The document discusses the until-successful component in Mule, which processes messages through its processors until the process succeeds. It retries processing asynchronously by default up to a configured maximum number of retries. An example flow is provided that uses until-successful to retry a database query up to 5 times if it initially fails due to a missing table.

1. Until Successful Component In
Mule Demo

2. Abstract
• The main motto of this PPT is how to use Until
Successful component in our applications.

3. Introduction
• The until-successful scope processes
messages through the processors within it
until the process succeeds. By default, until-
successful’s processing occurs asynchronously
from the main flow. After passing a message
into the until-successful scope, the main flow
immediately regains control of the thread.
However, you can configure until-successful to
run synchronously relative to the main flow.

4. Example

5. • .mflow• <?xml version="1.0" encoding="UTF-8"?>
• <mule xmlns:vm="http://www.mulesoft.org/schema/mule/vm" xmlns:jdbc-ee="http://www.mulesoft.org/schema/mule/ee/jdbc"
xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation"
xmlns:spring="http://www.springframework.org/schema/beans" version="EE-3.4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd
• http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd
• http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd
• http://www.mulesoft.org/schema/mule/ee/jdbc http://www.mulesoft.org/schema/mule/ee/jdbc/current/mule-jdbc-ee.xsd
• http://www.mulesoft.org/schema/mule/vm http://www.mulesoft.org/schema/mule/vm/current/mule-vm.xsd">
• <jdbc-ee:mssql-data-source name="MS_SQL_Data_Source" user=“****" password=“****" url="jdbc:sqlserver://localhost;databaseName=test1" transactionIsolation="UNSPECIFIED"
doc:name="MS SQL Data Source"/>
• <jdbc-ee:connector name="Database" dataSource-ref="MS_SQL_Data_Source" validateConnections="true" queryTimeout="-1" pollingFrequency="0" doc:name="Database"/>
• <spring:beans>
• <spring:bean id="Bean" name="Bean" class="org.mule.util.store.SimpleMemoryObjectStore"/>
• </spring:beans>
• <flow name="Database_ComponentFlow2" doc:name="Database_ComponentFlow2">
• <http:inbound-endpoint exchange-pattern="request-response" host="localhost" port="8087" path="UntilSuccessful" doc:name="HTTP"/>
• <logger message="--main flow--" level="INFO" doc:name="Logger"/>
• <expression-component doc:name="Expression"><![CDATA[
• sessionVars['DB_STATUS']='INITIAL';
• ]]></expression-component>
• <until-successful objectStore-ref="Bean" maxRetries="5" secondsBetweenRetries="5" doc:name="Until Successful" failureExpression="#[sessionVars['DB_STATUS']!='SUCCESS']">
• <vm:outbound-endpoint exchange-pattern="request-response" path="db" doc:name="VM"/>
• </until-successful>
• </flow>
• <flow name="Database_ComponentFlow3" doc:name="Database_ComponentFlow3">
• <vm:inbound-endpoint exchange-pattern="request-response" path="db" doc:name="VM"/>
• <jdbc-ee:outbound-endpoint exchange-pattern="request-response" queryKey="select" queryTimeout="-1" connector-ref="Database" doc:name="Database">
• <jdbc-ee:query key="select" value="select * from mytable1"/>
• </jdbc-ee:outbound-endpoint>
• <expression-component doc:name="Expression"><![CDATA[
• sessionVars['DB_STATUS']='SUCCESS';
• ]]></expression-component>
• <logger message="--success" level="INFO" doc:name="Logger"/>
• </flow>
• </mule>

6. • Output:

7. • Flow of execution:
1. URL to trigger the service from browser
http://localhost:8087/UntilSuccessful
2. Database component connects to the specific
database, executes the select query but there is
no table specified in DB, hence the until
successful component retries for 5 times and
exit the flow.

8. References
• https://docs.mulesoft.com/mule-user-
guide/v/3.5/until-successful-scope