Write better readme

Signed-off-by: Nikolai Rodionov <iam@allanger.xyz>

Author: allanger

README.md

@@ -1,11 +1,46 @@
-# pgdump-gcs
+# Postgres backup container for DB Operator
 
-Small docker container for creating a backup of a psql database and upload the dump to an external storage using rclone.
+Small docker container for creating a backup of a psql database and uploading it to an external storage using rclone.
+
+Every backup is uploaded twice, once with a **timestamp** and once as **latest**. So you can always download the latest backup.
+
+There is no clean-up logic, please take care of old backups using external tools, for example bucket retention policies.
+
+## How to restore
+
+This script is simply taking a database backup using `pg_dump`, you can restore it by setting env variables and running the following command:
+
+```shell
+$ export PGHOST=< Database host >
+$ export PGPORT=< Database port >
+$ export PGUSER=< Admin user>
+$ export PGDATABASE=postgres
+$ export PGPASSWORD=< Admin password >
+$ pg_restore --no-owne:wr --no-privileges -d < Target database >  --role < Target username > -Fc < Backup file path> --clean
+```
 
 ## How to use
-TO BE DONE ... 
 
-## monitoring
+This container is supposed to be used by the DB Operator for setting up backup CronJobs. 
+
+To backup a postgres database using this container you need to pass env variables for `pg_dump` and for `rclone`:
+
+**pg_dump** variables:
+
+- **DB_NAME**: A name of a database to back up
+- **DB_HOST**: A database server host
+- **DB_PASSWORD_FILE**: A path to a file with a database password (file must be mounted to the container)
+- **DB_USER**: User that should perform the backup
+
+**rclone** variables:
+
+- **STORAGE_BUCKET**: A name of a bucket/directory that should be used for uploading the backup
+
+For the rest, please check here: <https://rclone.org/docs/#environment-variables>.
+
+The backend name is hardcoded to 'storage', so your env vars should be prefixed by `RCLONE_CONFIG_STORAGE_`
+
+## Monitoring
 
 Simple curl pushing some basic parameter to a prometheus push gateway.
 
@@ -15,6 +50,6 @@ Simple curl pushing some basic parameter to a prometheus push gateway.
 * size
 
 ### labels
-* job = pgdump-gcs
+* job = pgdump-rclone
 * source_type = postgresql
 * source_name = `${DB_NAME}`

entrypoint.sh

@@ -19,13 +19,12 @@ fi
 # create login credential file
 (umask 377 && echo *:5432:*:${DB_USER}:${DB_PASSWORD} >> ~/.pgpass)
 
-echo "Start create backup"
+echo "Backing up"
 pg_dump -F c -Z 9 -h ${DB_HOST} -p 5432 -U ${DB_USER} ${DB_NAME} -f ${BACKUP_FILE}
 BACKUP_SIZE=$(du ${BACKUP_FILE} | awk '{print $1}')
-echo "End backup"
 
 ## copy to destination
-echo "Copy to gcs"
+echo "Uploading to a storage"
 rclone copyto "./${BACKUP_FILE}" "storage://${STORAGE_BUCKET}/${DB_NAME}/${BACKUP_FILE}" 
 rclone copyto "./${BACKUP_FILE}" "storage://${STORAGE_BUCKET}/${DB_NAME}/${BACKUP_FILE_LATEST}"