This document discusses how to dynamically stop and start Mule processes using Groovy scripts and choice exception handling. It provides steps to identify scenarios to suspend a process, catch errors using choice exception strategies, write Groovy scripts to stop or start processes by checking conditions, and call those scripts from the catch exception strategy or message sources like JMS to control process flows at runtime without redeployment.

2. Sample Demo process
Choice catch exception strategy
Stop Mule process with mule component diagram
Groovy script to stop the process
Start Mule process with mule component diagram
Groovy script to start the process

3.  Sometime when you are developing your
application it becomes important to stop your
particular process dynamically when some specific
error occurred for a long time of period.
 You can start that particular process without any
redeployment.
 For example If your database is down or your
incase your target system is down and you are
hitting continuously your target system.
 We can achieve this in mule via using groovy
script or customizing our code.

4. 1. Identify in which scenario you want to suspend
your process.
2. Use choice exception handling to catch those
errors.
3. Mention the condition in MEL expression to
catch particular scenario.
4. Create a sub process and write the groovy script
to stop the process.
5. Call the sub process from catch exception
strategy once the condition is match.

5. 1. Create the flow to start your process.
2. your message source should be JMS, Anypoint
MQ and SQS etc.
3. Use the groovy script to start the process.

6. 1. Create the flow to start your process.
2. In this example message source is http and your
target is database, in this case if there is any error,
choice exception strategy catch the error, it will 1st
check the error condition if error related to
database connection then this will call sup process
stopflow.

7. Choice exception strategy is used to handle
different type of exception handling on based of
condition. You can specify number of condition
based of your requirement and can handle the error
in different way based on the condition.

8. demoStop sub process will check the condition
flag if flag is true it will stop the specified flow
otherwise simply print the logger and will come at
the end of the flow.

9. This script will first check the flow is started or not and this
will check the flag value will is configured in property file, if
both condition will true in this case it stop the flow.

10. Once your target is up or running you then you can
start your process, to do this you can send message
to your JMS queue this will check the condition and
then will start the flow.

11. This is the groovy script which will start your
process. It first check the condition that the process
is running or not, if it is in stopped condition this
script will start your starter process.

12. Mule doesn’t provide any component that directly stop
and start/restart any process or flow at run time. This
presentation will help you to do this via customizing your
code.