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

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

@@ -1,6 +1,6 @@
 {
     "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-ubuntu20.04u1", // 2024-02-09 Microsoft's Package Manifest has mismatching filesize and SHA for 0.12.1; default to last known good version
+            "description": "Install a specific version of moby-buildx when using Moby"
+        },
         "dockerDashComposeVersion": {
             "type": "string",
             "enum": [

src/docker-in-docker/install.sh

@@ -10,7 +10,7 @@
 
 DOCKER_VERSION="${VERSION:-"latest"}" # The Docker/Moby Engine + CLI should match in version
 USE_MOBY="${MOBY:-"true"}"
-MOBY_BUILDX_VERSION="${MOBYBUILDXVERSION:-"latest"}"
+MOBY_BUILDX_VERSION="${MOBYBUILDXVERSION}"
 DOCKER_DASH_COMPOSE_VERSION="${DOCKERDASHCOMPOSEVERSION:-"v1"}" # v1 or v2 or none
 AZURE_DNS_AUTO_DETECTION="${AZUREDNSAUTODETECTION:-"true"}"
 DOCKER_DEFAULT_ADDRESS_POOL="${DOCKERDEFAULTADDRESSPOOL}"
@@ -199,20 +199,20 @@ else
     echo "cli_version_suffix ${cli_version_suffix}"
 fi
 
-# Buildx version matching
-if [ "${MOBY_BUILDX_VERSION}" = "latest" ]; then
-    # Empty, meaning grab whatever "latest" is in apt repo
-    buildx_version_suffix=""
-else
-    buildx_version_suffix="=${MOBY_BUILDX_VERSION}"
-    echo "buildx_version_suffix ${buildx_version_suffix}"
-fi
-
 # Install Docker / Moby CLI if not already installed
 if type docker > /dev/null 2>&1 && type dockerd > /dev/null 2>&1; then
     echo "Docker / Moby CLI and Engine already installed."
 else
     if [ "${USE_MOBY}" = "true" ]; then
+        # Buildx version matching
+        if [ "${MOBY_BUILDX_VERSION}" = "latest" ]; then
+            # Empty, meaning grab whatever "latest" is in apt repo
+            buildx_version_suffix=""
+        else
+            buildx_version_suffix="=${MOBY_BUILDX_VERSION}"
+            echo "buildx_version_suffix ${buildx_version_suffix}"
+        fi
+
         # Install engine
         set +e # Handle error gracefully
             apt-get -y install --no-install-recommends moby-cli${cli_version_suffix} moby-buildx${buildx_version_suffix} moby-engine${engine_version_suffix}