upgrade-oc 1.1.0

Generic functions for handling upgrading services

Upgrade by Ouroboros Coding Inc.

Methods to easily update data associated with services and projects created by Ouroboros Coding Inc. to their latest version.

Installing

pip install upgrade_oc

Using

Upgrade comes with a class, 3 methods, and a compiled regular expression.

UpgradeMessages

In order to support additional languages, or simply different ways to put things, you can overwrite any of the message strings used by upgrade via your own UpgradeMessages instance.

The current default messages can be found in the types.py file. Since each variable in the class has a default, you can pick and choose which messages you want to replace.

from upgrade_oc import UpgradeMessages

# Override just no_file and no_path
my_messages = UpgradeMessages(
	no_file = ('#' * 40) + '\nThe file at %s could not be found.\n' + ('#' * 40)
	no_path = ('#' * 40) + '\nNo path %s exists.\n' + ('#' * 40)
)

set_latest

Sets the current version to the last upgradable version. This is useful if the system is being installed from scratch and will already be up to date. If no upgrade scripts are found, uses the initial value which has a default of "1.0.0"

install.py

from upgrades_oc import set_latest
from pathlib import Path

set_latest(
  '../data',
  Path(__file__).parent.resolve()
)

Assuming a module structure of

├── my_module/
│   ├── install.py
│   ├── uninstall.py
│   ├── upgrade.py
│   └── upgrades/
│       ├── __init__.py
│       ├── v1_0_1_v1_1_0.py
│       ├── v1_1_0_v1_1_1.py
│       ├── v1_1_1_v2_2_0.py
│       └── v2_2_0_v2_3_0.py
└── data/

This would create a new file data/my_module.ver which contained the value

2.3.0

If we wanted to substitute the messages for our own

set_latest(
  '../data',
  Path(__file__).parent.resolve(),
  messages = my_messages
)

uninstall

Removes the version file. In the previous example, calling uninstall would remove the data/my_module.ver file from the system

uninstall.py

from upgrades_oc import set_latest
from pathlib import Path

uninstall(
  '../data',
  Path(__file__).parent.resolve(),
  messages = my_messages
)

upgrade

Runs the upgrade scripts found in the upgrades directory one at a time from the current version until we achieve the latest. Keep this in mind if you plan on supporting upgrading multiple versions at once, as any imports in the upgrade scripts will need to still be available and run as expected at the time of the upgrade scripts writing. This is not an issue if you choose to change version, upgrade, change version again, and upgrade again.

upgrade.py

from upgrade_oc import upgrade
from pathlib import Path

upgrade(
	'../data',
	Path(__file__).parent.resolve(),
	messages = my_messages
)

upgrade on projects

If you are running upgrade on a project, something that can not reference itself, be sure to set the mode flag to 'project' so that upgrade knows to look for the upgrades folder in the current working directory.

├── my_project
│   ├── .data/
│   ├── upgrade.py
│   └── upgrades/
│       ├── __init__.py
│       ├── v1_0_0_v1_1_0.py
│       ├── v1_1_0_v1_1_1.py

upgrade.py

from upgrade_oc import upgrade
from pathlib import Path

upgrade(
	'./.data',
	Path(__file__).parent.resolve(),
	mode = 'project'
	messages = my_messages
)

Which would result in the file my_project/.data/my_project.ver containing

1.1.1

UpgradeScriptRegex

This compiled regular expression is represents the file name structure for upgrade scripts. Described below

Upgrade Script format

A version file is in the format, version to convert from underscore version to convert to, python extension. Where the periods in the version are also underscores.

So if we were at version 1.0.0, and wanted to go to version 1.1.0:

v1_0_0_v1_1_0.py

or from 1.1.0 to 1.1.1

v1_1_0_v1_1_1.py

Versions have to be sequencial, and one must tie into the previous, but you are not required to enter every version of your software, just the ones that require something to be run in order to upgrade. The following list

│   └── upgrades/
│       ├── __init__.py
│       ├── v1_0_0_v1_0_1.py
│       ├── v1_0_1_v1_0_2.py
│       ├── v1_0_2_v1_0_3.py
│       ├── v1_0_3_v1_0_4.py

Is as valid as

│   └── upgrades/
│       ├── __init__.py
│       ├── v1_0_0_v2_34_1.py
│       ├── v2_34_1_v2_48_6.py
│       ├── v2_48_6_v10_0_0.py
│       ├── v10_0_0_v10_0_1.py

Upgrade Script internals

The only thing required in an upgrade script is a run() method that returns True on success or False on failure.

v2_48_6_v10_0_0.py

"""2.48.6 to 10.0.0
This upgrade script will convert to 10.0.0 from 2.48.6
"""
def run():
	try:
		""" do stuff to upgrade """
		return True
	except Exception:
		return False