mentat-backup.py

This Mentat module is a script providing PostgreSQL database backup functions and features.

This script is implemented using the pyzenkit.zenscript framework and so it provides all of its core features. See the documentation for more in-depth details.

Usage examples

# Display help message and exit.
mentat-backup.py --help

# Run in debug mode (enable output of debugging information to terminal).
mentat-backup.py --debug

# Run with increased logging level.
mentat-backup.py --log-level debug

Available script commands

backup (default)
Perform backup of data of all configured collections within configured time interval thresholds.
remote-mount
Mount the remote backup storage to local mount point and exit.
remote-unmount
Unmount the remote backup storage from local mount point and exit.
status
Determine the status of backup files on the remote storage.

Custom configuration

Custom command line options

--no-upload

Do not upload the backup file to remote storage (flag).

Type: boolean, default: False

--mount-point dir-name

Name of the mount point directory.

Type: string, default: /media/du-store

--temp-dir dir-name

Name of the log file.

Type: string, default: /var/tmp

--backup-dir dir-name

Name of the log file.

Type: string, default: /var/mentat/backups

--remote-host user@host.domain.org

SSH connection string for the remote host to which to sychronize backups.

Type: string, default: None

--remote-dir dir-name

Directory path on the remote host to which to sychronize backups.

Type: string, default: None

Backup script requirements

To enable backup synchronization to remote machine, SSH access without password must be configured and accessible for the mentat system user. Additionally, the sshfs package must be installed on local machine.

Backup structure

This script produces .tar.gz compressed archives for each run. Each archive contains backups for following databases:

main database

This database us backupped using native pg_dump command and may be restored with its pg_restore counterpart.

Resources: https://www.postgresql.org/docs/current/static/backup-dump.html

event database

This database is backupped only selectively using psql utility. This constraint is due to the possibly huge size of the whole database, to instead the incremental approach is used.

Resources: https://www.postgresql.org/message-id/CAM6mie+8hZPyaXCGgHTwS3=ECzwkLyLn99R4LEtkXgUG7+yNnA@mail.gmail.com

Configuration

The application supports multiple means for adjusting the internal configurations. When appropriate the default values for each configuration is hardcoded in module source code. However there are several options to change the value:

  • Override the internal default value when instantinating the application object by passing different value to object constructor.
  • Pass the different value by configuration file.
  • Pass the different value by command line option.

The configuration values are assigned from the sources mentioned above in that particular order, so the value given by command line option overwrites the value written in configuration file.

Command line options

Configuration can be passed down to application by command line options. These options have the highest priority and will overwrite any other configuration values. Depending on the base object of the application different set of options is available.

Common application options

Following configuration options are available for all applications based on pyzenkit.baseapp:

--help
Display help and usage description and exit (flag)
--name alternative-name

Alternative name for application instead of default $0, using which names for log, runlog, pid, status and other files will be generated.

Type: string, default: $0

--quiet

Run in quiet mode (flag).

Do not write anything to stdout or stderr.

Type: boolean, default: False

--verbose

Increase application output verbosity (flag, repeatable).

Type: boolean, default: False

--log-file file-name

Name of the log file.

Type: string, default: autodetected

--log-level level

Logging level [debug, info, warning, error, critical].

Type: string, default: info

--runlog-dir dir-name

Name of the runlog directory.

Type: string, default: autodetected

--runlog-dump

Dump runlog to stdout when done processing (flag).

Type: boolean, default: False

--runlog_log

Write runlog to logging service when done processing (flag)

Type: boolean, default: False

--pstate_file file-name

Name of the persistent state file.

Type: string, default: autodetected

--pstate_dump

Dump persistent state to stdout when done processing (flag).

Type: boolean, default: False

--pstate_log

Write persistent state to logging service when done processing (flag).

Type: boolean, default: False

--action action

Execute given quick action and exit. List of available actions can be displayed with --help option.

Type: string, default: None

--user name-or-id

Name/gid of the system user for process permissions.

Type: string, default: None

--group name-or-id

Name/gid of the system group for process permissions.

Type: string, default: None

Common script options

Following configuration options are available on top of common applicationsoptions for all applications based on pyzenkit.zenscript:

--regular

Operational mode: regular script execution (flag). Conflicts with --shell option.

Type: boolean, default: False

--shell

Operational mode: manual script execution from shell (flag). Conflicts with --regular option.

Type: boolean, default: False

--command name

Name of the script command to be executed.

Type: string, default: autodetected

--interval interval

Execution interval. This value should correspond with related cron script.

Type: string, default: daily

--adjust_thresholds

Round-up time interval threshols to interval size (flag).

Type: boolean, default: False

--time_high time

Upper time interval threshold.

Type: float, default: time.time

Configuration files and directories

Configuration can be passed down to application using a combination of configuration file or configuration directory. The configuration file

The available configuration keys are very similar to command line options and the names differ only in the use of _ character instead of -. However there is a certain set of configuration keys that is available only through command line options and not through configuration file and vice versa.