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Converting Lua Upgrade Scripts to Python Data Migrations

To convert migrations (a.k.a. "upgrade scripts") that were originally written in Lua, we need to get the version that the migration upgrades from, the object type the migration is written for, and lastly convert the code into Python code using the decorators described previously.


Assume there are two versions of a lua toolkit, 1.0.0 and 1.1.0 where the 1.1.0 version is following the basic toolkit directory structure (actually containing all operations):

├── main.json
├── discovery 
│   ├── repositoryDiscovery.lua
│   └── sourceConfigDiscovery.lua
├── staged 
│   ├── mountSpec.lua
│   ├── ...
│   └── worker.lua
├── virtual 
│   ├── configure.lua
│   ├── ...
│   └── unconfigure.lua
├── upgrade 
│   └── 1.0
│       ├── upgradeLinkedSource.lua
│       ├── ...
│       └── upgradeVirtualSource.lua
├── resources 
└── ├──
    ├── ...

upgradeLinkedSource.lua contains:

parameters.dsOldValue = "remove"
parameters.dsUpdateValue = 1
parameters.dsLanguage = "LUA"
return parameters

This can be equalivalently converted into the python code:

from dlpx.virtualization.platform import Plugin

plugin = Plugin()

@plugin.upgrade.linked_source("1.0", MigrationType.LUA)
def upgrade_linked_source(old_linked_source):
  new_linked_source = dict(old_linked_source)
  new_linked_source["dsOldValue"] = "remove"
  new_linked_source["dsUpdateValue"] = 1
  new_linked_source["dsLanguage"] = "LUA"
  return new_linked_source

You will need to determine how far back in the Lua upgrade chain you want to support multi-step upgrade from, and convert all of those upgrade scripts accordingly. Remember that the execution of these scripts relies on there not being any missing migrations from the minimumLuaVersion defined in the plugin config to the last toolkit version written. Lua migrations will be executed from the lowest to highest version that exists. When executing, these migrations are run to the highest Lua toolkit version only. Any migrations needed to get from that toolkit to the Python plugin would need to be written as a regular Python migration.