azure-cli: developer docs for extensions

Signed-off-by: Paul Meyer <49727155+katexochen@users.noreply.github.com>

pkgs/tools/admin/azure-cli/README.md

@@ -0,0 +1,101 @@
+# Azure CLI
+
+## Extensions
+
+There are two sets of extensions: the one in `extensions-generated.nix` is generated with the script
+`query-extension-index.sh`. These are extensions that don't have external requirements and thus can
+be easily maintained and updated. The set should only be manipulated through an update based on the
+script output.
+
+The other set of extensions is in `extensions-manual.nix`. These are extensions with requirements,
+which need to be packaged and maintained manually.
+
+### Adding an extension to `extensions-manual.nix`
+
+To manually add a missing extension, first query its metadata from the extension index.
+Use the following command, use the current version of azure-cli in nixpkgs as `cli-version`
+and the name of the extension you want to package as `extension`:
+
+```sh
+./query-extension-index.sh --cli-version=2.61.0 --extension=azure-devops --download
+```
+
+The output should look something like this:
+
+```json
+{
+  "pname": "azure-devops",
+  "description": "Tools for managing Azure DevOps.",
+  "version": "1.0.1",
+  "url": "https://github.com/Azure/azure-devops-cli-extension/releases/download/20240514.1/azure_devops-1.0.1-py2.py3-none-any.whl",
+  "sha256": "f300d0288f017148514ebe6f5912aef10c7a6f29bdc0c916b922edf1d75bc7db",
+  "license": "MIT",
+  "requires": [
+    "distro (==1.3.0)",
+    "distro==1.3.0"
+  ]
+}
+```
+
+Based on this, you can add an attribute to `extensions-manual.nix`:
+
+```nix
+  azure-devops = mkAzExtension rec {
+    pname = "azure-devops";
+    version = "1.0.0";
+    url = "https://github.com/Azure/azure-devops-cli-extension/releases/download/20240206.1/azure_devops-${version}-py2.py3-none-any.whl";
+    sha256 = "658a2854d8c80f874f9382d421fa45abf6a38d00334737dda006f8dec64cf70a";
+    description = "Tools for managing Azure DevOps";
+    propagatedBuildInputs = with python3Packages; [
+      distro
+    ];
+    meta.maintainers = with lib.maintainers; [ katexochen ];
+  };
+```
+
+* The attribute name should be the same as `pname`.
+* Replace the version in `url` with `${version}`.
+* The json output `requires` must be transformed into `propagetedBuildInputs`.
+* If `license` is `"MIT"`, it can be left out in the nix expression, as the builder defaults to that license.
+* Add yourself as maintainer in `meta.maintainers`.
+
+### Testing extensions
+
+You can build azure-cli with an extension on the command line by running the following command at the root of this repository:
+
+```sh
+nix build --impure --expr 'with (import ./. {}); azure-cli.withExtensions [ azure-cli.extensions.azure-devops ]'
+```
+
+Check if the desired functionality was added.
+
+You can check if the extensions was recognized by running:
+
+```sh
+./result/bin/az extension list
+```
+
+The output should show the extension like this:
+
+```sh
+[
+  {
+    "experimental": false,
+    "extensionType": "whl",
+    "name": "azure-devops",
+    "path": "/nix/store/azbgnpg5nh5rb8wfvp0r9bmcx83mqrj5-azure-cli-extensions/azure-devops",
+    "preview": false,
+    "version": "1.0.0"
+  }
+]
+```
+
+### Removing an extension
+
+If extensions are removed upstream, an alias is added to the end of `extensions-manual.nix`
+(see `# Removed extensions`). This alias should throw an error and be of similar structure as
+this example:
+
+```nix
+blockchain = throw "The 'blockchain' extension for azure-cli was deprecated upstream"; # Added 2024-04-26
+```

pkgs/tools/admin/azure-cli/extensions-manual.nix

@@ -1,3 +1,7 @@
+# Manually packaged extensions for azure-cli
+#
+# Checkout ./README.md for more information.
+
 { lib
 , mkAzExtension
 , mycli