Fetch the pod's HOSTNAME via downward API and pass it as env.var

... when the pod is deployed as part of an StatefulSet, so it can
determine its identity on startup and pick the right config file
from the '*-configfiles' mount.

Author: SamuAlfageme

revad/templates/deployment.yaml

@@ -35,7 +35,7 @@ spec:
           args:
               - "-c"
               {{- if .Values.useStatefulSet }}
-              - "/etc/revad/${HOSTNAME}.toml"
+              - "/etc/revad/$(HOSTNAME).toml"
               {{- else }}
               - "/etc/revad/revad.toml"
               {{- end }}
@@ -50,8 +50,14 @@ spec:
             {{- if .Values.extraVolumeMounts }}
               {{ toYaml .Values.extraVolumeMounts | nindent 12 }}
             {{- end }}
-          {{- if or .Values.env .Values.extraEnv }}
+          {{- if or .Values.useStatefulSet (or .Values.env .Values.extraEnv) }}
           env:
+            {{- if .Values.useStatefulSet }}
+            - name: HOSTNAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: metadata.name
+            {{- end }}
           {{- range $name, $value := .Values.env }}
             - name: "{{ $name }}"
               value: "{{ $value }}"
@@ -63,7 +69,6 @@ spec:
           {{- if .Values.envFrom }}
           envFrom:
             {{ toYaml .Values.envFrom | indent 12 }}
-          {{- end }}
       volumes:
         - name: {{ include "revad.fullname" . }}-configfiles
           configMap:
@@ -84,7 +89,7 @@ spec:
         accessModes:
           {{- toYaml .Values.persistentVolume.accessModes | indent 10 }}
         resources:
-          requests: 
+          requests:
             storage: "{{ .Values.persistentVolume.size }}"
           {{- if (eq "-" .Values.persistentVolume.storageClass) }}
             storageClassName: ""