontmatter.yaml

@@ -0,0 +1,10 @@
+# this file lets you add descriptions and keywords
+# to files without modifying the file.
+#
+# Useful for upstream pages where we don't want to
+# or can't add front matter to the source!
+#
+# To add descriptions and keywords for a page,
+# add a key with the path of the page file,
+# relative to the content directory. For upstream
+# page files, that's the target of the file mount.

layouts/partials/meta.html

@@ -1,5 +1,5 @@
 {{ $title := partial "utils/title.html" . }}
-{{ $description := .Description | default .Summary }}
+{{ $description := partial "utils/description.html" . }}
 {{ if .IsHome }}
   <title>{{ site.Title }}</title>
 {{ else }}
@@ -13,7 +13,7 @@
 <meta name="description" content="{{ $description }}" />
 <meta
   name="keywords"
-  content="{{ .Keywords | default "docker, docker open source, docker platform, distributed applications, microservices, containers, docker containers, docker software, docker virtualization" }}"
+  content="{{- partial "utils/keywords.html" . -}}"
 />
 <link rel="canonical" href="{{ .Permalink }}" />
 

layouts/partials/utils/description.html

@@ -0,0 +1,14 @@
+{{ $desc := "" }}
+{{ if .Description }}
+  {{ $desc = .Description }}
+{{ else }}
+  {{ $desc = .Summary }}
+  {{ with .File }}
+    {{ with (index (site.Data.frontmatter) .Path) }}
+      {{ with .description }}
+        {{ $desc = strings.Replace . "\n" " " | strings.TrimRight " " }}
+      {{ end }}
+    {{ end }}
+  {{ end }}
+{{ end }}
+{{ return $desc }}

layouts/partials/utils/keywords.html

@@ -0,0 +1,14 @@
+{{ $keywords := "" }}
+{{ if .Keywords }}
+  {{ $keywords = .Keywords }}
+{{ else }}
+  {{ $keywords = "docker, docker open source, docker platform, distributed applications, microservices, containers, docker containers, docker software, docker virtualization" }}
+  {{ with .File }}
+    {{ with (index (site.Data.frontmatter) .Path) }}
+      {{ with .keywords }}
+        {{ $keywords = strings.Replace . "\n" " " | strings.TrimRight " " }}
+      {{ end }}
+    {{ end }}
+  {{ end }}
+{{ end }}
+{{ return $keywords }}

layouts/partials/utils/title.html

@@ -3,8 +3,13 @@
   {{ $title = .LinkTitle }}
 {{ else }}
   {{ $title = index (findRE `# .*` .RawContent) 0 | strings.TrimLeft "# " }}
-  {{ if not $title }}
+  {{ with .File }}
-    {{ with .File }}
+    {{ with (index (site.Data.frontmatter) .Path) }}
+      {{ with .title }}
+        {{ $title = . }}
+      {{ end }}
+    {{ end }}
+    {{ if not $title }}
       {{ $title = strings.ReplaceRE "[-_]" " " .TranslationBaseName }}
     {{ end }}
   {{ end }}