2.9 KiB
Database Backup Contract
This NixOS contract represents a backup job that will backup everything in one database on a regular schedule.
It is a contract between a service that has database dumps to be backed up and a service that backs up databases dumps.
Contract Reference
These are all the options that are expected to exist for this contract to be respected.
id-prefix: contracts-databasebackup-options-
list-id: selfhostblocks-options
source: @OPTIONS_JSON@
Usage
A database that can be backed up will provide a databasebackup option.
What this option defines is, from the user perspective - that is you - an implementation detail but it will at least define how to create a database dump, the user to backup with and how to restore from a database dump.
Here is an example module defining such a databasebackup option,
which defines the user to backup with (user)
and how to backup (backupCmd) and restore (restoreCmd) the database:
{
options = {
myservice.databasebackup = mkOption {
type = shb.contracts.databasebackup.mkRequester = {
user = "myservice";
backupCmd = ''
${pkgs.postgresql}/bin/pg_dumpall | ${pkgs.gzip}/bin/gzip --rsyncable
'';
restoreCmd = ''
${pkgs.gzip}/bin/gunzip | ${pkgs.postgresql}/bin/psql postgres
'';
};
};
};
};
Now, on the other side we have a service that uses this databasebackup option and actually backs up files.
This service is a provider of this contract and will provide a result option.
Let's assume such a module is available under the databaseBackupService option
and that one can create multiple backup instances under databaseBackupService.instances.
Then, to actually backup the myservice service, one would write:
databaseBackupService.instances.myservice = {
request = myservice.databasebackup.request;
settings = {
enable = true;
repository = {
path = "/srv/backup/myservice";
};
# ... Other options specific to backupservice like scheduling.
};
};
It is advised to backup files to different location, to improve redundancy.
Thanks to using contracts, this can be made easily either with the same databaseBackupService:
databaseBackupService.instances.myservice_2 = {
request = myservice.databasebackup.request;
settings = {
enable = true;
repository = {
path = "<remote path>";
};
};
};
Or with another module databaseBackupService_2!