helm: render the mysql secret and env only for the mysql filer store (#10872)

The db credential secret and the filer's WEED_MYSQL_* env were gated on
filer.enabled alone, so a filer on mongodb, redis, postgres or leveldb2 got a
generated mysql secret it never reads - kept forever by resource-policy: keep -
plus a mysql-db-host pointing nowhere.

Gate all of it on WEED_MYSQL_ENABLED, which is how the store is selected, plain
keys and secret-backed ones alike. An enable flag the chart cannot read - a
valueFrom, or one in secretExtraEnvironmentVars - counts as selected, so nothing
is dropped from a filer that is actually on mysql.

k8s/charts/seaweedfs/README.md

@@ -22,8 +22,8 @@ helm install --values=values.yaml seaweedfs seaweedfs/seaweedfs
 ## Info:
 * master/filer/volume are stateful sets with anti-affinity on the hostname,
 so your deployment will be spread/HA.
-* chart is using memsql(mysql) as the filer backend to enable HA (multiple filer instances) and backup/HA memsql can provide.
-* mysql user/password are created in a k8s secret (default: `<release>-seaweedfs-db-secret`) and injected to the filer with ENV.
+* leveldb2 is the default filer backend; a mysql-compatible database (memsql, ...) enables HA (multiple filer instances) and the backup/HA it can provide.
+* with `filer.extraEnvironmentVars.WEED_MYSQL_ENABLED` set to `"true"`, mysql user/password are created in a k8s secret (default: `<release>-seaweedfs-db-secret`) and injected to the filer with ENV. On any other store neither the secret nor the `WEED_MYSQL_*` env, plain or secret-backed, is rendered.
 * cert config exists and can be enabled, but not been tested, requires cert-manager to be installed.
 
 ## Prerequisites

k8s/charts/seaweedfs/templates/filer/filer-statefulset.yaml

@@ -92,6 +92,7 @@ spec:
           image: {{ template "seaweedfs.filer.image" . }}
           imagePullPolicy: {{ default "IfNotPresent" .Values.global.seaweedfs.imagePullPolicy }}
           env:
+            {{- $mysqlEnabled := include "seaweedfs.filer.mysqlEnabled" . }}
             - name: POD_IP
               valueFrom:
                 fieldRef:
@@ -104,6 +105,7 @@ spec:
               valueFrom:
                 fieldRef:
                   fieldPath: metadata.namespace
+            {{- if $mysqlEnabled }}
             - name: WEED_MYSQL_USERNAME
               valueFrom:
                 secretKeyRef:
@@ -116,6 +118,7 @@ spec:
                   name: {{ include "seaweedfs.fullname" . }}-db-secret
                   key: password
                   optional: true
+            {{- end }}
             - name: SEAWEEDFS_FULLNAME
               value: "{{ include "seaweedfs.fullname" . }}"
             {{- if and .Values.filer.s3.enabled .Values.filer.s3.enableAuth }}
@@ -123,6 +126,13 @@ spec:
             {{- end }}
             {{- $mergedExtraEnvironmentVars := dict }}
             {{- include "seaweedfs.mergeExtraEnvironmentVars" (dict "global" .Values.global.seaweedfs "component" .Values.filer "target" $mergedExtraEnvironmentVars) }}
+            {{- if not $mysqlEnabled }}
+            {{- range $key := keys $mergedExtraEnvironmentVars }}
+            {{- if hasPrefix "WEED_MYSQL_" $key }}
+            {{- $_ := unset $mergedExtraEnvironmentVars $key }}
+            {{- end }}
+            {{- end }}
+            {{- end }}
             {{- range $key := keys $mergedExtraEnvironmentVars | sortAlpha }}
             {{- $value := index $mergedExtraEnvironmentVars $key }}
             - name: {{ $key }}
@@ -135,10 +145,12 @@ spec:
             {{- end }}
             {{- if .Values.filer.secretExtraEnvironmentVars }}
             {{- range $key, $value := .Values.filer.secretExtraEnvironmentVars }}
+            {{- if or $mysqlEnabled (not (hasPrefix "WEED_MYSQL_" $key)) }}
             - name: {{ $key }}
               valueFrom: {{ toYaml $value | nindent 16 }}
             {{- end }}
             {{- end }}
+            {{- end }}
           command:
             - "/bin/sh"
             - "-ec"

k8s/charts/seaweedfs/templates/shared/_helpers.tpl

@@ -76,6 +76,18 @@ Inject extra environment vars in the format key:value, if populated
 {{- end }}
 {{- end -}}
 
+{{/* Whether the mysql filer store is selected; a flag the chart cannot read counts as selected. */}}
+{{- define "seaweedfs.filer.mysqlEnabled" -}}
+{{- $merged := dict -}}
+{{- $_ := include "seaweedfs.mergeExtraEnvironmentVars" (dict "global" .Values.global.seaweedfs "component" .Values.filer "target" $merged) -}}
+{{- $enabled := index $merged "WEED_MYSQL_ENABLED" -}}
+{{- if or (kindIs "map" $enabled) (hasKey (.Values.filer.secretExtraEnvironmentVars | default dict) "WEED_MYSQL_ENABLED") -}}
+true
+{{- else if and $enabled (eq (lower (toString $enabled)) "true") -}}
+true
+{{- end -}}
+{{- end -}}
+
 {{/* Return the proper filer image */}}
 {{- define "seaweedfs.filer.image" -}}
 {{- if .Values.filer.imageOverride -}}

k8s/charts/seaweedfs/templates/shared/secret-seaweedfs-db.yaml

@@ -1,4 +1,4 @@
-{{- if .Values.filer.enabled }}
+{{- if and .Values.filer.enabled (include "seaweedfs.filer.mysqlEnabled" .) }}
 apiVersion: v1
 kind: Secret
 type: Opaque

k8s/charts/seaweedfs/values.yaml

@@ -897,6 +897,7 @@ filer:
 
   # extraEnvVars is a list of extra environment variables to set with the stateful set.
   extraEnvironmentVars:
+    # the WEED_MYSQL_* keys and the db credential secret only render while this is "true"
     WEED_MYSQL_ENABLED: "false"
     WEED_MYSQL_HOSTNAME: "mysql-db-host"
     WEED_MYSQL_PORT: "3306"