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Be able to synchronize the TTL of cache-control header to expire in a coherent way

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This commit is contained in:
Daniel García Aubert 2019-10-15 12:48:50 +02:00
parent f8e117a7b7
commit 5a7ffcf499
2 changed files with 44 additions and 5 deletions
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35
lib/api/middlewares/cache-control-header.js
View File

@ -1,14 +1,35 @@
'use strict';
const ONE_YEAR_IN_SECONDS = 60 * 60 * 24 * 365;
const FIVE_MINUTES_IN_SECONDS = 60 * 5;
const ONE_MINUTE_IN_SECONDS = 60;
const THREE_MINUTE_IN_SECONDS = 60 * 3;
const FIVE_MINUTES_IN_SECONDS = ONE_MINUTE_IN_SECONDS * 5;
const TEN_MINUTES_IN_SECONDS = ONE_MINUTE_IN_SECONDS * 10;
const FIFTEEN_MINUTES_IN_SECONDS = ONE_MINUTE_IN_SECONDS * 15;
const THIRTY_MINUTES_IN_SECONDS = ONE_MINUTE_IN_SECONDS * 30;
const ONE_HOUR_IN_SECONDS = ONE_MINUTE_IN_SECONDS * 60;
const ONE_YEAR_IN_SECONDS = ONE_HOUR_IN_SECONDS * 24 * 365;
const FALLBACK_TTL = global.environment.varnish.fallbackTtl || FIVE_MINUTES_IN_SECONDS;
const validFallbackTTL = [
ONE_MINUTE_IN_SECONDS,
THREE_MINUTE_IN_SECONDS,
FIVE_MINUTES_IN_SECONDS,
TEN_MINUTES_IN_SECONDS,
FIFTEEN_MINUTES_IN_SECONDS,
THIRTY_MINUTES_IN_SECONDS,
ONE_HOUR_IN_SECONDS
];
module.exports = function setCacheControlHeader ({
ttl = ONE_YEAR_IN_SECONDS,
fallbackTtl = FALLBACK_TTL,
revalidate = false
} = {}) {
if (!validFallbackTTL.includes(fallbackTtl)) {
throw new Error(`Invalid fallback TTL value for Cache-Control header. Got ${fallbackTtl}, expected ${validFallbackTTL.join(', ')}`);
}
return function setCacheControlHeaderMiddleware (req, res, next) {
if (req.method !== 'GET') {
return next();
@ -27,7 +48,7 @@ module.exports = function setCacheControlHeader ({
if (everyAffectedTableCanBeInvalidated(affectedTables)) {
directives.push(`max-age=${ttl}`);
} else {
directives.push(`max-age=${fallbackTtl}`);
directives.push(`max-age=${computeNextTTL({ ttlInSeconds: fallbackTtl })}`);
}
if (revalidate) {
@ -49,3 +70,11 @@ function everyAffectedTableCanBeInvalidated (affectedTables) {
affectedTables.getTables(skipNotUpdatedAtTables, skipAnalysisCachedTables)
.every(table => table.updated_at !== null);
}
function computeNextTTL ({ ttlInSeconds } = {}) {
const nowInSeconds = Math.ceil(Date.now() / 1000);
const secondsAfterPreviousTTLStep = nowInSeconds % ttlInSeconds;
const secondsToReachTheNextTTLStep = ttlInSeconds - secondsAfterPreviousTTLStep;
return secondsToReachTheNextTTLStep;
}

14
test/acceptance/cache/cache-control-header-test.js vendored
View File

@ -79,7 +79,12 @@ describe('cache-control header', function () {
return done(err);
}
assert.equal(res.headers['cache-control'], `public,max-age=${ttl}`);
const cacheControl = res.headers['cache-control'];
const [ type, maxAge ] = cacheControl.split(',');
const [ key, value ] = maxAge.split('=');
assert.ok(Number(value) <= ttl);
testClient.drain(done);
});
});
@ -114,7 +119,12 @@ describe('cache-control header', function () {
return done(err);
}
assert.equal(res.headers['cache-control'], `public,max-age=${ttl}`);
const cacheControl = res.headers['cache-control'];
const [ type, maxAge ] = cacheControl.split(',');
const [ key, value ] = maxAge.split('=');
assert.ok(Number(value) <= ttl);
testClient.drain(done);
});
});