add doclines set/del metric

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

@@ -41,7 +41,7 @@ module.exports = RedisManager =
 			logger.error {err: error, doc_id: doc_id, docLines: docLines}, error.message
 			return callback(error)
 		docHash = RedisManager._computeHash(docLines)
-		metrics.summary "redis.setDoc", docLines.length, {status: "set"}
+		metrics.summary "redis.docLines", docLines.length, {status: "set"}
 		logger.log {project_id, doc_id, version, docHash, pathname, projectHistoryId}, "putting doc in redis"
 		RedisManager._serializeRanges ranges, (error, ranges) ->
 			if error?
@@ -74,6 +74,7 @@ module.exports = RedisManager =
 				_callback()
 
 		multi = rclient.multi()
+		multi.strlen keys.docLines(doc_id:doc_id)
 		multi.del keys.docLines(doc_id:doc_id)
 		multi.del keys.projectKey(doc_id:doc_id)
 		multi.del keys.docVersion(doc_id:doc_id)
@@ -85,8 +86,11 @@ module.exports = RedisManager =
 		multi.del keys.unflushedTime(doc_id:doc_id)
 		multi.del keys.lastUpdatedAt(doc_id: doc_id)
 		multi.del keys.lastUpdatedBy(doc_id: doc_id)
-		multi.exec (error) ->
+		multi.exec (error, response) ->
 			return callback(error) if error?
+			length = response?[0]
+			if length > 0
+				metrics.summary "redis.docLines", length, {status: "del"}
 			multi = rclient.multi()
 			multi.srem keys.docsInProject(project_id:project_id), doc_id
 			multi.del keys.projectState(project_id:project_id)

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

@@ -671,11 +671,17 @@ describe "RedisManager", ->
 
 	describe "removeDocFromMemory", ->
 		beforeEach (done) ->
+			@multi.strlen = sinon.stub()
 			@multi.del = sinon.stub()
 			@multi.srem = sinon.stub()
 			@multi.exec.yields()
 			@RedisManager.removeDocFromMemory @project_id, @doc_id, done
 
+		it "should check the length of the current doclines", ->
+			@multi.strlen
+				.calledWith("doclines:#{@doc_id}")
+				.should.equal true
+
 		it "should delete the lines", ->
 			@multi.del
 				.calledWith("doclines:#{@doc_id}")