I have been trying to figure out, what exactly a inbound end point and outbound end point. For me it is bit of an eluding to understand.
what are exactly inbound and outbound endpoints for/do in mule flow? if a flow wants send message which endpoint shoud be used viz when receiving. Or when an application want to invoke a flow which end point it should communicate to?
Inbound endpoints are message sources (http://www.mulesoft.org/documentation/display/current/Message+Sources), which as the name suggests is where messages are created. They can be created based on external events (like an incoming HTTP request or JMS message) or by polling (like files in a directory).
Outbound endpoints and anything else you see in a flow (except exception strategies) are message processors (http://www.mulesoft.org/documentation/display/current/Message+Processors), which means they do something with the message in-flight the flow. Outbound endpoints are message processors that send the current message to "destinations" like a JMS queue, an HTTP server, a file, ...
Disclaimer: This is a simplified view to give you a general idea, its not the beginning or end of what you can do with mule (or other service buses)
Mule is a message processing engine. You can think of it as a giant conveyer belt. You put something on one end, and it goes along the belt and comes out the other end.
The thing that mule deals with are called messages.
The starting point is the "inbound end point" and the exit point is the "outbound end point"; between these pairs of end points you can have other things that will process the message as it travels from the start to the end.
A combination of a start end point + gubbins in the middle to do some work on the message + outbound end point is called a flow. You can chain flows together to create a workflow or process.
These processes are then packaged as an application and uploaded to the mule server. The process only runs when a message that it is listening for arrives. Otherwise the processes are sitting idle. Think of it like a car assembly line. The assembly line that fixes the seats in the car can only start when the chassis is finished; otherwise there is nothing for it to do. Once the seats are fixed, only then can the paint assembly line start, and so on.
Inbound Endpoint: To get the data in mule app from outside.
Outbound Endpoint: To pass the data from the mule app to the outside.
There are two types of connectors available based on operation.
Inbound Endpoint based connector : Inbound endpoint based connectors are the connectors which is placed inside a message
source area of a mule flow which is used to start executing or
triggering off the flow upon receiving the request. (or which is
used to receive the incoming request and pass the request to the
next message processors in a flow for further processing)
Outbound Endpoint or Process based connector: Outbound Endpoint based connectors are placed anywhere within a message processor
area of a flow at beginning or in the middle or at the end.
Regards,
Rajnish
Giving below the structure definition of Mule Message Object has Message Inbound Property Outbound Property Payload Variable Flow Variable Session Variable Attachment Exception Payload
When a connector of a flow (listening on a port) receives the payload its called Inbound endpoint. When in a flow we have a connectore placed in the middle and send a payload its called Oubound endpoint. Here the all the outbound properties sent to the Http Outbound flow become Inbound Properties within that flow.
For detailed explanation see the link below.
https://docs.mulesoft.com/mule-user-guide/v/3.8/mule-message-structure.
Related
we are trying to audit all incoming/outgoing messages, header information in our mule flow.
For same we have tried to use 'wire-tap' which we dint found so useful also its working on mule 3.6.1 but giving error in 3.7.
Any idea/suggestion for auditing?
Ok let me add some more details:
What we are trying to do is- Whatever message comes or flows via flow components we want to copy it in some sub flow (say in queue) without interrupting the main flow so that we can check the message.
you can make it work in several ways
1) Wire tap is one of the choice. You can route your messages asynchronously to sub flow and sub flow will do the auditing work. But I don't know why you didn't found wiretap useful. Can you explain in more.
2) All the messages your receive from the main flow, those you can post to JMS queue. So another flow will read from there and do the auditing work. Use of this multiple projects can use the same piece of code and post JMS queue for auditing.
This can be done in many different ways and you kind of mentioned them in your question such as logger component and interceptor.
All the headers are available as message properties so if you log the entire message they are shown. Simply put an logger component after the inbound endpoint and one before the outbound endpoint and this is easily done.
If you need some log entries transformation you could always put that in a wire tap so you don't interfere with the functionality of your flow.
I understand ESB has in-sequence, out sequence and fault sequence, Is in-sequence same as main sequence ?
Also I would like to know if we define receive sequence in a endpoint will it override default behaviour and response is handled by specified received sequence ? Will response handled by default sequence if received sequence is not specified explicitly ?
Most of the WSO2 ESB examples in internet are based on proxy service, I would like to understand how sequence can be used without proxy service, Can you please introduce me to a such tutorial ?
Triggering Messages
Messages come into the ESB through the following triggers:
A proxy service receives messages that have been sent to a specific endpoint.
A task injects a message into the ESB at a scheduled interval.
A REST API call sends a message to the ESB.
When the ESB receives a message, it sends it either to a proxy service or to the Main sequence for handling. The proxy or sequence is configured with message mediation, which controls how the message will be transformed, filtered, forwarded, etc.
To trigger messages in the ESB, see the following topics:
Creating APIs
Working with Proxy Services
Working with Tasks
Using REST
Source = https://docs.wso2.com/display/ESB481/Triggering+Messages
About the Main and Fault Sequences
A mediation configuration holds two special sequences named main and fault. All messages that are not destined for Proxy Services are sent through the main sequence. By default, the main sequence simply sends a message without mediation, so to add message mediation, you add mediators and/or named sequences in the main sequence.
By default, the fault sequence will log the message, the payload, and any error/exception encountered, and the drop mediator stops further processing. You should configure the fault sequence with the correct error handling instead of simply dropping messages. For more information, see Error Handling.
Source = https://docs.wso2.com/display/ESB481/Mediation+Sequences#MediationSequences-mainSequence
Also I would like to know if we define receive sequence in a endpoint will it override default behaviour and response is handled by specified received sequence ? Will response handled by default sequence if received sequence is not specified explicitly ?
Correct , in a proxy though , and the default behaviour is to send to "out sequence"
I am also a beginner at this , just know what I know through (a lot of) trial and error ;)
Ok so assuming you have a default offset of 0 , you're ESB instance should have 2 default transports/ports :
HTTP = 8280
HTTPS = 8243
So , any message sent to these ports will reach the main sequence , UNLESS , they are service specific endpoints, so for example , for a soap message with endpoint :
http://localhost:8280
this will reach the default main sequence , and the following
https://localhost:8243/services/yourProxyService ,
will got to the in sequence of the yourProxyService.
Also , in [esb_home]/repository/conf/log4j.properties , set/uncomment the following lines :
log4j.logger.httpclient.wire.header=DEBUG
log4j.logger.httpclient.wire.content=DEBUG
log4j.category.org.apache.synapse=DEBUG ,
this should show you much more info in the log and make it easier to know which sequence you are in..
feel free to ask me other stuff , cool
I need to implement a logic on Retry. Inbound endpoint pushes the messages to Rest (Outbound). If the REST is unavailable, I need to retry for 1 time and put it in the queue. But the second upcoming messages should not do any retry, it has to directly put the messages in to queue until the REST service is available.
Once the service is available, I need to pushes all the messages from QUEUE to REST Service (in ordering) via batch job.
Questions:
How do I know the service is unavailable for my second message? If I use until Successful, for every message it do retry and put in queue. Plm is 2nd message shouldn't do retry.
For batch, I thought of using poll, but how to tell to poll, when the service becomes available to begin the batch process. (bcz,Poll is more of with configuring timings to run batch)?
Other ticky confuses me is - Here ordering has to be preserved. once the service is available. Queue messages ( i,e Batch) has to move first to REST Services then with real time. I doubt whether Is it applicable.
It will be very helpful for the quick response to implement the logic.
Using Mule: 3.5.1
I could try something like below: using flow controls
process a message; if exception or bad response code, set a variable/property like serviceAvailable=false.
subsequent message processing will first check the property serviceAvailable to process the messages. if property is false, en-queue the messages to a DB table with status=new/unprocessed
create a flow/scheduler to process the messages from DB sequentially, but it will not check the property serviceAvailable and call the rest service.
If service throws exception it will not store the messages in db again but if processes successfully change the property serviceAvailable=true and de-queue the messages or change the status. Add another property and set it to true if there are more messages in db table like moreDBMsg=true.
New messages should not be processed/consumed until moreDBMsg=false
once moreDBMsg=false and serviceAvailable=true start processing the messages from queue.
For the timeout I would still look at the response code and catch time-outs to determine if the call was successful or requires a retry. Practically you normally do multi threading anyway, so you have multiple calls in parallel anyway. Or simply one call starts before the other ends.
That is just quite normal.
But you can simply retry calls in a queue that time out. And after x amounts of time-outs you "skip" or defer the retry.
But all of this has been done using actual Mule flow components like either:
MEL http://www.mulesoft.org/documentation/display/current/Mule+Expression+Language+Reference
Or flow controls: http://www.mulesoft.org/documentation/display/current/Choice+Flow+Control+Reference
Or for example you reference a Spring Bean and do it in native Java code.
One possibility for the queue would be to persist it in a database. Mule has database connector that has a "poll" feature, see: http://www.mulesoft.org/documentation/display/current/JDBC+Transport+Reference#JDBCTransportReference-PollingTransport
I need to create an "accumulator" service to be used by Mule ESB applications.
This service will hold inbound messages until a certain number are received and then package those messages into a single outbound message.
This is the first time I've needed to write an ESB application that needs to maintain state (the collection of previously received messages) across inbound messages and I'm not quite sure how to get started.
I think what I need is a place to hang a reference to a data structure that holds my lists of inbound messages, but I'm not sure.
What's the best (most productive, most consistent with ESB best-practices) mechanism for managing "application-level" (i.e. cross-message) state data?
Thanks.
For this scenario you need to use the aggregator pattern. Please follow the below link .
http://www.mulesoft.org/documentation-3.2/display/32X/Message+Splitting+and+Aggregation
There is a situation where I need to have a suspend kind of behavior on my Active MQ JMS inbound endpoint when my output endpoint is down. So that I don't process the messages from the queue. Once Then output endpoint is up I want to resume the queue fetching operations. Is this possible in Mule? If yes how ?
You should be able to do something like this:
Connector connector = muleRegistry.lookupConnector(connectorName);
connector.stop();
However, this is not really a straight forward solution if you care about message loss. There will be some time before the connector goes down and the very message at hand, which triggered this "stop" might be lost, if you don't handle those cases with care.
There is another option. Say your other resource is down just for some small amount of time,, you might want to just use JMS transactions and roll back the message to the queue (which it will be when the output endpoint fails) then it will retry the transaction over and over.