• 1. Azure Cache for NHK World TV Kodi Plugin
  • 1.1. Disclaimer
  • 1.2. Overview
  • 1.3. Design & Implementation on Azure
  • 1.4. Azure Functions
  • 1.5. CosmosDB Set-up
  • 1.6. Development Environment
  • 1.7. Deployment on Azure

This Azure Function is a fan project and not related in any way to NHK! I built this solution because NHK does not support Android TV (yet).

NHK World TV is a Kodi plug-in that displays most of the content from NHK World Japan in Kodi.

This repo provides a persistent backend-cache hosted on Microsoft Azure Storage to speed up episode video Url lookup operations where the NHK API is very slow.

The cache is implemented as a set of Azure Functions backed by a CosmosDB (free tier) in "SQL-Mode". It's 100% serverless/PaaS.

That was the easiest, most cost effective (because of CosmosDB free tier and serverless), lowest operations and most importantly, most fun way of doing things for me.

Azure Functions are implemented in sbroennelab.nhkworldtv .Net 6 project using Azure Functions v4 in C#. The Unit Tests can be found in sbroennelab.nhkworldtv.Tests project (I am using xUnit).

The function app has been deployed to Azure in West Europe (I live in Germany)

There are two Timer-Trigger functions:

• UpdateBlob - creates a JSON file with the paths (1080P and 720P) for the episodes of the video-on-demand programs on Azure Storage. The Kodi addon loads this file on start-up.
• PopulateCache - updates the the episode information in CosmosDB

If you need to access the file outside the add-on, here is the link.

The Azure function use its system-managed identity to access Cosmos DB and the storage account.

There is a an ARM template you can deploy in sbroennelab.nhkworldtv/arm/cosmosdb-nhkdb. It will create the CosmosDB nhkdb in the resource group nhkworldtv in West Europe ny default. It will create a container VodProgram.

I develop with Visual Studio Code on a Windows 11 box using WSL2 running Ubuntu (remote/WLS2 based development).

I use the Azurite extension instead of the Azure Storage Emulator.

Important hint while unit testing: You need to set the application setting as Environment variables in Windows 11/WSLv2 if you want to run the unit tests from the test runner (in my case .NET Test Explorer). Otherwise the functions will not find them - even though they are defined and used in local.settings.json.

It is a pure .Net 8 solution so you should be able to use any DEV environment you prefer. I also tested it on Visual Studio 2022.

You will need to add the following Application Settings in your function app:

  {
    "name": "BLOB_NAME",
    "value": nhkworldtv",
    "slotSetting": false
  },

  {
    "name": "DATABASE_ID",
    "value": "<your CosmosDB database value>",
    "slotSetting": false
  },
  {
    "name": "DATABASE_CONTAINER_VOD_PROGRAM",
    "value": "VodProgram",
    "slotSetting": false
  },
  {
    "name": "ENDPOINT_URL",
    "value": "<your Cosmos DB endpoint value>",
    "slotSetting": false
  }