Allow using base64 encoded string to parsing customized logo files

Currently using svg file content for customized logo might break helm
format checking as Go doesn't know how to parse it.
This patch propose allow using base64 string to parse logo file.
Now we can use like below to avoid format issue:
  logo: "{{ lookup('file', inventory_dir ~ '/files/logo.svg') | b64encode }}"

And parse base64 format string is way more Go/helm friendly.

Change-Id: I2c35502e0592e1d1f6b3b10a5d6350e1fb78f53b

horizon/Chart.yaml

@@ -14,7 +14,7 @@ apiVersion: v1
 appVersion: v1.0.0
 description: OpenStack-Helm Horizon
 name: horizon
-version: 0.3.21
+version: 0.3.22
 home: https://docs.openstack.org/horizon/latest/
 icon: https://www.openstack.org/themes/openstack/images/project-mascots/Horizon/OpenStack_Project_Horizon_vertical.png
 sources:

horizon/templates/bin/_horizon.sh.tpl

@@ -90,9 +90,30 @@ function start () {
 
   # Copy custom logo images
   {{- if .Values.manifests.configmap_logo }}
-  cp /tmp/favicon.ico ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/favicon.ico
-  cp /tmp/logo.svg ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo.svg
-  cp /tmp/logo-splash.svg ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo-splash.svg
+  if [ -f /tmp/favicon.ico ]; then
+    favicon=$(cat /tmp/favicon.ico)
+    if [[ "$favicon" =~ ^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)?$ ]]; then
+      echo $(echo $favicon | base64 --decode) > ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/favicon.ico
+    else
+      cp /tmp/favicon.ico ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/favicon.ico
+    fi
+  fi
+  if [ -f /tmp/logo-splash.svg ]; then
+    logo_splash=$(cat /tmp/logo-splash.svg)
+    if [[ "$logo_splash" =~ ^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)?$ ]]; then
+      echo $(echo $logo_splash | base64 --decode) > ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo-splash.svg
+    else
+      cp /tmp/logo-splash.svg ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo-splash.svg
+    fi
+  fi
+  if [ -f /tmp/logo.svg ]; then
+    logo=$(cat /tmp/logo.svg)
+    if [[ "$logo" =~ ^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)?$ ]]; then
+      echo $(echo $logo | base64 --decode) > ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo.svg
+    else
+      cp /tmp/logo.svg ${SITE_PACKAGES_ROOT}/openstack_dashboard/static/dashboard/img/logo.svg
+    fi
+  fi
   {{- end }}
 
   # Compress Horizon's assets.

horizon/values.yaml

@@ -78,6 +78,7 @@ conf:
         - status
   horizon:
     branding:
+      # logo, logo_splash and favicon accepts base64 encoded string.
       logo:
       logo_splash:
       favicon:

releasenotes/notes/horizon.yaml

@@ -58,4 +58,5 @@ horizon:
   - 0.3.19 Add 2024.1 overrides
   - 0.3.20 Enable custom annotations for Openstack secrets
   - 0.3.21 Update images used by default
+  - 0.3.21 Allow using base64 str for parsing logo file
 ...