From 2dff0c273532ea9b5407714363335b481ab457af Mon Sep 17 00:00:00 2001
From: Carolyn Maynard <carolyn.maynard@rtx.com>
Date: Tue, 12 May 2026 15:30:12 -0700
Subject: [PATCH] Update ngwpc-cicd.yml to bust EWTS Docker cache when remote
 ref changes

Resolve EWTS_REF to commit SHA in workflow and pass as EWTS_CACHE_BUST build arg. Ensures Docker rebuilds EWTS layer when branch/tag HEAD changes while keeping cache stable for fixed commit hashes.
---
 .github/workflows/ngwpc-cicd.yml | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/.github/workflows/ngwpc-cicd.yml b/.github/workflows/ngwpc-cicd.yml
index 07f7f8c80f..f6c7127140 100644
--- a/.github/workflows/ngwpc-cicd.yml
+++ b/.github/workflows/ngwpc-cicd.yml
@@ -83,6 +83,7 @@ jobs:
       ngen_forcing_digest: ${{ steps.vars.outputs.ngen_forcing_digest }}
       ngen_forcing_revision: ${{ steps.vars.outputs.ngen_forcing_revision }}
       ewts_revision: ${{ steps.vars.outputs.ewts_revision }}
+      ewts_cache_bust: ${{ steps.vars.outputs.ewts_cache_bust }}
     steps:
       - name: Compute image vars
         id: vars
@@ -171,6 +172,21 @@ jobs:
 
           EWTS_REVISION=$(resolve_sha "https://github.com/${{ inputs.EWTS_ORG || github.repository_owner }}/nwm-ewts.git" "$(ref_or_default "${{ inputs.EWTS_REF }}")")
 
+          # Resolve EWTS ref for Docker cache busting
+          EWTS_ORG="${{ inputs.EWTS_ORG || github.repository_owner }}"
+          EWTS_REF="${{ inputs.EWTS_REF || 'development' }}"
+
+          if [[ "${EWTS_REF}" =~ ^[0-9a-f]{7,40}$ ]]; then
+            EWTS_CACHE_BUST="${EWTS_REF}"
+          else
+            EWTS_CACHE_BUST="$(git ls-remote "https://github.com/${EWTS_ORG}/nwm-ewts.git" "${EWTS_REF}" | awk '{print $1}')"
+          fi
+
+          if [ -z "${EWTS_CACHE_BUST}" ]; then
+            echo "ERROR: Could not resolve EWTS_REF=${EWTS_REF}"
+            exit 1
+          fi
+
           # save outputs
           cat >> "$GITHUB_OUTPUT" <<EOF
           org=${ORG}
@@ -184,6 +200,7 @@ jobs:
           ngen_forcing_digest=${NGEN_FORCING_DIGEST}
           ngen_forcing_revision=${NGEN_FORCING_REVISION}
           ewts_revision=${EWTS_REVISION}
+          ewts_cache_bust=${EWTS_CACHE_BUST}
           EOF
 
   # CodeQL scan
@@ -343,6 +360,7 @@ jobs:
             EWTS_ORG=${{ inputs.EWTS_ORG || github.repository_owner }}
             EWTS_REF=${{ inputs.EWTS_REF || needs.setup.outputs.default_ref }}
             EWTS_REVISION=${{ needs.setup.outputs.ewts_revision }}
+            EWTS_CACHE_BUST=${{ needs.setup.outputs.ewts_cache_bust }}
             IMAGE_SOURCE=https://github.com/${{ github.repository }}
             IMAGE_VENDOR=${{ github.repository_owner }}
             IMAGE_VERSION=${{ needs.setup.outputs.clean_ref }}