[ docker-in-docker ] - buildx can fallback to previous version if latest artifact not found (#869)

* [ docker-in-docker ] - buildx fallback to prev. version

* corrected the command inside get_previous_version fn to get the second to latest version instead

* changes in response to comments by @samruddhikhandale

* minor change

* changes as requested in comments by @samruddhikhandale

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

 {
     "id": "docker-in-docker",
-    "version": "2.9.0",
+    "version": "2.9.1",
     "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.",

src/docker-in-docker/install.sh

@@ -139,7 +139,7 @@ else
 fi
 
 # Install dependencies
-check_packages apt-transport-https curl ca-certificates pigz iptables gnupg2 dirmngr wget
+check_packages apt-transport-https curl ca-certificates pigz iptables gnupg2 dirmngr wget jq
 if ! type git > /dev/null 2>&1; then
     check_packages git
 fi
@@ -332,14 +332,36 @@ fi
 
 usermod -aG docker ${USERNAME}
 
+# Function to fetch the version released prior to the latest version
+get_previous_version() {
+    repo_url=$1
+    curl -s "$repo_url" | jq -r 'del(.[].assets) | .[1].tag_name' # this would del the assets key and then get the second encountered tag_name's value from the filtered array of objects
+}
+
+install_previous_version_artifacts() {
+    wget_exit_code=$?
+    if [ $wget_exit_code -eq 8 ]; then  # failure due to 404: Not Found.
+        echo -e "\n(!) Failed to fetch the latest artifacts for docker buildx v${buildx_version}..."
+        repo_url="https://api.github.com/repos/docker/buildx/releases" # GitHub repository URL
+        previous_version=$(get_previous_version "${repo_url}")
+        buildx_file_name="buildx-${previous_version}.linux-${architecture}"
+        echo -e "\nAttempting to install ${previous_version}"
+        wget https://github.com/docker/buildx/releases/download/${previous_version}/${buildx_file_name}
+    else
+        echo "(!) Failed to download docker buildx with exit code: $wget_exit_code"
+        exit 1
+    fi
+}
+ 
 if [ "${INSTALL_DOCKER_BUILDX}" = "true" ]; then
     buildx_version="latest"
     find_version_from_git_tags buildx_version "https://github.com/docker/buildx" "refs/tags/v"
-
     echo "(*) Installing buildx ${buildx_version}..."
     buildx_file_name="buildx-v${buildx_version}.linux-${architecture}"
-    cd /tmp && wget "https://github.com/docker/buildx/releases/download/v${buildx_version}/${buildx_file_name}"
-
+    
+    cd /tmp
+    wget https://github.com/docker/buildx/releases/download/v${buildx_version}/${buildx_file_name} || install_previous_version_artifacts
+    
     docker_home="/usr/libexec/docker"
     cli_plugins_dir="${docker_home}/cli-plugins"
 

test/docker-in-docker/docker_build_fallback_buildx.sh

+#!/bin/bash
+
+set -e
+
+# Optional: Import test library
+source dev-container-features-test-lib
+
+# Definition specific tests before test for fallback
+HL="\033[1;33m"
+N="\033[0;37m"
+echo -e "\n👉${HL} docker/buildx version as installed by docker-in-docker feature${N}"
+check "docker-buildx" docker buildx version
+check "docker-build" docker build ./
+check "docker-buildx" bash -c "docker buildx version"
+check "docker-buildx-path" bash -c "ls -la /usr/libexec/docker/cli-plugins/docker-buildx"
+
+echo -e "\n👉${HL} Creating a scenario for fallback${N}\n"
+# Code to test the made up scenario when latest version of docker/buildx fails on wget command for fetching the artifacts
+repo_url="https://api.github.com/repos/docker/buildx/releases" # GitHub repository URL
+architecture="$(dpkg --print-architecture)"
+
+# Function to fetch the latest version of the plugin
+get_latest_version() {
+    curl -s "$repo_url/latest" | jq -r '.tag_name'
+}
+
+# Function to fetch the previous version of the plugin
+get_previous_version() {
+    curl -s "$repo_url" | jq -r 'del(.[].assets) | .[1].tag_name' # this would del the assets key and then get the second encountered tag_name's value from the filtered array of objects
+}
+
+# Function to change the patch number in a semver version
+change_patch_number() {
+    local version="$1"  # Input version
+    local new_patch="$2"  # New patch number
+    # Extract major, minor, and current patch numbers
+    local major=$(echo "$version" | cut -d. -f1)
+    local minor=$(echo "$version" | cut -d. -f2)
+    local current_patch=$(echo "$version" | cut -d. -f3)
+    # Construct the new version with the updated patch number
+    local new_version="$major.$minor.$new_patch"
+    echo "$new_version"
+}
+
+change_version_to_fail() {
+    latest_version=$1
+    new_patch_number="xyz" # for testing a tag not found scenario for docker/buildx plugin
+    latest_version=$(get_latest_version)  # can take latest_version from fn get_latest_version
+    buildx_version_fallback_test=$(change_patch_number "$latest_version" "$new_patch_number") # for testing a tag not found scenario for docker/buildx plugin
+    echo "${buildx_version_fallback_test}"
+}
+
+install_previous_version_artifacts() {
+    wget_exit_code=$?
+    if [ $wget_exit_code -ne 0 ]; then # means wget command to fetch latest version failed
+        if [ $wget_exit_code -eq 8 ]; then  # failure due to 404: Not Found.
+            echo -e "\n(!) Failed to fetch the latest artifacts for docker buildx ${buildx_version}..."
+            previous_version=$(get_previous_version)
+            echo -e "\nAttempting to install ${previous_version}"
+            buildx_file_name="buildx-${previous_version}.linux-${architecture}"
+            wget https://github.com/docker/buildx/releases/download/${previous_version}/${buildx_file_name}
+        else
+            echo "(!) Failed to download docker buildx with exit code: $wget_exit_code"
+            exit 1
+        fi
+    fi
+}
+    
+test_version=$(change_version_to_fail "$(get_latest_version)")
+buildx_file_name="buildx-${test_version}.linux-${architecture}"
+buildx_version=$test_version
+
+# This wget command will fail as the wrong version won't fetch artifact
+wget https://github.com/docker/buildx/releases/download/${buildx_version}/${buildx_file_name} || install_previous_version_artifacts
+
+docker_home="/usr/libexec/docker"
+cli_plugins_dir="${docker_home}/cli-plugins"
+
+mkdir -p ${cli_plugins_dir}
+mv ${buildx_file_name} ${cli_plugins_dir}/docker-buildx
+chmod +x ${cli_plugins_dir}/docker-buildx
+
+chown -R "${USERNAME}:docker" "${docker_home}"
+chmod -R g+r+w "${docker_home}"
+find "${docker_home}" -type d -print0 | xargs -n 1 -0 chmod g+s
+
+# Definition specific tests after test for fallback
+echo -e "\n👉${HL} docker/buildx version as installed by test for fallback${N}"
+check "docker-buildx" docker buildx version
+check "docker-build" docker build ./
+check "docker-buildx" bash -c "docker buildx version"
+check "docker-buildx-path" bash -c "ls -la /usr/libexec/docker/cli-plugins/docker-buildx"
+
+# Report result
+reportResults

test/docker-in-docker/scenarios.json

@@ -87,6 +87,17 @@
             }
         }
     },
+    "docker_build_fallback_buildx": {
+        "image": "ubuntu:focal",
+        "features": {
+            "docker-in-docker": {
+                "version": "latest",
+                "installDockerBuildx": true,
+                "moby": "false",
+                "dockerDashComposeVersion": "v2"
+            }
+        }
+    },
     // DO NOT REMOVE: This scenario is used by the docker-in-docker-stress-test workflow
     "docker_with_on_create_command": {
         "image": "mcr.microsoft.com/devcontainers/base:debian",