Allow moby-buildx version to be specified in devcontainer.json (#838)

* Allow moby-buildx version to be specified in devcontainer.json

Fixes #837

* Revert changes to README.md

* Address code review feedback

- Specify mobyBuildxVersion in devcontainer-feature.json with pinned and commented default value
- Bump minor version
- Leverage default value in install.sh
- Only set buildx_version_suffix when installing moby

* Handle varying distributions

* Fix typo / remove extra line

src/docker-in-docker/devcontainer-feature.json

 {
     "id": "docker-in-docker",
-    "version": "2.8.1",
+    "version": "2.9.0",
     "name": "Docker (Docker-in-Docker)",
     "documentationURL": "https://github.com/devcontainers/features/tree/main/src/docker-in-docker",
     "description": "Create child containers *inside* a container, independent from the host's docker instance. Installs Docker extension in the container along with needed CLIs.",
@@ -20,6 +20,11 @@
             "default": true,
             "description": "Install OSS Moby build instead of Docker CE"
         },
+        "mobyBuildxVersion": {
+            "type": "string",
+            "default": "0.12.0",
+            "description": "Install a specific version of moby-buildx when using Moby. (2024-02-09: Microsoft's Package Manifest has mismatching filesize and SHA for 0.12.1; default is last known good version)"
+        },
         "dockerDashComposeVersion": {
             "type": "string",
             "enum": [

src/docker-in-docker/install.sh

@@ -10,6 +10,7 @@
 
 DOCKER_VERSION="${VERSION:-"latest"}" # The Docker/Moby Engine + CLI should match in version
 USE_MOBY="${MOBY:-"true"}"
+MOBY_BUILDX_VERSION="${MOBYBUILDXVERSION}"
 DOCKER_DASH_COMPOSE_VERSION="${DOCKERDASHCOMPOSEVERSION:-"v1"}" # v1 or v2 or none
 AZURE_DNS_AUTO_DETECTION="${AZUREDNSAUTODETECTION:-"true"}"
 DOCKER_DEFAULT_ADDRESS_POOL="${DOCKERDEFAULTADDRESSPOOL}"
@@ -198,6 +199,27 @@ else
     echo "cli_version_suffix ${cli_version_suffix}"
 fi
 
+# Version matching for moby-buildx
+if [ "${USE_MOBY}" = "true" ]; then
+    if [ "${MOBY_BUILDX_VERSION}" = "latest" ]; then
+        # Empty, meaning grab whatever "latest" is in apt repo
+        buildx_version_suffix=""
+    else
+        buildx_version_dot_escaped="${MOBY_BUILDX_VERSION//./\\.}"
+        buildx_version_dot_plus_escaped="${buildx_version_dot_escaped//+/\\+}"
+        buildx_version_regex="^(.+:)?${buildx_version_dot_plus_escaped}([\\.\\+ ~:-]|$)"
+        set +e
+            buildx_version_suffix="=$(apt-cache madison moby-buildx | awk -F"|" '{print $2}' | sed -e 's/^[ \t]*//' | grep -E -m 1 "${buildx_version_regex}")"
+        set -e
+        if [ -z "${buildx_version_suffix}" ] || [ "${buildx_version_suffix}" = "=" ]; then
+            err "No full or partial moby-buildx version match found for \"${MOBY_BUILDX_VERSION}\" on OS ${ID} ${VERSION_CODENAME} (${architecture}). Available versions:"
+            apt-cache madison moby-buildx | awk -F"|" '{print $2}' | grep -oP '^(.+:)?\K.+'
+            exit 1
+        fi
+        echo "buildx_version_suffix ${buildx_version_suffix}"
+    fi
+fi
+
 # Install Docker / Moby CLI if not already installed
 if type docker > /dev/null 2>&1 && type dockerd > /dev/null 2>&1; then
     echo "Docker / Moby CLI and Engine already installed."
@@ -205,7 +227,7 @@ else
     if [ "${USE_MOBY}" = "true" ]; then
         # Install engine
         set +e # Handle error gracefully
-            apt-get -y install --no-install-recommends moby-cli${cli_version_suffix} moby-buildx moby-engine${engine_version_suffix}
+            apt-get -y install --no-install-recommends moby-cli${cli_version_suffix} moby-buildx${buildx_version_suffix} moby-engine${engine_version_suffix}
             if [ $? -ne 0 ]; then
                 err "Packages for moby not available in OS ${ID} ${VERSION_CODENAME} (${architecture}). To resolve, either: (1) set feature option '\"moby\": false' , or (2) choose a compatible OS version (eg: 'ubuntu-20.04')."
                 exit 1