Advanced Apex Development - Asynchronous Processes

Advanced Apex – Asynchronous Processes
March 29th
2016

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Speakers
MJ Kahn
Vice President,
OpFocus, Inc.
Kartik Viswanadha
Director, OpFocus
Salesforce MVP
@logontokartik

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Go Social!
@salesforcedevs / #forcewebinar
Salesforce Developers
This webinar is being recorded! The video will be posted to YouTube and the
webinar recap page (same URL as registration).

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Agenda
• What is Asynchronous Process?
• Why we need it?
• Types of Asynchronous Processes in Salesforce
• Usage and Examples
• Comparison of various Asynchronous Processes
• Appendix
• Recap

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Pre-requisites
• Good understanding of Apex Programming on Salesforce
• Passion to learn the platform

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Asynchronous Process - Definition
• In computer
programs,
asynchronous
operation means
that a process
operates
independently of
other processes

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Asynchronous vs Synchronous
Synchronous
• Quick and
Immediate Actions
• Transactions are
immediate and
serial
• Normal governor
limits
Asynchronous
• Actions that will not
block the
transaction pr
process
• Duration is not a
Priority
• Higher governor
limits

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Asynchronous Process – Force.com
• Ensure fairness of
processing
• Ensure
transactional
capabilities

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Queue Based Framework

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Multi tenant Fair Share Handling - Delay

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Multi tenant Fair Share Handling – Extended Delay
All the rquests from Org 1 are moved back with an
Extended Delay

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Benefits
• User Efficiency
• Resource Efficiency
• Scalability

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Why Asynchronous Processes in Salesforce
• Avoid Governor Limits
• Mixed DML Operations
• Long Running User Operations

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Use Cases
• Send Data to an External System on a Insert or Update
• Complex Calculations or Analysis based on Data in Salesforce
• Report Runs
• Callouts to External Systems

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Use Case – Large Data Processing

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Use Case – Logic on Millions of Rows
• Supports complex logic on very
large datasets
• Scalable, robust, asynchronous
execution platform
• Scheduled or programmatically
executed
• Eliminate ‘data processing’
integrations
• Data cleansing, augmentation
• Automated batch process

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Types of Asynchronous Processes in Apex
• @future
• Queueable
• Batch Apex
• Schedulable
• Continuation

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Scenario
• Goal: Populate Account’s Billing Longitude/Latitude based on
Billing Address
• Assume we have a method that calls out to a web service and
returns the lon/lat for a given Account, in the Geocoding Utils class
public static LonLat geocodeAccount(Account acct) { … }
LonLat is a class with 2 Double properties.
• Solution: Write a trigger that calls this method.
• Problem: You can’t call out to a web service from a trigger.

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@future
• A public static method, decorated with @future
• Arguments:
• Primitives (Integer, String, etc.)
• Collections of primitives (List, Map, Set)
• NOT Sobjects or Apex objects
• You can use JSON.serialize() and pass in a String
• Returns void

@future
public class GeocodingUtils {
@future (callout=true)
public static void geocodeAccountFuture(Id accountId) {
Account acct =
[select Id, BillingStreet, BillingCity, BillingState, BillingPostalCode, BillingCountry
from Account
where Id = :accountId];
LonLat coordinates = geocodeAccount(acct);
if (coordinates != null) {
acct.BillingLongitude = coordinates.lon;
acct.BillingLatitude = coordinates.lat;
update acct;
}
}
}

@future – Account trigger
trigger Account on Account (before insert, before update) {
if (Trigger.isBefore && (Trigger.isInsert || Trigger.isUpdate)) {
// For each new Account or each existing Account whose Address has changed, geocode it
for (Account acct : Trigger.new) {
if (Trigger.isInsert ||
(Trigger.isUpdate && GeocodingUtils.addressChanged(acct, Trigger.oldMap.get(acct.Id)))) {
// Geocode the Account's address
GeocodingUtils.geocodeAccountFuture(acct.Id);
}
}
}
}

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Queueable Class
• A public class that implements the Queueable interface
• Includes an execute method that accepts only a QueueableContext
parameter
• The execute method can access instance properties for the
class
• Returns void
• Launch by calling System.enqueueJob(cls) with an instance of the
class.
• Returns an AsyncApexJob Id

Queueable Apex
public class GeocodingQueueable implements Queueable, Database.AllowsCallouts {
public Account[] lstAccounts = new Account[]{};
public void execute(QueueableContext ctx) {
// Process as many Accounts as we can
Account[] lstProcessed = new Account[]{};
Integer numProcessed;
for (numProcessed=0;
numProcessed < Limits.getLimitCallouts() && numProcessed<lstAccounts.size();
numProcessed++) {
Account acctGeo = lstAccounts[numProcessed];
GeocodingUtils.LonLat coordinates = GeocodingUtils.geocodeAccount(acctGeo);
acctGeo.BillingLongitude = coordinates.lon;
acctGeo.BillingLatitude = coordinates.lat;
lstProcessed.add(acctGeo);
}
}

Queueable Apex
…
update lstProcessed;
// Remove the ones we just processed from the list.
for (Integer i=0; i<numProcessed; i++) {
lstAccounts.remove(0);
}
// If there are any remaining Accounts, chain a new Async job to process them.
// NOTE: As of Spring 16, a chained Queueable job cannot do a callout, so the next
// run of this execute() method will fail!
if (!lstAccounts.isEmpty()) {
Id jobID = System.enqueueJob(this);
}
}
}

Queueable Apex– Account trigger
Account[] lstAccounts = new Account[]{};
Account acctGeo = new Account(Id=acct.Id);
acctGeo.BillingStreet = acct.BillingStreet;
acctGeo.BillingCity = acct.BillingCity;
acctGeo.BillingState = acct.BillingState;
acctGeo.BillingPostalCode = acct.BillingPostalCode;
acctGeo.BillingCountry = acct.BillingCountry;
lstAccounts.add(acctGeo);
}
}
if (!lstAccounts.isEmpty()) {
// Geocode the Account's address
GeocodingQueueable cls = new GeocodingQueueable();
cls.lstAccounts = lstAccounts;
Id jobID = System.enqueueJob(cls);
}
}
}

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Batchable Class
• A global class that implements the Database.Batchable interface
• Includes:
• Start method – identifies the scope (list of data to be processed)
• Execute method – processes a subset of the scoped records
• Finish method – does any post-job wrap-up
• Additional interfaces:
• Database.Stateful
• Database.AllowCallouts

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Batchable Class
• Launch by callling Database.executeBatch(cls) with an instance of
the class and an optional scope size
• Default scope size is 200
• Returns an AsyncApexJobId

Batch Apex
global class GeocodingBatch implements Database.Batchable<SObject>,
Database.AllowsCallouts, Database.Stateful {
global Integer numberOfAccountsUpdated = 0;
// Start method gets all Accounts that need to be geocoded
global Database.QueryLocator start(Database.BatchableContext bc) {
String query = 'select id from Account where Need_to_Geocode__c = true';
return Database.getQueryLocator(query);
}

Batch Apex
global void execute(Database.BatchableContext bc, List<SObject> lstSObjects) {
// Get the Accounts
Account[] lstAccounts =
[select Id, BillingStreet, BillingCity, BillingState, BillingPostalCode, BillingCountry
from Account where Id in :lstSObjects];
for (Account acct : lstAccounts) {
// Geocode the Account and save the results
GeocodingUtils.LonLat coordinates = GeocodingUtils.geocodeAccount(acct);
acct.BillingLongitude = coordinates.lon;
acct.BillingLatitude = coordinates.lat;
}
acct.Need_to_Geocode__c = false;
}
update lstAccounts;
numberOfAccountsUpdated += lstAccounts.size();
}

Batch Apex
global void finish(Database.BatchableContext bc) {
// Send an email to let someone know how many Accounts we updated
System.debug('Number of Accounts updated: ' + numberOfAccountsUpdated);
}
} // End of class

Batchble Apex– Account trigger
// For each new Account or each existing Account whose Address has changed,
// flag it to be geocoded later
acct.Need_to_Geocode__c = true;
}
}
}
}

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Schedulable Class
• A global class that implements the Schedulable interface
• Includes an execute method

Schedulable Apex
global class GeocodingSchedulable {
global void execute(SchedulableContext ctx) {
GeocodingBatch cls = new GeocodingBatch();
Integer batchSize = (Limits.getLimitCallouts() < 200) ? Limits.getLimitCallouts() : 200;
Id jobId = Database.executeBatch(cls, batchSize);
}
}

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Schedulable Class
• Schedule by calling
System.Schedule(‘job name’, cron expression, cls)
• Job Name is found in AsyncApexJob object
• Cron expression can be complex
• Returns an AsyncApexJob Id

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Schedulable Class
• Cron expression string
seconds minutes hours day_of_month month day_of_week optional_year
• Run at 30 minutes past midnight on Jan 1 every year
GeocodingSchedulable cls = new GeocodingSchedulable();
System.Schedule('Geocode on Jan 1', '0 30 0 1 1 ? *', cls);
• Run every hour
GeocodingSchedulable cls = new GeocodingSchedulable();
System.Schedule('Geocode on Jan 1', '0 0 * * * ? *', cls);
• Check the Apex Language Reference for details

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Summary of Techniques
• @future – static method, simple arguments, no monitoring, no
chaining
• Queueable – class with instance variables, can monitor, can chain
(within limits)
• Batch Apex – class with instance variables, great for large numbers
of records, can monitor
• Schedulable – class with instance variables, runs one or at

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Monitoring Async Apex
• For Queueable and Batchable
• When you launch the job, you get an AsyncApexJob Id
• Setup | Monitoring | Apex Jobs
• See doc for description of Status values
• For Schedulable
• When you schedule the job, you get a CronTrigger Id
• When it runs, it’s added to AsyncApexJobs
• Setup | Monitoring | Scheduled Jobs
• Add a list view filter for Type = Scheduled Apex

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Testing Async Apex
• Before launching the job, do Test.startTest()
• After launching the job, do Test.stopTest()
• One instance of the job will run before Test.stopTest() returns

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Recap
• Asynchronous Processes
• Salesforce Async Model & Framework
• Advantages of using Async processes
• Use Cases
• Types of Async Processes
• Comparison & Monitoring

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Resources
• https://developer.salesforce.
com/page/Loading_Large_Data_Sets_with_the_Force.
com_Bulk_API
• https://developer.salesforce.
com/page/Asynchronous_Processing_in_Force_com
• https://developer.salesforce.com/blogs/engineering/2014/05/flex-
batch-apex-muscles-flexqueue.html

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Advanced Apex Development - Asynchronous Processes

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