advanced apex development - asynchronous processes
TRANSCRIPT
Advanced Apex – Asynchronous ProcessesMarch 29th 2016
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Forward-Looking Statement
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Speakers
MJ KahnVice President,OpFocus, Inc.
Kartik ViswanadhaDirector, OpFocusSalesforce MVP
@logontokartik
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Salesforce Developers
Salesforce Developers
Salesforce Developers
This webinar is being recorded! The video will be posted to YouTube and thewebinar 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
The WHAT
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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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Concepts
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Multi tenant Fair Share Handling - Delay
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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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The WHY
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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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The HOW
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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 canAccount[] 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);if (coordinates != null) {
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
trigger Account on Account (before insert, before update) {if (Trigger.isBefore && (Trigger.isInsert || Trigger.isUpdate)) {
Account[] lstAccounts = new Account[]{};for (Account acct : Trigger.new) {
if (Trigger.isInsert || (Trigger.isUpdate && GeocodingUtils.addressChanged(acct, Trigger.oldMap.get(acct.Id)))) { 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 addressGeocodingQueueable 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 geocodedglobal 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 AccountsAccount[] lstAccounts = [select Id, BillingStreet, BillingCity, BillingState, BillingPostalCode, BillingCountry from Account where Id in :lstSObjects];
for (Account acct : lstAccounts) {// Geocode the Account and save the resultsGeocodingUtils.LonLat coordinates = GeocodingUtils.geocodeAccount(acct);if (coordinates != null) {
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 updatedSystem.debug('Number of Accounts updated: ' + numberOfAccountsUpdated);
}
} // End of class
Batchble Apex– 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, // flag it to be geocoded laterfor (Account acct : Trigger.new) {
if (Trigger.isInsert || (Trigger.isUpdate && GeocodingUtils.addressChanged(acct, Trigger.oldMap.get(acct.Id)))) { 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 yearGeocodingSchedulable cls = new GeocodingSchedulable();
System.Schedule('Geocode on Jan 1', '0 30 0 1 1 ? *', cls);
• Run every hourGeocodingSchedulable 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 specified times, can monitor
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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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Deploying Your Code
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Deploying Your Code
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Deploying Your Code
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