Enable optional DB URL auto-assembly for MySQL

Signed-off-by: kahirokunn <okinakahiro@gmail.com>

Author: kahirokunn

charts/devlake/templates/deployments.yaml

@@ -197,7 +197,7 @@ spec:
           env:
             - name: PORT
               value: "{{ .Values.lake.port }}"
-            {{- if (eq .Values.option.database "mysql") }}
+            {{- if and (eq .Values.option.database "mysql") (.Values.option.assembleDbUrl) }}
             - name: DB_URL
               value: "mysql://$(MYSQL_USER):$(MYSQL_PASSWORD)@$(MYSQL_SERVER):$(MYSQL_PORT)/$(MYSQL_DATABASE)?charset=$(DB_CHARSET)&parseTime=$(DB_PARSE_TIME)&loc=$(DB_LOCATION){{ .Values.mysql.extraParams }}"
             {{- end }}

charts/devlake/values.yaml

@@ -437,6 +437,10 @@ option:
   # the existing k8s secret name of db connection auth. The secret name should be as same as .Values.grafana.envFromSecret
   connectionSecretName: "devlake-mysql-auth"
   autoCreateSecret: true
+  # If true, the chart assembles DB_URL automatically for MySQL. Set to false
+  # to disable auto-assembly and provide DB_URL yourself via `lake.envs` or
+  # an external secret referenced by `lake.extraEnvsFromSecret`.
+  assembleDbUrl: true
 
 # Define some extra resources to be created
 # This section is useful when you need ExternalResource or Secrets, etc.