[build] Add weekly CI check for Plausible pageview usage

.github/workflows/plausible-usage.yml

@@ -0,0 +1,34 @@
+name: Plausible Usage
+on:
+  schedule:
+    - cron: 30 12 * * 3
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    name: Check Weekly Pageviews
+    runs-on: ubuntu-latest
+    if: github.event.repository.fork == false
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - name: Check Plausible Pageviews
+        id: check
+        env:
+          PLAUSIBLE_STATS_KEY: ${{ secrets.PLAUSIBLE_STATS_KEY }}
+        run: ./scripts/github-actions/check-plausible-usage.sh
+      - name: Slack Notification
+        if: failure()
+        uses: rtCamp/action-slack-notify@v2
+        env:
+          SLACK_ICON_EMOJI: ":rotating_light:"
+          SLACK_COLOR: failure
+          SLACK_CHANNEL: selenium-tlc
+          SLACK_USERNAME: GitHub Workflows
+          SLACK_MESSAGE: ${{ steps.check.outputs.report || 'Plausible stats could not be read for last week' }}
+          MSG_MINIMAL: actions url
+          SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK_URL }}

scripts/github-actions/check-plausible-usage.sh

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+#!/usr/bin/env bash
+#
+# Fail when Plausible pageviews for the last seven complete days exceed a threshold.
+#
+# Selenium Manager telemetry is billed against a Plausible plan, and sustained
+# overage locks the dashboard, so we watch the trailing week and raise an alarm
+# with enough headroom to react.
+#
+# Requires PLAUSIBLE_STATS_KEY. PLAUSIBLE_SITE_ID, PLAUSIBLE_THRESHOLD and
+# PLAUSIBLE_MONTHLY_LIMIT may be set to override the defaults.
+
+set -euo pipefail
+
+SITE_ID="${PLAUSIBLE_SITE_ID:-manager.selenium.dev}"
+THRESHOLD="${PLAUSIBLE_THRESHOLD:-17000000}"
+MONTHLY_LIMIT="${PLAUSIBLE_MONTHLY_LIMIT:-75000000}"
+
+: "${PLAUSIBLE_STATS_KEY:?PLAUSIBLE_STATS_KEY is required}"
+
+millions() {
+  awk -v n="$1" 'BEGIN { v = n / 1000000; printf (v == int(v) ? "%d" : "%.1f"), v }'
+}
+
+# Yesterday back six days; Plausible's period=7d rolls into today's partial data.
+if date -u -d 'yesterday' +%F >/dev/null 2>&1; then
+  END="$(date -u -d 'yesterday' +%F)"
+  START="$(date -u -d '7 days ago' +%F)"
+else # BSD/macOS date
+  END="$(date -u -v-1d +%F)"
+  START="$(date -u -v-7d +%F)"
+fi
+
+echo "Site:      ${SITE_ID}"
+echo "Window:    ${START} to ${END}"
+echo "Threshold: $(millions "$THRESHOLD")M per week, $(millions "$MONTHLY_LIMIT")M per month"
+
+# The status code is appended so a 4xx body reaches the log instead of being
+# swallowed by the failing assignment.
+if ! response="$(curl --silent --show-error --write-out '\n%{http_code}' \
+  --get "https://plausible.io/api/v1/stats/aggregate" \
+  --header "Authorization: Bearer ${PLAUSIBLE_STATS_KEY}" \
+  --data-urlencode "site_id=${SITE_ID}" \
+  --data-urlencode "period=custom" \
+  --data-urlencode "date=${START},${END}" \
+  --data-urlencode "metrics=pageviews")"; then
+  echo "::error::Could not reach the Plausible API"
+  exit 1
+fi
+
+http_code="${response##*$'\n'}"
+body="${response%$'\n'*}"
+
+echo "Response:  HTTP ${http_code} ${body}"
+
+if [[ "$http_code" != 200 ]]; then
+  echo "::error::Plausible API returned HTTP ${http_code}"
+  exit 1
+fi
+
+pageviews="$(jq -r '.results.pageviews.value // empty' <<<"$body" 2>/dev/null || true)"
+
+if [[ ! "$pageviews" =~ ^[0-9]+$ ]]; then
+  echo "::error::No pageviews value in the Plausible response"
+  exit 1
+fi
+
+over=false
+direction=under
+if ((pageviews > THRESHOLD)); then
+  over=true
+  direction=over
+fi
+
+monthly="$(awk -v p="$pageviews" 'BEGIN { printf "%d", p / 7 * 30 }')"
+percent="$(awk -v p="$pageviews" -v t="$THRESHOLD" 'BEGIN { printf "%.0f", (p - t) / t * 100 }')"
+
+report="Plausible stats are ${percent#-}% ${direction} budget for last week"
+
+echo "$report"
+echo "On pace for $(millions "$monthly")M this month, against a $(millions "$MONTHLY_LIMIT")M limit"
+
+if [[ -n "${GITHUB_OUTPUT:-}" ]]; then
+  {
+    echo "pageviews=${pageviews}"
+    echo "percent=${percent#-}"
+    echo "monthly=${monthly}"
+    echo "start=${START}"
+    echo "end=${END}"
+    echo "over=${over}"
+    echo "report=${report}"
+  } >>"$GITHUB_OUTPUT"
+fi
+
+if [[ -n "${GITHUB_STEP_SUMMARY:-}" ]]; then
+  echo "$report" >>"$GITHUB_STEP_SUMMARY"
+fi
+
+if [[ "$over" == true ]]; then
+  echo "::error::${report}"
+  exit 1
+fi