added docker runner into core codebase

supports both local command runner and docker runner

added docker files for tex live

also fixed tests so they exit correctly & removed debug lines

app/coffee/DockerLockManager.coffee

@@ -0,0 +1,56 @@
+logger = require "logger-sharelatex"
+
+LockState = {} # locks for docker container operations, by container name
+
+module.exports = LockManager =
+
+	MAX_LOCK_HOLD_TIME: 15000  # how long we can keep a lock
+	MAX_LOCK_WAIT_TIME: 10000  # how long we wait for a lock
+	LOCK_TEST_INTERVAL: 1000   # retry time
+
+	tryLock: (key, callback = (err, gotLock) ->) ->
+		existingLock = LockState[key]
+		if existingLock? # the lock is already taken, check how old it is
+			lockAge = Date.now() - existingLock.created
+			if lockAge < LockManager.MAX_LOCK_HOLD_TIME
+				return callback(null, false) # we didn't get the lock, bail out
+			else
+				logger.error {key: key, lock: existingLock, age:lockAge}, "taking old lock by force"
+		# take the lock
+		LockState[key] = lockValue = {created: Date.now()}
+		callback(null, true, lockValue)
+
+	getLock: (key, callback = (error, lockValue) ->) ->
+		startTime = Date.now()
+		do attempt = () ->
+			LockManager.tryLock key, (error, gotLock, lockValue) ->
+				return callback(error) if error?
+				if gotLock
+					callback(null, lockValue)
+				else if Date.now() - startTime > LockManager.MAX_LOCK_WAIT_TIME
+					e = new Error("Lock timeout")
+					e.key = key
+					return callback(e)
+				else
+					setTimeout attempt, LockManager.LOCK_TEST_INTERVAL
+
+	releaseLock: (key, lockValue, callback = (error) ->) ->
+		existingLock = LockState[key]
+		if existingLock is lockValue # lockValue is an object, so we can test by reference
+			delete LockState[key] # our lock, so we can free it
+			callback()
+		else if existingLock? # lock exists but doesn't match ours
+			logger.error {key:key, lock: existingLock}, "tried to release lock taken by force"
+			callback()
+		else
+			logger.error {key:key, lock: existingLock}, "tried to release lock that has gone"
+			callback()
+
+	runWithLock: (key, runner = ( (releaseLock = (error) ->) -> ), callback = ( (error) -> )) ->
+		LockManager.getLock key, (error, lockValue) ->
+			return callback(error) if error?
+			runner (error1, args...) ->
+				LockManager.releaseLock key, lockValue, (error2) ->
+					error = error1 or error2
+					return callback(error) if error?
+					callback(null, args...)