feat: Add manifest installation script

This script downloads the latest manifest from GitHub Releases.
With this manifest installed, the .NET SDK can locate and install
other workload packages.

README.md

@@ -2,6 +2,33 @@
 
 An attempt to create a .NET SDK workload that provides the `net8.0-haiku` TFM.
 
+## Installation
+
+To install, run the `install-manifest.sh` script:
+
+```sh
+bash -c "$(curl -fsSL https://raw.githubusercontent.com/trungnt2910/dotnet-haiku/HEAD/install-manifest.sh)"
+```
+
+The script requires `dotnet`, `curl`, `jq`, and `unzip` to be installed and be available in `$PATH`.
+It installs the latest version of the [advertising manifests](https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-workload-install#advertising-manifests) for the Haiku workload.
+
+After that, the `haiku` workload will be available for install like any other workload:
+
+```sh
+dotnet workload install haiku
+```
+
+Note that you have to subscribe to **[@trungnt2910](https://github.com/trungnt2910)**'s GitHub Packages feed.
+If .NET for Haiku from the [dotnet-builds](https://github.com/trungnt2910/dotnet-builds/tree/master#installation) repository has already been installed, you have already subscribed to this feed.
+Otherwise, run:
+
+```sh
+dotnet nuget add source --username your_github_username --password your_github_token --store-password-in-clear-text --name dotnet_haiku_nuget "https://nuget.pkg.github.com/trungnt2910/index.json"
+```
+
+`your_github_token` should be a [personal access token](https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-nuget-registry#authenticating-to-github-packages) with at least the `read:packages` permission.
+
 ## Building instructions
 
 ### Clone this repository

install-manifest.sh

@@ -0,0 +1,89 @@
+#!/bin/bash -e
+
+DOTNET_PATH="dotnet"
+
+if [ -z "$DOTNET_ROOT" ]; then
+    DOTNET_PATH=$(command -v dotnet)
+else
+    DOTNET_PATH="$DOTNET_ROOT/dotnet"
+fi
+
+if [ -z "$DOTNET_PATH" ]; then
+    echo "Could not find dotnet. Install dotnet and try again."
+    exit 1
+fi
+
+echo "Using dotnet from $DOTNET_PATH"
+
+DOTNET_VERSION=$(eval "$DOTNET_PATH --version")
+
+echo "Detected .NET SDK version $DOTNET_VERSION"
+
+set +e
+
+prereleaseStart=$(($(expr index "$DOTNET_VERSION" "-") - 1))
+
+if [ "$prereleaseStart" -gt 0 ]; then
+    firstDot=$(expr index "${DOTNET_VERSION:$(($prereleaseStart + 1)):${#DOTNET_VERSION}}" ".")
+    firstDot=$(($firstDot + $prereleaseStart))
+    secondDot=$(expr index "${DOTNET_VERSION:$((firstDot + 1)):${#DOTNET_VERSION}}" ".")
+
+    if [ "$secondDot" -eq 0 ]; then
+        secondDot="${#DOTNET_VERSION}"
+    else
+        secondDot=$(($secondDot + $firstDot))
+    fi
+
+    DOTNET_FEATURE_BAND="${DOTNET_VERSION:0:$secondDot}"
+else
+    DOTNET_FEATURE_BAND="${DOTNET_VERSION:0:$((${#DOTNET_VERSION} - 2))}00"
+fi
+
+set -e
+
+echo "Detected .NET SDK feature band $DOTNET_FEATURE_BAND"
+
+GITHUB_SERVER_URL=${GITHUB_SERVER_URL:-"https://github.com"}
+GITHUB_API_URL=${GITHUB_API_URL:-"https://api.github.com"}
+GITHUB_REPOSITORY=${GITHUB_REPOSITORY:-"trungnt2910/dotnet-haiku"}
+
+manifestName="trungnt2910.net.sdk.haiku"
+manifestPackageName="$manifestName.manifest-$DOTNET_FEATURE_BAND"
+
+manifestPackageVersion=""
+releaseUrl="$GITHUB_SERVER_URL/$GITHUB_REPOSITORY/releases/tag/"
+pageNum=1
+while [ -z "$manifestPackageVersion" ];
+do
+    json=$(curl -s $GITHUB_API_URL/repos/$GITHUB_REPOSITORY/releases?page=$pageNum)
+    pageNum=$((pageNum + 1))
+    if [ $(echo $json | jq length) -eq 0 ]; then
+        # This means that we've passed the end and reached an empty array
+        break
+    fi
+    if [ $(echo $json | jq 'objects // {} | has("message")') == "true" ]; then
+        # API has return an error object
+        echo "Unable to fetch releases from GitHub API"
+        exit 2
+    fi
+    # Store array of revisions
+    revisions=($(echo $json | jq -e -r ".[] | .html_url | select(true)[${#releaseUrl}:]")) \
+        || continue
+    manifestPackageVersion=${revisions[0]}
+done
+
+echo "Latest manifest package version is $manifestPackageVersion"
+
+manifestPackageUrl="$GITHUB_SERVER_URL/$GITHUB_REPOSITORY/releases/download/$manifestPackageVersion/$manifestPackageName.$manifestPackageVersion.nupkg"
+
+echo "Downloading manifest package from $manifestPackageUrl"
+
+manifestInstallDir="$(dirname "$DOTNET_PATH")/sdk-manifests/$DOTNET_FEATURE_BAND/$manifestName"
+
+tmpFilePath="$(mktemp)"
+curl -sL $manifestPackageUrl -u $GITHUB_USERNAME:$GITHUB_TOKEN -o $tmpFilePath
+unzip -j $tmpFilePath 'data/*.*' -d $manifestInstallDir
+rm $tmpFilePath
+
+echo "Installed manifest package to $manifestInstallDir"
+echo "Run '$DOTNET_PATH workload install haiku' to install the Haiku workload."