From 00a0f169f2712a091f47077522b38b152eefcd08 Mon Sep 17 00:00:00 2001
From: Antony Messerli <antony@mes.ser.li>
Date: Mon, 6 Sep 2021 19:22:23 -0500
Subject: [PATCH] Update build.yml

---
 .github/workflows/build.yml | 45 +++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 7beb2c4..5f17c2d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -41,8 +41,49 @@ jobs:
       id: version_check
       continue-on-error: true
       run: |
-        VERSION_TAG=${WEBAPP_RELEASE}-nbxyz1
-        echo "VERSION_TAG=${VERSION_TAG}" >> $GITHUB_ENV
+        tag=latest
+        IMAGE=netbootxyz/netbootxyz
+        TOKEN=$(curl -sX GET \
+            "https://ghcr.io/token?scope=repository%3Anetbootxyz%2Fnetbootxyz%3Apull" \
+            | jq -r '.token')
+          MULTIDIGEST=$(curl -s \
+              --header "Accept: application/vnd.docker.distribution.manifest.v2+json" \
+              --header "Authorization: Bearer ${TOKEN}" \
+              "https://ghcr.io/v2/${IMAGE}/manifests/${tag}" \
+              | jq -r 'first(.manifests[].digest)')
+          DIGEST=$(curl -s \
+              --header "Accept: application/vnd.docker.distribution.manifest.v2+json" \
+              --header "Authorization: Bearer ${TOKEN}" \
+              "https://ghcr.io/v2/${IMAGE}/manifests/${MULTIDIGEST}" \
+              | jq -r '.config.digest')
+          IMAGE_INFO=$(curl -sL \
+            --header "Authorization: Bearer ${TOKEN}" \
+            "https://ghcr.io/v2/${IMAGE}/blobs/${DIGEST}" \
+            | jq -r '.config')
+          IMAGE_RELEASE=$(echo ${IMAGE_INFO} | jq -r '.Labels.build_version' | awk '{print $3}')
+          IMAGE_VERSION=$(echo ${IMAGE_RELEASE} | awk -F'-nbxyz' '{print $1}')
+          NB_RELEASE_NUMBER=$(echo ${IMAGE_RELEASE} | awk -F'-nbxyz' '{print $2}')
+          TAG_SHA=$(git rev-list -n 1 ${IMAGE_RELEASE})
+          if [ -z "${MULTIDIGEST}" ] || [ "${MULTIDIGEST}" == "null" ]; then
+            echo "**** No existing container build found, assuming first build ****"
+            VERSION_TAG=${WEBAPP_RELEASE}-nbxyz1
+            echo "VERSION_TAG=${VERSION_TAG}" >> $GITHUB_ENV
+          elif [ "${WEBAPP_RELEASE}" == "${IMAGE_VERSION}" ]; then
+            echo "**** Version ${WEBAPP_RELEASE} unchanged, checking if there is anything to build..."
+            if [ "${TAG_SHA}" == "${GITHUB_SHA}" ]; then
+              echo "**** Nothing to do, exiting build... **** "
+              exit 1
+            else
+              echo "**** Changes found... incrementing build number version... ****"
+              NB_RELEASE_NUMBER=$((NB_RELEASE_NUMBER + 1))
+              VERSION_TAG=${IMAGE_VERSION}-nbxyz${NB_RELEASE_NUMBER}
+              echo "VERSION_TAG=${VERSION_TAG}" >> $GITHUB_ENV
+            fi
+          else
+            echo "**** New version ${WEBAPP_RELEASE} found; old version was ${IMAGE_VERSION}. Generating new webapp release... ****"
+            VERSION_TAG=${WEBAPP_RELEASE}-nbxyz1
+            echo "VERSION_TAG=${VERSION_TAG}" >> $GITHUB_ENV
+          fi
         
     - name: Docker meta
       if: steps.version_check.outcome == 'success' && steps.version_check.conclusion == 'success'