matrix_synapse_purge_history_multi_room.sh

#!/bin/bash
# This script purges the local history older than 90 days in some rooms, that you can define in an array
# 
# crontab -e
# 23 4  *   *   *     bash /home/irc-bridge/.synapse/EIGENE_purge_history_daily > /dev/null 2>&1

cd /home/irc-bridge/.synapse/

DOMAIN="matrix.yourserver.org"
ADMIN="@some_adminuser:matrix.yourserver.org"
TOKEN=$(psql -t -A --dbname="synapse" --command="select token from access_tokens where user_id='$ADMIN' order by id desc limit 1;" |grep -v "Pager")
#------------------

TIME='90 days ago'
UNIX_TIMESTAMP=$(date +%s%3N --date='TZ="UTC+2" '"$TIME")

#rooms
ROOMS_ARRAY=(
'!kctHiBoIzDvfWZiGxI:matrix.yourserver.org'
'!gNfrEAqZhLtlSwOAYS:matrix.yourserver.org'
'!WgdJDQCGXmzzsYfGuo:matrix.yourserver.org'
'!iKYnoXwCXUpxsRFQrI:matrix.yourserver.org' 
'!MBBFSjjzZSUazforjQ:matrix.yourserver.org'
)

for ROOM_NAME in "${ROOMS_ARRAY[@]}"
do
   :
        EVENT_ID=$(psql -A -t --dbname="synapse" --command="select event_id from events where type='m.room.message' and received_ts<'$UNIX_TIMESTAMP' and room_id='$ROOM_NAME' order by received_ts desc limit 1;"|grep -v 'Pager')
        sleep 1
        curl -X POST $DOMAIN':8008/_matrix/client/r0/admin/purge_history/'$ROOM_NAME'/'$EVENT_ID'?access_token='$TOKEN
        sleep 1 
done

This script purges the local history in some rooms, that you can define in an array

A nice script. Another idea for cleaning all rooms without a defined array:

ROOMS=$(sudo -u postgres psql -t -A --dbname="synapse" --command="SELECT room_id FROM rooms;")

and

for ROOM_NAME in $ROOMS
...