Add in an absolute size limit on the ranges JSON object

services/document-updater/app/coffee/RedisManager.coffee

@@ -22,6 +22,9 @@ logHashErrors = Settings.documentupdater?.logHashErrors
 logHashReadErrors = logHashErrors?.read
 logHashWriteErrors = logHashErrors?.write
 
+MEGABYTES = 1024 * 1024
+MAX_RANGES_SIZE = 3 * MEGABYTES
+
 module.exports = RedisManager =
 	rclient: rclient
 
@@ -37,7 +40,11 @@ module.exports = RedisManager =
 			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"
-		ranges = RedisManager._serializeRanges(ranges)
+
+		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
@@ -163,6 +170,10 @@ module.exports = RedisManager =
 			
 			logger.log doc_id: doc_id, version: newVersion, hash: newHash, "updating doc in redis"
 			
+			RedisManager._serializeRanges ranges, (error, ranges) ->
+				if error?
+					logger.error {err: error, doc_id}, error.message
+					return callback(error)
 				multi = rclient.multi()
 				multi.eval setScript, 1, keys.docLines(doc_id:doc_id), newDocLines
 				multi.set    keys.docVersion(doc_id:doc_id), newVersion
@@ -171,7 +182,6 @@ module.exports = RedisManager =
 					multi.rpush  keys.docOps(doc_id: doc_id), jsonOps...
 				multi.expire keys.docOps(doc_id: doc_id), RedisManager.DOC_OPS_TTL
 				multi.ltrim  keys.docOps(doc_id: doc_id), -RedisManager.DOC_OPS_MAX_LENGTH, -1
-			ranges = RedisManager._serializeRanges(ranges)
 				if ranges?
 					multi.set keys.ranges(doc_id:doc_id), ranges
 				else
@@ -187,12 +197,14 @@ module.exports = RedisManager =
 	getDocIdsInProject: (project_id, callback = (error, doc_ids) ->) ->
 		rclient.smembers keys.docsInProject(project_id: project_id), callback
 	
-	_serializeRanges: (ranges) ->
+	_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 jsonRanges
+		return callback null, jsonRanges
 	
 	_deserializeRanges: (ranges) ->
 		if !ranges? or ranges == ""

services/document-updater/test/acceptance/coffee/RangesTests.coffee

@@ -265,3 +265,40 @@ describe "Ranges", ->
 					throw error if error?
 					expect(data.ranges.comments).to.be.undefined
 					done()
+					
+	describe "tripping range size limit", ->
+		before (done) ->
+			@project_id = DocUpdaterClient.randomId()
+			@user_id = DocUpdaterClient.randomId()
+			@id_seed = DocUpdaterClient.randomId()
+			@doc = {
+				id: DocUpdaterClient.randomId()
+				lines: ["aaa"]
+			}
+			@i = new Array(3 * 1024 * 1024).join("a")
+			@updates = [{
+				doc: @doc.id
+				op: [{ i: @i, p: 1 }]
+				v: 0
+				meta: { user_id: @user_id, tc: @id_seed }
+			}]
+			MockWebApi.insertDoc @project_id, @doc.id, {
+				lines: @doc.lines
+				version: 0
+			}
+			jobs = []
+			for update in @updates
+				do (update) =>
+					jobs.push (callback) => DocUpdaterClient.sendUpdate @project_id, @doc.id, update, callback
+			DocUpdaterClient.preloadDoc @project_id, @doc.id, (error) =>
+				throw error if error?
+				async.series jobs, (error) ->
+					throw error if error?
+					setTimeout done, 200
+		
+		it "should not update the ranges", (done) ->
+			DocUpdaterClient.getDoc @project_id, @doc.id, (error, res, data) =>
+				throw error if error?
+				ranges = data.ranges
+				expect(ranges.changes).to.be.undefined
+				done()

services/document-updater/test/unit/coffee/RedisManager/RedisManagerTests.coffee

@@ -338,6 +338,18 @@ describe "RedisManager", ->
 			it "should call the callback with an error", ->
 				@callback.calledWith(new Error("null bytes found in doc lines")).should.equal true
 	
+		describe "with ranges that are too big", ->
+			beforeEach ->
+				@RedisManager.getDocVersion.withArgs(@doc_id).yields(null, @version - @ops.length)
+				@RedisManager._serializeRanges = sinon.stub().yields(new Error("ranges are too large"))
+				@RedisManager.updateDocument @doc_id, @lines, @version, @ops, @ranges, @callback
+
+			it 'should log an error', ->
+				@logger.error.called.should.equal true
+
+			it "should call the callback with the error", ->
+				@callback.calledWith(new Error("ranges are too large")).should.equal true
+
 	describe "putDocInMemory", ->
 		beforeEach ->
 			@rclient.set = sinon.stub()
@@ -426,6 +438,17 @@ describe "RedisManager", ->
 			it "should call the callback with an error", ->
 				@callback.calledWith(new Error("null bytes found in doc lines")).should.equal true
 	
+		describe "with ranges that are too big", ->
+			beforeEach ->
+				@RedisManager._serializeRanges = sinon.stub().yields(new Error("ranges are too large"))
+				@RedisManager.putDocInMemory @project_id, @doc_id, @lines, @version, @ranges, @callback
+
+			it 'should log an error', ->
+				@logger.error.called.should.equal true
+
+			it "should call the callback with the error", ->
+				@callback.calledWith(new Error("ranges are too large")).should.equal true
+
 	describe "removeDocFromMemory", ->
 		beforeEach (done) ->
 			@rclient.del = sinon.stub()