Function handler

packages/engine/src/lib/aws/cloudfrontRoutingFunction.js:9–33

* * Data in KV will be, * `name:routing` -> `{ "paths": { "/*": { "originId": "marzgentc-dev-alb-origin", "originType": "alb" } } }`

(event)

 */

async function handler(event) {
  // This is added at deploy time and is immutable after the function is created
  const kvName = `marzgentc:routing`
  // Get request details
  var request = event.request
  var uri = request.uri

  // Try to find a matching route in the KV store
  var routeData = null
  try {
    const kvsHandle = cf.kvs()
    routeData = await kvsHandle.get(kvName, { format: 'json' })
  } catch (e) {
    // KV lookup failed, fallback to default
    console.log('KV lookup error: ' + e.message)
  }

  if (routeData && routeData.paths) {
    const matchingPath = findMatchingPath(uri, routeData.paths)
    if (matchingPath) {
      updateOrigin(request, routeData.paths[matchingPath])
    }
  }
  return request
}

// Find the path pattern that matches the request URI
function findMatchingPath(uri, paths) {