Cache Scope in Mule





Cache Scope in Mule




The Cache scope is for storing and reusing frequently called data. You can use a Cache scope to reduce the processing load on the Mule instance and to increase the speed of message processing within a flow. It is particularly effective for these tasks:


1. Processing repeated requests for the same information.

2. Processing requests for information that involve large, non-consumable payloads.

When a message processor in a Mule app sends a message to the Cache scope, the parent flow expects an output. The Cache scope processes the message payload, delivers the output to the parent flow, and saves the output (that is, caches the response). The next time the Cache scope receives the same kind of message payload, the scope can offer a cached response rather than invoking a potentially time-consuming process again.

For instance, you can use a Cache scope to manage customer requests for flight information. Many customers might request the same pricing information about flights from San Francisco to Buenos Aires. Rather than using a lot of processing power to send separate requests to several airline databases with each customer query, you can use a Cache scope to arrange to send a request to the databases fewer times – say, once every ten minutes – and present users with the cached flight pricing information. Where timeliness of data is not critical, Cache scope can save time and processing power.


Note that you can put any number of message processors (such as connectors or components) into a Cache scope and configure the Caching Strategy to store the responses (which contain the payload of the response message) produced by the processing that occurs within the scope.

flow of cache scope :




Here in above example if you get particular data from database it gets stored in object store via a caching strategy.So when we retrieve same data from database multiple times,it gets from object store.


Cache scope configuration :



Select Reference to a strategy and click on + for new configuration.

Give name and click + button and select core:in-memory-store



do configuration for core:in-memory-store as shown below






URL : http://localhost:8085/api/cache
Method : GET

Input :

http://localhost:8085/api/cache?name=himanshu

When you hit for first time it fetch data from database and store it in object store.Second time it will fetch from object store via cache scope.


Output :



XML project code :



<?xml version="1.0" encoding="UTF-8"?>


<mule xmlns:db="http://www.mulesoft.org/schema/mule/db" xmlns:json="http://www.mulesoft.org/schema/mule/json" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:ee="http://www.mulesoft.org/schema/mule/ee/core" 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"
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/db http://www.mulesoft.org/schema/mule/db/current/mule-db.xsd
http://www.mulesoft.org/schema/mule/json http://www.mulesoft.org/schema/mule/json/current/mule-json.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/core http://www.mulesoft.org/schema/mule/ee/core/current/mule-ee.xsd">
    <http:listener-config name="HTTP_Listener_Configuration" host="0.0.0.0" port="8085" doc:name="HTTP Listener Configuration" basePath="/api"/>
    <db:mysql-config name="MySQL_Configuration" host="localhost" port="3306" user="****" password="****" database="demodata" doc:name="MySQL Configuration"/>
    <ee:object-store-caching-strategy name="Caching_Strategy" keyGenerationExpression="#[flowVars.cachevar]" doc:name="Caching Strategy">
        <in-memory-store name="namecache" maxEntries="1" entryTTL="10000" expirationInterval="10000"/>
    </ee:object-store-caching-strategy>
 

    <flow name="test_cacheFlow">
        <http:listener config-ref="HTTP_Listener_Configuration" path="/cache" doc:name="HTTP"/>
        <set-variable variableName="cachevar" value="#[message.inboundProperties.'http.query.params'.name]" doc:name="Variable"/>
        <ee:cache doc:name="Cache" cachingStrategy-ref="Caching_Strategy">
            <logger message="Not getting data from cache" level="INFO" doc:name="Logger"/>
            <db:select config-ref="MySQL_Configuration" doc:name="Database">
                <db:parameterized-query><![CDATA[select * from info where NAME = #[flowVars.cachevar]]]></db:parameterized-query>
            </db:select>
            <json:object-to-json-transformer doc:name="Object to JSON"/>
        </ee:cache>
    </flow>
</mule>