Cron to backup Postgres databases from docker

backup-postgis.sh

#!/bin/bash
BACKUP_FOLDER=/data/sql-backup
BACKUP_FILE_NAME="`date +%Y%m%d`.sql.gz"

EXEC="docker exec -u postgres -i postgis"

databases=$(
    $EXEC psql -l -A -t | awk -F\| '!/^(postgres|template)/{ print $1 }'
)

#
# Dump dos bancos
#
for db in $databases;
do
   folder="${BACKUP_FOLDER%%/}/$db"
   filename="$folder/$BACKUP_FILE_NAME"
   mkdir -p "$folder"
   $EXEC pg_dump -Fp "$db" | gzip > $filename
done

#
# Remove backups mais antigos que 3 meses, menos os que foram criados no domingo
#
find $BACKUP_FOLDER -mtime +90 -name "*.sql.gz" \
| while read backup;
do
    modified_date=`stat -c %Y "$backup"`
    day_of_week=`date --date="@$modified_date" +%u`

    if ! [ "$day_of_week" = "7" ];
    then
        rm "$backup"
    fi
done;

#
# Remove backups mais antigos que 1 ano
#
find $BACKUP_FOLDER -mtime +365 -name "*.sql.gz" -delete