Kubernetes Green / Blue deployment with Helm

_helpers.tpl

{{/*
Create revion color "green" / "blue" from release number
*/}}
{{- define "project.revisioncolor" -}}
{{- if mod .Release.Revision 2 -}}
{{- printf "green" -}}
{{- else -}}
{{- printf "blue" -}}
{{- end -}}
{{- end -}}

deployment.yaml

spec:
  template:
    spec:
      containers:
        ...  
          env:
            - name: STATIC_PUBLISHING_DIRECTORY
              value: "{{ .Values.staticBasePath }}/{{ include "project.revisioncolor" . }}"