Settings = require('settings-sharelatex') async = require('async') rclient = require("redis-sharelatex").createClient(Settings.redis.documentupdater) _ = require('underscore') logger = require('logger-sharelatex') metrics = require('./Metrics') Errors = require "./Errors" crypto = require "crypto" # Sometimes Redis calls take an unexpectedly long time. We have to be # quick with Redis calls because we're holding a lock that expires # after 30 seconds. We can't let any errors in the rest of the stack # hold us up, and need to bail out quickly if there is a problem. MAX_REDIS_REQUEST_LENGTH = 5000 # 5 seconds # Make times easy to read minutes = 60 # seconds for Redis expire # LUA script to write document and return hash # arguments: docLinesKey docLines setScript = """ redis.call('set', KEYS[1], ARGV[1]) return redis.sha1hex(ARGV[1]) """ logHashErrors = Settings.documentupdater?.logHashErrors logHashReadErrors = logHashErrors?.read logHashWriteErrors = logHashErrors?.write MEGABYTES = 1024 * 1024 MAX_RANGES_SIZE = 3 * MEGABYTES keys = Settings.redis.documentupdater.key_schema historyKeys = Settings.redis.history.key_schema module.exports = RedisManager = rclient: rclient putDocInMemory : (project_id, doc_id, docLines, version, ranges, _callback)-> timer = new metrics.Timer("redis.put-doc") callback = (error) -> timer.done() _callback(error) docLines = JSON.stringify(docLines) if docLines.indexOf("\u0000") != -1 error = new Error("null bytes found in doc lines") logger.error err: error, doc_id: doc_id, docLines: docLines, error.message return callback(error) docHash = RedisManager._computeHash(docLines) logger.log project_id:project_id, doc_id:doc_id, version: version, hash:docHash, "putting doc in redis" RedisManager._serializeRanges ranges, (error, ranges) -> if error? logger.error {err: error, doc_id, project_id}, error.message return callback(error) multi = rclient.multi() multi.eval setScript, 1, keys.docLines(doc_id:doc_id), docLines multi.set keys.projectKey({doc_id:doc_id}), project_id multi.set keys.docVersion(doc_id:doc_id), version multi.set keys.docHash(doc_id:doc_id), docHash if ranges? multi.set keys.ranges(doc_id:doc_id), ranges else multi.del keys.ranges(doc_id:doc_id) multi.exec (error, result) -> return callback(error) if error? # check the hash computed on the redis server writeHash = result?[0] if logHashWriteErrors and writeHash? and writeHash isnt docHash logger.error project_id: project_id, doc_id: doc_id, writeHash: writeHash, origHash: docHash, docLines:docLines, "hash mismatch on putDocInMemory" # update docsInProject set rclient.sadd keys.docsInProject(project_id:project_id), doc_id, callback removeDocFromMemory : (project_id, doc_id, _callback)-> logger.log project_id:project_id, doc_id:doc_id, "removing doc from redis" callback = (err) -> if err? logger.err project_id:project_id, doc_id:doc_id, err:err, "error removing doc from redis" _callback(err) else logger.log project_id:project_id, doc_id:doc_id, "removed doc from redis" _callback() multi = rclient.multi() multi.del keys.docLines(doc_id:doc_id) multi.del keys.projectKey(doc_id:doc_id) multi.del keys.docVersion(doc_id:doc_id) multi.del keys.docHash(doc_id:doc_id) multi.del keys.ranges(doc_id:doc_id) multi.exec (error) -> return callback(error) if error? rclient.srem keys.docsInProject(project_id:project_id), doc_id, callback getDoc : (project_id, doc_id, callback = (error, lines, version, ranges) ->)-> timer = new metrics.Timer("redis.get-doc") multi = rclient.multi() multi.get keys.docLines(doc_id:doc_id) multi.get keys.docVersion(doc_id:doc_id) multi.get keys.docHash(doc_id:doc_id) multi.get keys.projectKey(doc_id:doc_id) multi.get keys.ranges(doc_id:doc_id) multi.exec (error, [docLines, version, storedHash, doc_project_id, ranges])-> timeSpan = timer.done() return callback(error) if error? # check if request took too long and bail out. only do this for # get, because it is the first call in each update, so if this # passes we'll assume others have a reasonable chance to succeed. if timeSpan > MAX_REDIS_REQUEST_LENGTH error = new Error("redis getDoc exceeded timeout") return callback(error) # check sha1 hash value if present if docLines? and storedHash? computedHash = RedisManager._computeHash(docLines) if logHashReadErrors and computedHash isnt storedHash logger.error project_id: project_id, doc_id: doc_id, doc_project_id: doc_project_id, computedHash: computedHash, storedHash: storedHash, docLines:docLines, "hash mismatch on retrieved document" try docLines = JSON.parse docLines ranges = RedisManager._deserializeRanges(ranges) catch e return callback(e) version = parseInt(version or 0, 10) # check doc is in requested project if doc_project_id? and doc_project_id isnt project_id logger.error project_id: project_id, doc_id: doc_id, doc_project_id: doc_project_id, "doc not in project" return callback(new Errors.NotFoundError("document not found")) # doc is not in redis, bail out if !docLines? return callback null, docLines, version, ranges # doc should be in project set, check if missing (workaround for missing docs from putDoc) rclient.sadd keys.docsInProject(project_id:project_id), doc_id, (error, result) -> return callback(error) if error? if result isnt 0 # doc should already be in set logger.error project_id: project_id, doc_id: doc_id, doc_project_id: doc_project_id, "doc missing from docsInProject set" callback null, docLines, version, ranges getDocVersion: (doc_id, callback = (error, version) ->) -> rclient.get keys.docVersion(doc_id: doc_id), (error, version) -> return callback(error) if error? version = parseInt(version, 10) callback null, version getDocLines: (doc_id, callback = (error, version) ->) -> rclient.get keys.docLines(doc_id: doc_id), (error, docLines) -> return callback(error) if error? callback null, docLines getPreviousDocOps: (doc_id, start, end, callback = (error, jsonOps) ->) -> timer = new metrics.Timer("redis.get-prev-docops") rclient.llen keys.docOps(doc_id: doc_id), (error, length) -> return callback(error) if error? rclient.get keys.docVersion(doc_id: doc_id), (error, version) -> return callback(error) if error? version = parseInt(version, 10) first_version_in_redis = version - length if start < first_version_in_redis or end > version error = new Errors.OpRangeNotAvailableError("doc ops range is not loaded in redis") logger.warn {err: error, doc_id, length, version, start, end}, "doc ops range is not loaded in redis" return callback(error) start = start - first_version_in_redis if end > -1 end = end - first_version_in_redis if isNaN(start) or isNaN(end) error = new Error("inconsistent version or lengths") logger.error {err: error, doc_id, length, version, start, end}, "inconsistent version or length" return callback(error) rclient.lrange keys.docOps(doc_id: doc_id), start, end, (error, jsonOps) -> return callback(error) if error? try ops = jsonOps.map (jsonOp) -> JSON.parse jsonOp catch e return callback(e) timeSpan = timer.done() if timeSpan > MAX_REDIS_REQUEST_LENGTH error = new Error("redis getPreviousDocOps exceeded timeout") return callback(error) callback null, ops DOC_OPS_TTL: 60 * minutes DOC_OPS_MAX_LENGTH: 100 updateDocument : (doc_id, docLines, newVersion, appliedOps = [], ranges, callback = (error) ->)-> RedisManager.getDocVersion doc_id, (error, currentVersion) -> return callback(error) if error? if currentVersion + appliedOps.length != newVersion error = new Error("Version mismatch. '#{doc_id}' is corrupted.") logger.error {err: error, doc_id, currentVersion, newVersion, opsLength: appliedOps.length}, "version mismatch" return callback(error) jsonOps = appliedOps.map (op) -> JSON.stringify op for op in jsonOps if op.indexOf("\u0000") != -1 error = new Error("null bytes found in jsonOps") logger.error err: error, doc_id: doc_id, jsonOps: jsonOps, error.message return callback(error) newDocLines = JSON.stringify(docLines) if newDocLines.indexOf("\u0000") != -1 error = new Error("null bytes found in doc lines") logger.error err: error, doc_id: doc_id, newDocLines: newDocLines, error.message return callback(error) newHash = RedisManager._computeHash(newDocLines) opVersions = appliedOps.map (op) -> op?.v logger.log doc_id: doc_id, version: newVersion, hash: newHash, op_versions: opVersions, "updating doc in redis" RedisManager._serializeRanges ranges, (error, ranges) -> if error? logger.error {err: error, doc_id}, error.message return callback(error) if ranges? and ranges.indexOf("\u0000") != -1 error = new Error("null bytes found in ranges") logger.error err: error, doc_id: doc_id, ranges: ranges, error.message return callback(error) multi = rclient.multi() multi.eval setScript, 1, keys.docLines(doc_id:doc_id), newDocLines # index 0 multi.set keys.docVersion(doc_id:doc_id), newVersion # index 1 multi.set keys.docHash(doc_id:doc_id), newHash # index 2 multi.ltrim keys.docOps(doc_id: doc_id), -RedisManager.DOC_OPS_MAX_LENGTH, -1 # index 3 if ranges? multi.set keys.ranges(doc_id:doc_id), ranges # index 4 else multi.del keys.ranges(doc_id:doc_id) # also index 4 # push the ops last so we can get the lengths at fixed index position 7 if jsonOps.length > 0 multi.rpush keys.docOps(doc_id: doc_id), jsonOps... # index 5 # expire must come after rpush since before it will be a no-op if the list is empty multi.expire keys.docOps(doc_id: doc_id), RedisManager.DOC_OPS_TTL # index 6 multi.rpush historyKeys.uncompressedHistoryOps(doc_id: doc_id), jsonOps... # index 7 multi.exec (error, result) -> return callback(error) if error? # check the hash computed on the redis server writeHash = result?[0] if logHashWriteErrors and writeHash? and writeHash isnt newHash logger.error doc_id: doc_id, writeHash: writeHash, origHash: newHash, docLines:newDocLines, "hash mismatch on updateDocument" # return length of uncompressedHistoryOps queue (index 7) uncompressedHistoryOpsLength = result?[7] return callback(null, uncompressedHistoryOpsLength) getDocIdsInProject: (project_id, callback = (error, doc_ids) ->) -> rclient.smembers keys.docsInProject(project_id: project_id), callback _serializeRanges: (ranges, callback = (error, serializedRanges) ->) -> jsonRanges = JSON.stringify(ranges) if jsonRanges? and jsonRanges.length > MAX_RANGES_SIZE return callback new Error("ranges are too large") if jsonRanges == '{}' # Most doc will have empty ranges so don't fill redis with lots of '{}' keys jsonRanges = null return callback null, jsonRanges _deserializeRanges: (ranges) -> if !ranges? or ranges == "" return {} else return JSON.parse(ranges) _computeHash: (docLines) -> # use sha1 checksum of doclines to detect data corruption. # # note: must specify 'utf8' encoding explicitly, as the default is # binary in node < v5 return crypto.createHash('sha1').update(docLines, 'utf8').digest('hex')