I'm using MSMQ on Server 2012 with the System.Messaging class, not WCF. When my message is sent to my Private queue I set the TimeToBeReceived property of the message to 1 minute. Should this time expire I need this message to be removed from this queue and placed in a secondary queue. To accomplish this I am setting UseDeadLetterQueue = true which causes the message to be moved to the system DLQ. The problem is of course that this message can get mixed in with messages from other queues.
I have two questions:
Not using WCF, is there a way to specify a custom DLQ?
Is there another way to handle this time expiry and sending the message to another queue that does not involve the DLQ?
Related
I'm wondering if its possible to write a Powershell script to move a message from one MSMQ queue to another?
I have a few failed messages (i.e. messages that did not complete because they involved, say, a call to a server that was down, for example) in an error queue that I would like to retry by moving them back into their original processing queue. I am using NServiceBus v6 handlers to listen for messages that enter the original processing queue that will resend the message if they are put back into that queue.
Has anyone done this before using Powershell?
In particular, I would like to do the following in Powershell:
Find a message based on a specific identifier (string) within the message body
Move this message to a specific queue
I know Powershell has commands such as Move-MsmqMessage. I have been unable to find an example online that I can re-use for this function.
Any help much appreciated.
If you have messages in the error queue from NServiceBus, you can use this tool to return them to the original queue they were in.
https://github.com/ParticularLabs/MsmqReturnToSourceQueue
It checks the headers what the original queue was and sends them there again. The idea is that any endpoint can send messages to the same error queue. They can then either be digested by ServiceControl or any other tool. If you leave them in the error queue, this ReturnToSourceQueue can send them back to the original queue.
I have a transactional private message queue (among other message queues on which I have not seen this problem) on a Windows Server 2008 R2 server.
This particular queue has a recurring problem happening every few weeks where the console shows a nonzero count of messages in the queue, but it does not have any messages in the queue itself or any subqueue. Queue Explorer shows the same thing. Performance counters indicate there are messages like the count in the built-in msmq console and queue explorer.
I cannot find any messages. I understand that I could see a situation like this for outgoing queues with dead letter tracking such that it may have been delivered to a remote machine but not yet processed. This is not an outgoing queue, though. Messages are sourced from remote machines and have landed here on this machine.
Also, I am certain that the count I'm seeing are not journal messages or subqueues.
Does this make any sense? Is there a logical explanation for this and under some circumstance this is expected? If so, what is it?
EDIT: Removed info about purging queue removing the count - that was incorrect. Purging actually does nothing and leaves me in the same state as before with a count reflected, but no messages showing.
As you noted, you can see a message count on an outgoing queue if source journaling is in use. The invisible messages are there in case they need to be moved to the DLQ.I would expect your problem to be similar - there should be a visible message in the outgoing queue and an invisible message in the destination queue because delivery hasn't completed. I assume a handshaking or storage acknowledgement has been lost along the way. Or maybe the message has been processed and removed from the queue but MSMQ couldn't update the sender of the fact. Check the outgoing queues on the remote machines sending TO this queue.
Is there some standard configuration setting, service, or tool that accepts messages from one queue and moves them on to another one? Automatically handling the dead message problem, and providing some of retry capability? I was thinking this is what "MSMQ Message Routing" does but can't seem to find documentation on it (except for on Windows Mobile 6, and I don't know if that's relevant).
Context:
I understand that when using MSMQ you should always write to a local queue so that failure is unlikely, and then X should move that message to a remote queue. Is my understanding wrong? Is this where messaging infrastructure like Biztalk comes in? Is it unnecessary to write to a local queue first to absolutely ensure success? Am I supposed to build X myself?
As Hugh points out, you need only one MSMQ Queue to Send messages in one direction from a source to a destination. Source and destination can be on the same server, same network or across the internet, however, both source and destination must have the MSMQ service running.
If you need to do 'message' routing (e.g. a switch which processes messages from several source or destination queues, or routing a message to one or more subscribers based on the type of message etc) you would need more than just MSMQ queue.
Although you certainly can use BizTalk to do message routing, this would be expensive / overkill if you didn't need to use other features of BizTalk. Would recommend you look at open source, or building something custom yourself.
But by "Routing" you might be referring to the queue redirection capability when using HTTP as the transport e.g. over the internet (e.g. here and here).
Re : Failed delivery and retry
I think you have most of the concepts - generally the message DELIVERY retry functionality should be implicit in MSMQ. If MSMQ cannot deliver the message before the defined expiry, then it will be returned on the Dead Letter Queue, and the source can then process messages from the DLQ and then 'compensate' for them (e.g. reverse the actions of the 'send', indicate failure to the user, etc).
However 'processing' type Retries in the destination will need to be performed by the destination application / listener (e.g. if the destination system is down, deadlocks, etc)
Common ways to do this include:
Using 2 Phase commit - under a distributed unit of work, pull the message off MSMQ and process it (e.g. insert data into a database, change the status of some records etc), and if any failure is encountered, then leave the message back onto the queue and the DB changes will be rolled back.
Application level retries - i.e. on the destination system, in the event of 'retryable' type errors (timeout due to load, deadlocks etc) then to sleep for a few seconds and then retry the same transaction.
However, in most cases, indefinite processing retries are not desirable and you would ultimately need to admit defeat and implement a mechanism to log the message and the error and remove it from the queue.
But I wouldn't 'retry' business failures (e.g. Business Rules, Validation etc) and the behaviour should be defined in your requirements of how to handle these (e.g. account is overdrawn, message is not in a correct format or not valid, etc), e.g. by returning a "NACK" type message back to the source.
HTH
MSMQ sends messages from one queue to another queue.
Let's say you have a queue on a remote machine. You want to send a message to that queue.
So you create a sender. A sender is an application that can use the MSMQ transport to send a message. This can be a .Net queue client (System.Messaging), a WCF service consumer (either over netMsmqBinding or msmqIntegrationBinding, BizTalk using the MSMQ adapter, etc etc.
When you send the message, what actually happens is:
The MSMQ queue manager on the sender machine writes the message to a temporary local queue.
The MSMQ queue manager on the sender machine connects to the MSMQ manager on the receiving machine and transmits the message.
The MSMQ queue manager on the receivers machine puts the message onto the destination queue.
In certain situations MSMQ will encounter messages which for some reason or another cannot be received on the destination queue. In these situations, if you have indicated that a message will use the dead-letter queue then MSMQ will make sure that the message is forwarded to the dead-letter queue.
What all functionality are there in queue which can't be achieved by topic??
The main requirement that I run into is that consumers cannot compete for a single message on a topic. For example, I have a client who publishes call center events. Several systems subscribe to these events. One of these systems is the actual call routing application which has multiple instances running. If each instance subscribes then the call is routed to all of them. However, if the message is dropped onto a queue and all the instances consume off the same queue then only one will receive the message and the call goes to that operator. If the publishing application converts from topics to a queue, the call center works but all the other subscriber apps don't get the message.
The solution (as implemented in WebSphere MQ) was to create an administrative subscription on the topic and deliver the messages to a queue that all application instances consume from. So the producer apps are still publishers, all the dynamic subscribers still get copies of the message and the call center app instances compete for a single instance of each published message.
Also, you can't use browse semantics on a topic whereas you can on a queue. With topics you can specify selectors to filter the messages that are returned but that's about it. With queues you can browse, reset the browse pointer and then browse some more.
If you put a message on a queue and nothing is there to receive it, the message remains queued up. If you put a message to a topic and there are no active subscribers or durable subscriptions, the message is discarded. Therefore messages in a queue are naturally durable whereas messages on a topic may or may not be.
From a pure JMS perspective, queue and topic are both instances of destination and are interchangeable if you don't try to browse. An application may not know whether the destination it opens is a queue or a topic unless it uses instanceOf() at run-time to find out.
I need to work with MSMQ (Microsoft Message Queuing). What is it, what is it for, how does it work? How is it different from web services?
With all due respect to #Juan's answer, both are ways of exchanging data between two disconnected processes, i.e. interprocess communication channels (IPC). Message queues are asynchronous, while webservices are synchronous. They use different protocols and back-end services to do this so they are completely different in implementation, but similar in purpose.
You would want to use message queues when there is a possibility that the other communicating process may not be available, yet you still want to have the message sent at the time of the client's choosing. Delivery will occur the when process on the other end wakes up and receives notification of the message's arrival.
As its name states, it's just a queue manager.
You can Send objects (serialized) to the queue where they will stay until you Receive them.
It's normally used to send messages or objects between applications in a decoupled way
It has nothing to do with webservices, they are two different things
Info on MSMQ:
https://msdn.microsoft.com/en-us/library/ms711472(v=vs.85).aspx
Info on WebServices:
http://msdn.microsoft.com/en-us/library/ms972326.aspx
Transactional Queue Management 101
A transactional queue is a middleware system that asynchronously routes messages of one sort of another between hosts that may or may not be connected at any given time. This means that it must also be capable of persisting the message somewhere. Examples of such systems are MSMQ and IBM MQ
A Transactional Queue can also participate in a distributed transaction, and a rollback can trigger the disposal of messages. This means that a message is guaranteed to be delivered with at-most-once semantics or guaranteed delivery if not rolled back. The message won't be delivered if:
Host A posts the message but Host B
is not connected
Something (possibly but not
necessarily initiated from Host A)
rolls back the transaction
B connects after the transaction is
rolled back
In this case B will never be aware the message even existed unless informed through some other medium. If the transaction was rolled back, this probably doesn't matter. If B connects and collects the message before the transaction is rolled back, the rollback will also reverse the effects of the message on B.
Note that A can post the message to the queue with the guarantee of at-most-once delivery. If the transaction is committed Host A can assume that the message has been delivered by the reliable transport medium. If the transaction is rolled back, Host A can assume that any effects of the message have been reversed.
Web Services
A web service is remote procedure call or other service (e.g. RESTFul API's) published by a (typically) HTTP Server. It is a synchronous request/response protocol and has no guarantee of delivery built into the protocol. It is up to the client to validate that the service has been correctly run. Typically this will be through a reply to the request or timeout of the call.
In the latter case, web services do not guarantee at-most-once semantics. The server can complete the service and fail to deliver a response (possibly through something outside the server going wrong). The application must be able to deal with this situation.
IIRC, RESTFul services should be idempotent (the same state is achieved after any number of invocations of the same service), which is a strategy for dealing with this lack of guaranteed notification of success/failure in web service architectures. The idea is that conceptually one writes state rather than invoking a service, so one can write any number of times. This means that a lack of feedback about success can be tolerated by the application as it can re-try the posting until it gets a 'success' message from the server.
Note that you can use Windows Communication Foundation (WCF) as an abstraction layer above MSMQ. This gives you the feel of working with a service - with only one-way operations.
For more information, see:
http://msdn.microsoft.com/en-us/library/ms789048.aspx
Actually there is no relation between MSMQ and WebService.
Using MSMQ for interprocess communication (you can use also sockets, windows messaging, mapped memory).
it is a windows service that responsible for keeping messages till someone dequeue them.
you can say it is more reliable than sockets as messages are stored on a harddisk but it is slower than other IPC techniques.
You can use MSMQ in dotnet with small lines of code, Just Declare your MessageQueue object and call Receive and Send methods.
The Message itself can be normal string or binary data.
As everyone has explained MSMQ is used as a queue for messages. Messages can be wrapper for actual data, object and anything that you can serialize and send across the wire. MSMQ has it's own limitations. MSMQ 1.0 and MSMQ 2.0 had a 4MB message limit. This restriction was lifted off with MSMQ 3.0. Message oriented Middleware (MOM) is a concept that heavily depends on Messaging. Enterprise Service Bus foundation is built on Messaging. All these new technologies, depend on Messaging for asynchronous data delivery with reliability.
MSMQ stands for Microsoft Messaging Queue.
It is simply a queue that stores messages formatted so that it can pass to DB (may on same machine or on Server). There are different types of queues over there which categorizes the messages among themselves.
If there is some problem/error inside message or invalid message is passed, it automatically goes to Dead queue which denotes that it is not to be processed further. But before passing a message to dead queue it will retry until a max count and till it is not processed. Then it will be sent to the Dead queue.
It is generally used for sending log message from client machine to server or DB so that if there is any issue happens on client machine then developer or support team can go through log to solve problem.
MSMQ is also a service provided by Microsoft to Get records of Log files.
You get Better Idea from this blog http://msdn.microsoft.com/en-us/library/ms711472(v=vs.85).aspx.