Canary: Post-Deploy Monitoring

Watch a live application after deployment. Alert on errors and regressions. Compare against a pre-deploy baseline.

Two modes:

• --baseline: capture the current state BEFORE deploying
• (default): monitor AFTER deploying and compare against baseline

Instructions

Phase 1: Setup

Parse the user's arguments and detect the deployment context.

# Detect current branch and recent deploy commit
git branch --show-current
git log --oneline -5

# Auto-detect platform from config files
[ -f fly.toml ]         && echo "PLATFORM: fly"
[ -f render.yaml ]      && echo "PLATFORM: render"
[ -f vercel.json ]      && echo "PLATFORM: vercel"
[ -f netlify.toml ]     && echo "PLATFORM: netlify"
[ -f Procfile ]         && echo "PLATFORM: heroku"
[ -f railway.toml ]     && echo "PLATFORM: railway"

# Check for health endpoint
curl -sf "${URL}/health" -w "\n%{http_code}" 2>/dev/null | tail -1
curl -sf "${URL}/api/health" -w "\n%{http_code}" 2>/dev/null | tail -1

Create the working directory:

mkdir -p .canary/baselines .canary/reports .canary/screenshots

---

Phase 2: Baseline Capture (--baseline mode)

Run this BEFORE deploying to capture the current healthy state.

For each page to monitor, record:

1. HTTP status: is the page returning 200?
2. Response time: how long does it take to load?
3. Content snapshot: key text content to detect blank pages later

# For each page URL
for PAGE_PATH in "/" "/dashboard" "/settings" "/api/health"; do
  SLUG=$(echo "$PAGE_PATH" | tr '/' '_' | tr -d '?&=')
  RESULT=$(curl -sf -o /dev/null -w "%{http_code}|%{time_total}" "${BASE_URL}${PAGE_PATH}" 2>/dev/null)
  STATUS=$(echo "$RESULT" | cut -d'|' -f1)
  TIME_MS=$(echo "$RESULT" | awk -F'|' '{printf "%.0f", $2 * 1000}')
  echo "  ${PAGE_PATH}: HTTP ${STATUS}, ${TIME_MS}ms"
done

Save baseline to .canary/baselines/baseline.json:

{