76 lines
2.6 KiB
JavaScript
76 lines
2.6 KiB
JavaScript
import got from 'got'
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// Because we use Origin Shielding, it's recommended that you purge twice
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// so it purges the edge nodes *and* the origin.
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// The documentation says:
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//
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// One solution to this race condition problem is simply to purge
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// twice. For purge-all operations, the two purges should be
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// around 30 seconds apart and, for single object and surrogate
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// key purges, around 2 seconds apart.
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//
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// See https://developer.fastly.com/learning/concepts/purging/#shielding
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const DELAY_BEFORE_FIRST_PURGE = 5 * 1000
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const DELAY_BEFORE_SECOND_PURGE = 30 * 1000
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const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms))
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async function purgeFastlyBySurrogateKey({ apiToken, serviceId, surrogateKey }) {
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const safeServiceId = encodeURIComponent(serviceId)
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const headers = {
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'fastly-key': apiToken,
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accept: 'application/json',
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'fastly-soft-purge': '1',
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}
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const requestPath = `https://api.fastly.com/service/${safeServiceId}/purge/${surrogateKey}`
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return got.post(requestPath, { headers, json: true })
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}
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export default async function purgeEdgeCache(
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surrogateKey,
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{
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purgeTwice = true,
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delayBeforeFirstPurge = DELAY_BEFORE_FIRST_PURGE,
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delayBeforeSecondPurge = DELAY_BEFORE_SECOND_PURGE,
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} = {}
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) {
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if (!surrogateKey) {
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throw new Error('No key set and/or no FASTLY_SURROGATE_KEY env var set')
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}
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console.log(`Fastly purgeEdgeCache initialized for: '${surrogateKey}'`)
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const { FASTLY_TOKEN, FASTLY_SERVICE_ID } = process.env
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if (!FASTLY_TOKEN || !FASTLY_SERVICE_ID) {
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throw new Error('Fastly env vars not detected; skipping purgeEdgeCache step')
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}
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const purgingParams = {
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apiToken: FASTLY_TOKEN,
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serviceId: FASTLY_SERVICE_ID,
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surrogateKey,
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}
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// Give the app some extra time to wake up before the thundering herd of
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// Fastly requests.
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if (delayBeforeFirstPurge) {
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console.log('Waiting extra time to prevent a Thundering Herd problem...')
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await sleep(delayBeforeFirstPurge)
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}
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console.log('Attempting first Fastly purge...')
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const firstPurge = await purgeFastlyBySurrogateKey(purgingParams)
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console.log('First Fastly purge result:', firstPurge.body || firstPurge)
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// Evidence has shown that it's necessary to purge twice to ensure all
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// customers see fresh content.
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if (purgeTwice) {
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console.log('Waiting to purge a second time...')
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await sleep(delayBeforeSecondPurge)
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console.log('Attempting second Fastly purge...')
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const secondPurge = await purgeFastlyBySurrogateKey(purgingParams)
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console.log('Second Fastly purge result:', secondPurge.body || secondPurge)
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}
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}
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