Add tests to test size of the image to catch regressions (#40)

Add a test to catch a scenario like introduced in
hazelcast/hazelcast-docker#1137, using
https://github.com/wagoodman/dive

Author: JackPGreen

.github/workflows/test-assert-image-size.yml

@@ -0,0 +1,19 @@
+name: Test assert-image-size action
+
+on:
+  workflow_call:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Test scripts
+        run: ./assert-image-size/test_scripts.sh
+
+      - name: Run assert-image-size
+        uses: ./assert-image-size
+        with:
+          image: hazelcast/hazelcast:5.0.1-slim

.github/workflows/test.yml

@@ -10,6 +10,10 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v6
 
+  test-assert-image-size:
+    uses: ./.github/workflows/test-assert-image-size.yml
+    secrets: inherit
+
   test-check-base-images:
     uses: ./.github/workflows/test-check-base-images.yml
 
@@ -44,6 +48,7 @@ jobs:
   assert-all-jobs-succeeded:
     runs-on: ubuntu-latest
     needs:
+      - test-assert-image-size
       - test-check-base-images
       - test-check-if-latest-lts-release
       - test-check-redhat-service-status

assert-image-size/README.md

@@ -0,0 +1,9 @@
+# assert-image-size
+
+A GitHub Action that validates image isn't excessively large / wasting space using [`dive`](https://github.com/wagoodman/dive).
+
+Docker images are built of overlaid [layers](https://docs.docker.com/get-started/docker-concepts/building-images/understanding-image-layers), building on top of one-another. When downloading an image, each layer is downloaded.
+
+If one layer contains a file that is subsequently removed or modified in a subsequent layer, this intermediate state will still be present in the layer to be downloaded, bloating the overall image. An example of this occurred in <https://github.com/hazelcast/hazelcast-docker/pull/1137>.
+
+This action asserts that the amount of wasted space in an image is below a % threshold.

assert-image-size/action.yml

@@ -0,0 +1,23 @@
+name: Test image size
+description: Test image isn't excessively large / wasting space
+
+inputs:
+  image:
+    description: Image name to test
+    required: true
+  minimum_efficiency:
+    description: Minimum efficiency percentage required - 0-1 scale
+    required: false
+    default: 0.95
+
+runs:
+  using: "composite"
+  steps:
+    - shell: bash
+      run: |
+        . ${GITHUB_ACTION_PATH}/assert-image-size.functions.sh
+
+        assert_image_size "${IMAGE}" "${MINIMUM_EFFICIENCY}"
+      env:
+        IMAGE: ${{ inputs.image }}
+        MINIMUM_EFFICIENCY: ${{ inputs.minimum_efficiency }}

assert-image-size/assert-image-size.functions.sh

@@ -0,0 +1,23 @@
+function assert_image_size() {
+  local image=$1
+  local minimum_efficiency=$2
+
+  local config_file
+  config_file=$(mktemp)
+
+  # https://github.com/wagoodman/dive/blob/main/README.md#ci-integration
+  yq eval -n "
+    .rules.lowestEfficiency = ${minimum_efficiency} |
+    .rules.highestWastedBytes = \"disabled\" |
+    .rules.highestUserWastedPercent = \"disabled\"
+  " > "${config_file}"
+
+  docker run --rm \
+    --env CI=true \
+    --volume /var/run/docker.sock:/var/run/docker.sock \
+    --volume "${config_file}:/.dive-ci" \
+    docker.io/wagoodman/dive:latest \
+    "${image}"
+
+  return $?
+}

assert-image-size/assert-image-size.functions_tests.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+
+set -eu ${RUNNER_DEBUG:+-x}
+
+SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
+
+# Source the latest version of assert.sh unit testing library and include in current shell
+source /dev/stdin <<< "$(curl --silent https://raw.githubusercontent.com/hazelcast/assert.sh/main/assert.sh)"
+
+. "$SCRIPT_DIR"/assert-image-size.functions.sh
+
+TESTS_RESULT=0
+
+function assert_assert_image_size {
+  local image=$1
+  local minimum_efficiency=$2
+  local expected_exit_code=$3
+  assert_image_size "${image}" "${minimum_efficiency}" && true
+  local actual_exit_code=$?
+  local msg="Expected exit code for \"${image}\" / \"${minimum_efficiency}\""
+  assert_eq "${expected_exit_code}" "${actual_exit_code}" "${msg}" && log_success "${msg}" || TESTS_RESULT=$?
+}
+
+log_header "Tests for assert_image_size"
+# expected efficiency: 99.8541 %
+assert_assert_image_size hazelcast/hazelcast:5.0.1-slim 0.95 0
+assert_assert_image_size hazelcast/hazelcast:5.0.1-slim 0.99999999999 1
+
+assert_eq 0 "$TESTS_RESULT" "All tests should pass"

assert-image-size/test_scripts.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
+
+find "$SCRIPT_DIR" -name "*_tests.sh" -print0 | xargs -0 -n1 bash