Modify the GitHub build schedule to every Sunday

Author: marionbarker

.github/workflows/build_loop.yml

@@ -2,17 +2,10 @@ name: 4. Build Loop
 run-name: Build Loop (${{ github.ref_name }})
 on:
   workflow_dispatch:
-
-  ## Remove the "#" sign from the beginning of the line below to get automated builds on push (code changes in your repository)
-  #push:
-
-  # Automated builds now include automatic certificate update - the nuke certs part of that process could
-  #   affect other OS apps if run simultaneously.
-  # Each OS needs a time of day distinct from other apps, LoopWorkspace uses 9 every Wed and 7 every 1st of month
   schedule:
-    # avoid starting an action at hh:00 when GitHub resources are impacted
-    - cron: "33 9 * * 3" # Checks for updates at 09:33 UTC every Wednesday
-    - cron: "33 7 1 * *" # Builds the app on the 1st of every month at 07:33 UTC
+    # Check for updates every Sunday
+    #   Later logic builds if there are updates or if it is the 2nd Sunday of the month
+    - cron: "33 7 * * 0" # Sunday at UTC 7:33
 
 env:
   UPSTREAM_REPO: LoopKit/LoopWorkspace
@@ -22,6 +15,26 @@ env:
   ALIVE_BRANCH_DEV: alive-dev
 
 jobs:
+
+  # Set a logic flag if this is the second instance of this day-of-week in this month
+  day_in_month:
+    runs-on: ubuntu-latest
+    name: Check day in month
+    outputs:
+      IS_SECOND_IN_MONTH: ${{ steps.date-check.outputs.is_second_instance }}
+
+    steps:
+      - id: date-check
+        name: Check if this is the second time this day-of-week happens this month
+        run: |
+          DAY_OF_MONTH=$(date +%-d)
+          WEEK_OF_MONTH=$(( ($(date +%-d) - 1) / 7 + 1 ))
+          if [[ $WEEK_OF_MONTH -eq 2 ]]; then
+            echo "is_second_instance=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "is_second_instance=false" >> "$GITHUB_OUTPUT"
+          fi
+
   # Checks if Distribution certificate is present and valid, optionally nukes and
   # creates new certs if the repository variable ENABLE_NUKE_CERTS == 'true'
   check_certs: 
@@ -193,15 +206,15 @@ jobs:
   # Builds Loop
   build:
     name: Build
-    needs: [check_certs, check_alive_and_permissions, check_latest_from_upstream]
+    needs: [check_certs, check_alive_and_permissions, check_latest_from_upstream, day_in_month]
     runs-on: macos-15
     permissions:
       contents: write
     if:
-      | # runs if started manually, or if sync schedule is set and enabled and scheduled on the first Saturday each month, or if sync schedule is set and enabled and new commits were found
+      | # builds with manual start; if automatic: once a month or when new commits are found
       github.event_name == 'workflow_dispatch' ||
       (needs.check_alive_and_permissions.outputs.WORKFLOW_PERMISSION == 'true' &&
-        (vars.SCHEDULED_BUILD != 'false' && github.event.schedule == '33 7 1 * *') ||
+        (vars.SCHEDULED_BUILD != 'false' && needs.day_in_month.outputs.IS_SECOND_IN_MONTH == 'true') ||
         (vars.SCHEDULED_SYNC != 'false' && needs.check_latest_from_upstream.outputs.NEW_COMMITS == 'true' )
       )
     steps:
@@ -334,4 +347,4 @@ jobs:
           name: build-artifacts
           path: |
             artifacts
-            buildlog
+            buildlog