gen_config.sh: add default retenetion of 30 days

Related to this question on our Discourse:
https://discuss.status.im/t/status-node-growing-storage-size/2970

Signed-off-by: Jakub Sokołowski <jakub@status.im>

_assets/scripts/gen_config.sh

@@ -9,6 +9,7 @@ RPC_PORT="${RPC_PORT:-8545}"
 LISTEN_PORT="${LSTEN_PORT:-30303}"
 API_MODULES="${API_MODULES:-eth,web3,admin}"
 MAX_PEERS="${MAX_PEERS:-50}"
+DAYS_KEPT="${DAYS_KEPT-30}"
 FLEET_NAME="${FLEET_NAME:-eth.prod}"
 REGISTER_TOPIC="${REGISTER_TOPIC:-whispermail}"
 MAIL_PASSWORD="${MAIL_PASSWORD:-status-offline-inbox}"
@@ -40,6 +41,7 @@ JQ_FILTER_ARRAY=(
   ".WakuConfig.EnableMailServer = true"
   ".WakuConfig.DataDir = \"${DATA_PATH}/waku\""
   ".WakuConfig.MailServerPassword = \"${MAIL_PASSWORD}\""
+  ".WakuConfig.MailServerDataRetention = ${DAYS_KEPT}"
 )
 
 JQ_FILTER=$(printf " | %s" "${JQ_FILTER_ARRAY[@]}")

config/README.md

@@ -60,11 +60,13 @@ If you want your node to relay Waku(modified Whisper) protocol messages you'll w
         "Enabled": true,
         "EnableMailServer": true,
         "DataDir": "/tmp/status-go-data/waku",
-        "MailServerPassword": "status-offline-inbox"
+        "MailServerPassword": "status-offline-inbox",
+        "MailServerDataRetention": 30
     }
 }
 ```
 The `MailServerPassword` is used for symmetric encryption of history requests.
+The `MailServerDataRetention` defines number of days for which to keep messages.
 
 By default it will use `leveldb` embedded database. To use postgres instead you need to 
 add this to your config: