From c53c8d533e6f617368858278e7ea6bf33b71517d Mon Sep 17 00:00:00 2001
From: Sam Mesterton-Gibbons <sam.mesterton-gibbons@bbc.co.uk>
Date: Thu, 14 Sep 2023 10:31:49 +0100
Subject: [PATCH 1/3] Only run docs upload on changes

Updates CI pipeline to only upload documentation if there's been a
change since the last successful build.
---
 .github/workflows/ci-workflow.yml | 32 ++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/ci-workflow.yml b/.github/workflows/ci-workflow.yml
index 683b2c5..f5b7185 100644
--- a/.github/workflows/ci-workflow.yml
+++ b/.github/workflows/ci-workflow.yml
@@ -18,9 +18,13 @@ jobs:
   CI:
     name: CI
     runs-on: ubuntu-22.04
+    outputs:
+      shouldUpload: ${{ steps.shouldUpload.outputs.upload }}
     steps:
       - name: Check out repository code
         uses: actions/checkout@v3
+        with:
+          fetch-depth: 0 # check out the entire repo history for SHA verification in lastSuccessful step
 
       - name: Lint specification
         run: make lint
@@ -29,12 +33,34 @@ jobs:
       - name: Render API docs
         run: make render
 
+      #################################
+      ## Upload deployable artefacts ##
+      #################################
+      - name: Identify latest successful run
+        id: lastSuccessful
+        uses: SamhammerAG/last-successful-build-action@1c368a27a90596574a71ac0ede422a897d0e8e84  # @v4
+        with:
+          branch: ${{ github.ref_name }}
+          workflow: ${{ github.workflow }}
+          verify: true
+
+      - name: Determine if this workflow should upload artefacts
+        id: shouldUpload
+        shell: bash
+        run: |
+          if [ "${{ steps.lastSuccessful.outputs.sha }}" != "${{ github.sha }}" ] && [ "${{ github.ref_name }}" == "main" ]
+          then
+            echo "upload=true" >> $GITHUB_OUTPUT;
+          else
+            echo "upload=false" >> $GITHUB_OUTPUT;
+          fi
+
       - name: Setup pages
-        if: ${{ inputs.forceDocsUpload || ( github.ref == 'refs/heads/main' ) }}
+        if: ${{ inputs.forceDocsUpload || ( steps.shouldUpload.outputs.upload == 'true' ) }}
         uses: actions/configure-pages@v3
 
       - name: Upload documentation artifact
-        if: ${{ inputs.forceDocsUpload || ( github.ref == 'refs/heads/main' ) }}
+        if: ${{ inputs.forceDocsUpload || ( steps.shouldUpload.outputs.upload == 'true' ) }}
         uses: actions/upload-pages-artifact@v2
         with:
           path: './api/docs'
@@ -48,7 +74,7 @@ jobs:
       id-token: write
     runs-on: ubuntu-22.04
     needs: CI
-    if: ${{ inputs.forceDocsUpload || ( github.ref == 'refs/heads/main' ) }}
+    if: ${{ inputs.forceDocsUpload || ( needs.CI.outputs.shouldUpload == 'true' ) }}
     steps:
       - name: Deploy documentation to GitHub Pages
         id: deployment

From 1017dca5ad599606207d4ddb1816dbe85519ef2e Mon Sep 17 00:00:00 2001
From: Sam Mesterton-Gibbons <sam.mesterton-gibbons@bbc.co.uk>
Date: Thu, 14 Sep 2023 10:32:11 +0100
Subject: [PATCH 2/3] Slow down CI to only run weekly

---
 .github/workflows/ci-workflow.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci-workflow.yml b/.github/workflows/ci-workflow.yml
index f5b7185..9e3eb34 100644
--- a/.github/workflows/ci-workflow.yml
+++ b/.github/workflows/ci-workflow.yml
@@ -2,7 +2,7 @@ name: CI Workflow
 run-name: ${{ format('{0} triggered {1} on {2}', (github.event_name == 'workflow_dispatch' && format('User {0}', github.actor) || format('{0} event', github.event_name) ), github.workflow, github.ref) }}
 on:
   schedule:
-    - cron: '0 4 * * 1-5'
+    - cron: '0 4 * * 1'
 
   push:
 

From aea23a4586cabf3f5f0163c69fb8b13fd537c006 Mon Sep 17 00:00:00 2001
From: Sam Mesterton-Gibbons <sam.mesterton-gibbons@bbc.co.uk>
Date: Thu, 14 Sep 2023 20:35:46 +0100
Subject: [PATCH 3/3] Only run CI on PRs or push to main

Co-authored-by: James Sandford <james.sandford@bbc.co.uk>
---
 .github/workflows/ci-workflow.yml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/workflows/ci-workflow.yml b/.github/workflows/ci-workflow.yml
index 9e3eb34..3c64b49 100644
--- a/.github/workflows/ci-workflow.yml
+++ b/.github/workflows/ci-workflow.yml
@@ -4,7 +4,11 @@ on:
   schedule:
     - cron: '0 4 * * 1'
 
+  pull_request:
+
   push:
+    branches:
+      - 'main'
 
   workflow_dispatch:
     inputs: