overleaf/services/filestore/app/js/MigrationPersistor.js
2020-04-15 12:22:54 +01:00

230 lines
7.3 KiB
JavaScript

const metrics = require('metrics-sharelatex')
const Settings = require('settings-sharelatex')
const logger = require('logger-sharelatex')
const Stream = require('stream')
const { callbackify, promisify } = require('util')
const { NotFoundError, WriteError } = require('./Errors')
const pipeline = promisify(Stream.pipeline)
// Persistor that wraps two other persistors. Talks to the 'primary' by default,
// but will fall back to an older persistor in the case of a not-found error.
// If `Settings.filestore.fallback.copyOnMiss` is set, this will copy files from the fallback
// to the primary, in the event that they are missing.
//
// It is unlikely that the bucket/location name will be the same on the fallback
// as the primary. The bucket names should be overridden in `Settings.filestore.fallback.buckets`
// e.g.
// Settings.filestore.fallback.buckets = {
// myBucketOnS3: 'myBucketOnGCS'
// }
module.exports = function(primary, fallback) {
function _wrapMethodOnBothPersistors(method) {
return async function(bucket, key, ...moreArgs) {
const fallbackBucket = _getFallbackBucket(bucket)
await Promise.all([
primary.promises[method](bucket, key, ...moreArgs),
fallback.promises[method](fallbackBucket, key, ...moreArgs)
])
}
}
async function getFileStreamWithFallback(bucket, key, opts) {
const shouldCopy =
Settings.filestore.fallback.copyOnMiss && !opts.start && !opts.end
try {
return await primary.promises.getFileStream(bucket, key, opts)
} catch (err) {
if (err instanceof NotFoundError) {
const fallbackBucket = _getFallbackBucket(bucket)
const fallbackStream = await fallback.promises.getFileStream(
fallbackBucket,
key,
opts
)
// tee the stream to the client, and as a copy to the primary (if necessary)
// start listening on both straight away so that we don't consume bytes
// in one place before the other
const returnStream = new Stream.PassThrough()
pipeline(fallbackStream, returnStream)
if (shouldCopy) {
const copyStream = new Stream.PassThrough()
pipeline(fallbackStream, copyStream)
_copyStreamFromFallbackAndVerify(
copyStream,
fallbackBucket,
bucket,
key,
key
).catch(() => {
// swallow errors, as this runs in the background and will log a warning
})
}
return returnStream
}
throw err
}
}
async function copyFileWithFallback(bucket, sourceKey, destKey) {
try {
return await primary.promises.copyFile(bucket, sourceKey, destKey)
} catch (err) {
if (err instanceof NotFoundError) {
const fallbackBucket = _getFallbackBucket(bucket)
const fallbackStream = await fallback.promises.getFileStream(
fallbackBucket,
sourceKey,
{}
)
const copyStream = new Stream.PassThrough()
pipeline(fallbackStream, copyStream)
if (Settings.filestore.fallback.copyOnMiss) {
const missStream = new Stream.PassThrough()
pipeline(fallbackStream, missStream)
// copy from sourceKey -> sourceKey
_copyStreamFromFallbackAndVerify(
missStream,
fallbackBucket,
bucket,
sourceKey,
sourceKey
).then(() => {
// swallow errors, as this runs in the background and will log a warning
})
}
// copy from sourceKey -> destKey
return _copyStreamFromFallbackAndVerify(
copyStream,
fallbackBucket,
bucket,
sourceKey,
destKey
)
}
throw err
}
}
function _getFallbackBucket(bucket) {
return Settings.filestore.fallback.buckets[bucket] || bucket
}
function _wrapFallbackMethod(method) {
return async function(bucket, key, ...moreArgs) {
try {
return await primary.promises[method](bucket, key, ...moreArgs)
} catch (err) {
if (err instanceof NotFoundError) {
const fallbackBucket = _getFallbackBucket(bucket)
if (Settings.filestore.fallback.copyOnMiss) {
const fallbackStream = await fallback.promises.getFileStream(
fallbackBucket,
key,
{}
)
// run in background
_copyStreamFromFallbackAndVerify(
fallbackStream,
fallbackBucket,
bucket,
key,
key
).catch(err => {
logger.warn({ err }, 'failed to copy file from fallback')
})
}
return fallback.promises[method](fallbackBucket, key, ...moreArgs)
}
throw err
}
}
}
async function _copyStreamFromFallbackAndVerify(
stream,
sourceBucket,
destBucket,
sourceKey,
destKey
) {
try {
let sourceMd5
try {
sourceMd5 = await fallback.promises.getFileMd5Hash(
sourceBucket,
sourceKey
)
} catch (err) {
logger.warn(err, 'error getting md5 hash from fallback persistor')
}
await primary.promises.sendStream(destBucket, destKey, stream, sourceMd5)
} catch (err) {
const error = new WriteError({
message: 'unable to copy file to destination persistor',
info: {
sourceBucket,
destBucket,
sourceKey,
destKey
}
}).withCause(err)
metrics.inc('fallback.copy.failure')
try {
await primary.promises.deleteFile(destBucket, destKey)
} catch (err) {
error.info.cleanupError = new WriteError({
message: 'unable to clean up destination copy artifact',
info: {
destBucket,
destKey
}
}).withCause(err)
}
logger.warn({ error }, 'failed to copy file from fallback')
throw error
}
}
return {
primaryPersistor: primary,
fallbackPersistor: fallback,
sendFile: primary.sendFile,
sendStream: primary.sendStream,
getFileStream: callbackify(getFileStreamWithFallback),
getRedirectUrl: primary.getRedirectUrl,
getFileMd5Hash: callbackify(_wrapFallbackMethod('getFileMd5Hash')),
deleteDirectory: callbackify(
_wrapMethodOnBothPersistors('deleteDirectory')
),
getFileSize: callbackify(_wrapFallbackMethod('getFileSize')),
deleteFile: callbackify(_wrapMethodOnBothPersistors('deleteFile')),
copyFile: callbackify(copyFileWithFallback),
checkIfFileExists: callbackify(_wrapFallbackMethod('checkIfFileExists')),
directorySize: callbackify(_wrapFallbackMethod('directorySize')),
promises: {
sendFile: primary.promises.sendFile,
sendStream: primary.promises.sendStream,
getFileStream: getFileStreamWithFallback,
getRedirectUrl: primary.promises.getRedirectUrl,
getFileMd5Hash: _wrapFallbackMethod('getFileMd5Hash'),
deleteDirectory: _wrapMethodOnBothPersistors('deleteDirectory'),
getFileSize: _wrapFallbackMethod('getFileSize'),
deleteFile: _wrapMethodOnBothPersistors('deleteFile'),
copyFile: copyFileWithFallback,
checkIfFileExists: _wrapFallbackMethod('checkIfFileExists'),
directorySize: _wrapFallbackMethod('directorySize')
}
}
}