Both are open source ESB. So what are distinct features each of them have and in which scenarios/usecases, each should be used?
Apache camel is basically a Mediation engine which will help you to define
mediation and routing rules for your application,
whereas Activemq is a message broker that allows you to
send messages between producers and consumers using Java Messaging System (JMS)
Apache Camel can use ActiveMQ for forwarding of messages.
Both are altogether different types of systems, with different functionalities, and can not be compared
hope this helps!
Good luck!
Related
EDIT2: My issue here was caused by an insufficient understanding of how transport connectors work in ActiveMQ. TL;DR is that ActiveMQ will implicitly "transform" or "relay" messages between your transport connector configurations defined in activemq.xml.
EDIT: Additional info, the STOMP messages received by the Angular application are used for debugging and demo purposes. Hence, simply converting the OpenWire message to a blob of readable text is sufficient.
I'm creating an Angular application (preferably website, avoiding native applications), which objective is to "tap in" by web sockets on an ActiveMQ server and subscribe to OpenWire messages. How do I let ActiveMQ transform OpenWire messages to STOMP messages and send these to any clients (i.e. my Angular application) connected to the ActiveMQ WebSocket connector?
In addtiion, it would be nice-to-have if I could transform STOMP to OpenWire as well.
It must be Angular
Avoiding the use of native applications on the client-side is preferable although not a deal-breaker.
Adding extra processing stress on the ActiveMQ server must be done with caution.
To the best of my knowledge, it is only possible to let Angular "talk directly" with the ActiveMQ server by STOMP messages send by web socket, if I am to avoid using native applications.
I already have an Angular application capable of STOMP communication by web sockets (e.g. something like https://github.com/stomp-js/ng2-stompjs-angular7).
I am missing information on how to configure the ActiveMQ server to transform OpenWire-->STOMP through its transport connectors.
In my understanding, what I am trying to do should be possible. It is noted by other users but not how. E.g. users hint that what I want is possible in ActiveMQ but not Apollo: ActiveMQ to Apollo transition, Openwire to Stomp protocol configuration.
I expect (preferably) the need to use something like an ActiveMQ transformer (e.g. adding transformer to the connector configuration: AMQP & Openwire - Activemq broker and 2 different consumers) or maybe writing an ActiveMQ plugin (http://activemq.apache.org/developing-plugins.html). On ActiveMQ's website, an existing transformer is mentioned (http://activemq.apache.org/stomp.html Message Transformations section):
Currently, ActiveMQ comes with a transformer that can transform XML/JSON text to Java objects
... but no mention of how to use this and I am unsure if I can benefit from this and if this means that there are no transformers for OpenWire-->STOMP or vice versa.
I expect I might have misunderstood some of the concepts, and a "you're going in a wrong direction, do this instead" can work out as a good answer for me. At the time of writing, I expect I will have to create an ActiveMQ plugin using their Message Transformer interface (http://activemq.apache.org/message-transformation.html) although their sub links are 404. I hope to achieve a more simple solution, e.g. an existing OpenWire-->STOMP transformer:
<transportConnector name="openwire" uri="{some-openwire-uri}?transport.transformer=stomp"/>
ActiveMQ will "transform" any Openwire message into a STOMP message and vice versa as needed based on client connections. I an Openwire based JMS client connects and places a message onto a queue and a STOMP based client comes along and subscribes to that queue the message will be converted into a STOMP message to send to that client.
Without knowing more about what issue you are having it is hard to provide more insight than that though. There are some cases where the transformation from Openwire to STOMP might not yield exactly the right thing for you such as a MapMessage or StreamMessage and definitely an ObjectMessage so some care needs to be taken about cross protocol messaging.
You do of course need to add a transport connector for each of the protocols you want to support, Openwire, STOMP, AMQP etc. The clients need something to connect to, then once they connect the broker manages the message transformations amongst subscriptions on Topics and Queues.
The only answer that I can find seems to say that the datapower appliance only support Websphere MQ, and it doesn't understand ActiveMQ brokers.
And, the documentation for Front Side Handler mentioned Queue managers, which ActiveMQ does not have.
Is there another way in datapower to fetch/poll messages from an activeMQ?
WDP does not support all possible brokers but just a few of them (Tibco, IBM etc). If you configure AMQ to provide a REST interface you can consume messages from it using plain HTTP instead of messaging.
REST/HTTP access to ActiveMQ won't be nearly as good as traditional OpenWire/AMQP connections. It will lack support for transactions and other things, but you can at least read messages.
I do not suggest using an ActiveMQ as messaging backbone for DataPower - go for IBM WebSphere MQ instead as they are nicely integrated. If you need to occasionally pull a message or two from an ActiveMQ broker - go for the above setup.
Is not Apache Kafka another implementation of JMS?
I am using JMS+AMQ in my application, and migrating to Apache Kafka. Do I have to change all JMS codes?
No, Kafka is different from JMS systems such as ActiveMQ.
see ActiveMQ vs Apollo vs Kafka
Kafka has less features than ActiveMQ, as the stress has been put on performances. So before migrating, check that the features you use in AMQ are in Kafka.
However, there is an open suggestion for a bridge between JMS and Kafka, to allow exactly what you need. Maybe the provided links can help you
https://issues.apache.org/jira/browse/KAFKA-1995
Actually, the two are not the same. And with a little more time seeing the two co-exist - and listening to problems and happy points from those deploying each in the field - there is a little more to say about each one.
Firstly, JMS supports both point-to-point messaging (where messages are sent to single consumers; the consumers themselves maintain their message queues) and the publish-and-subscribe (pub/sub) model (where messages are written to a single topic, and consumers, independently, decide which messages to consume).
In a point-to-point messaging architecture, message producers and consumers know each other, where as in a pub/sub model they do not. Apache Kafka focuses on a pub/sub model, maintaining a separate log/topic from which consumers read from offsets. Kafka is also built for the cloud, with high-throughput a core consideration.
Many in our community and at meetups throw their hands up in frustration at MOMs (message-oriented middlewares) like JMS and switch to Kafka, for, what boils down to one reason: scalability. They argue that Kafka is better suited for scale than other MOMs because Kafka maintains a partitioned topic log. In so doing, Kafka can split up message flow to groups of consumers by partition and batch transmit the messages.
This concept also allows Kafka to have more granular control over ACLs (access control) to Kafka Consumers, although there are some issues there, which Apache Pulsar is addressing.
Finally, on Kafka, since the client/consumer decides which messages to consume (by offset in the topic), this removes some of the producer-side complexity of routing rules built into MOMs like JMS.
There's more differences than that, but this is a distillation of some of the ones that keep coming up! Hope this helps.
No, Kafka uses its own non-standard protocol and clients.
However, there's a 3rd-party JMS Client for Kafka from Confluent.
RabbitMQ supports multiple protocols, AMQP, MQTT, STOMP, ....
When using PHP for example, it's easier to publish using the STOMP library since the PHP AMQP libraries requires compiled C code and is somewhat of a mission to setup if you don't have to.
On the JAVA side, apache camel with AMQP on spring is pretty straight forward.
Is it possible to setup a queue, publish to it via STOMP and then consume via AMQP and then again publish via AMQP and consume via STOMP if the message broker is RabbitMQ?
Yes, this should work, given that you have installed RabbitMQ's STOMP plugin on your RabbitMQ node(s).
The protocol only defines the communication between client and server and has no impact on a message itself.
You should note that using protocols other than AMQP will most likely come along with limitations and/or worse performance.
There also exist native PHP libraries for RabbitMQ that don't require compiling C code. Unfortunately, I cannot tell you which one is the best, because I am a Java guy ;-).
I'm currently in the middle of developing a webapplication which needs a websocket connection to receive notifications of events from the server.
The clients are separated in groups and all the clients in a group must receive the same event notifications.
I thought that ActiveMQ could probably support this model, using different queues for each group of clients. It would also be relatively easy to push events to ActiveMQ using stomp, and then use stomp-over-websockets for the clients.
The problem I see is that messages should not be consumed by only one client, but distributed to all the clients connected to the queue.
Also the queue should not be stored. If a client is not connected when the event is generated, then it will never receive it.
I don't know ActiveMQ that much, so I'm not sure if this is possible or if there is another easy solution that could be used instead of writing my own message server.
Thanks
ActiveMQ 5.4.1 supports WebSockets natively (just like Stomp, JMS, etc.).
There is the concept of queues (you mentioned these), but also of topics.
In a queue, a single message will be received by exactly one consumer, in a topic
it goes to all the subscribers. See: http://activemq.apache.org/how-does-a-queue-compare-to-a-topic.html
There are some Stomp-WebSocket JS libraries floating around. Kaazing has a bundle that includes ActiveMQ and supports JMS API/Stomp protocol over WebSockets with support for older browsers, different client technologies, and Cross-Site security.
Look at Pusher, otherwise you'll need something that supports topic based pub/sub. You could look at Redis or RabbitMQ