Deacticate User based on last login date - asynchronous

Question

Scenario: Deactivate the user whose login date is less than 42 from today. I have an user whose last login date is 1/22/2020(US Date format)/22/1/2020 5:12 pm. Here I wrote a batch apex for deactivating. My code has executed successfully and my batch status is completed but the user record is not deactivating.
Here is the code:
global class User_Deactivation implements Database.Batchable<SObject>
{
dateTime dt = date.today()-42;
public String query = 'SELECT Name, LastLoginDate, Id From User WHERE IsActive = true AND LastLoginDate=:dt ';
global Database.querylocator start(Database.BatchableContext bc)
{
return Database.getQueryLocator(query);
}
global void execute(Database.BatchableContext bc,List<User> scope)
{
List<User> userList = new List<User>();
for(User s:scope)
{
User u =(user)s;
userList.add(u);
}
if(userList.size() > 0)
{
for(User usr : userList)
{
usr.isActive = false;
}
}
update userList;
}
global void finish(Database.BatchableContext bc)
{
AsyncApexJob a = [SELECT Id, Status, NumberOfErrors, JobItemsProcessed, TotalJobItems, CreatedBy.Email
FROM AsyncApexJob
WHERE Id = :BC.getJobId()];
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
String[] toAddresses = new String[] {a.CreatedBy.Email};
mail.setToAddresses(toAddresses);
mail.setSubject('Apex Job Status: ' + a.Status);
mail.setPlainTextBody('The batch Apex job processed ' + a.TotalJobItems + ' batches with '+ a.NumberOfErrors + ' failures.');
Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
}
}
please help me out on this

Answer 1

Multiple things you can improve here, where do I begin...
Initialisation(?) piece
dateTime dt = date.today()-42;
String query = 'SELECT Name, LastLoginDate, Id From User WHERE IsActive = true AND LastLoginDate=:dt';
Do you need Date or DateTime match? The way you wrote it it'll match only people who logged in exactly at midnight. System.debug(dt); would say 2020-01-23T00:00:00.000Z. It shouldn't be an equals sign, should be "less than" or "less or equal".
Or even better - you can make it bit more clear what you want to do, bit more "semantic" so the poor guy who's going to maintain it can understand it without extra comments. This reads more natural and uses the SOQL date literals, special "constants" to simplify your logic: SELECT Id, LastLoginDate FROM User WHERE isActive = true AND LastLoginDate != LAST_N_DAYS:42
What is this section of code anyway. It's not really static variables, it's not a constructor... I think it'll behave as a constructor. Be very, very careful with constructors for batches. The state of the class at the end of the constructor gets saved (serialised) and restored every time the class is scheduled to run. It's tempting to put some initialisation code into constructor, maybe read some custom settings, precalculate stuff... But then you'll be in for nasty surprise when admin adds new custom setting and the batch doesn't pick it up. In your case it's even worse, I'd suspect it'll serialise the dt and your today() will be frozen in time, not what you expected. To be safe move all initialisation logic to start()
And I'd even say whoever gave you the requirement didn't think it through. When you make new user they get a link they need to click in next 72h. If they didn't do it (maybe it was sent late Friday and they want to login on Monday) - this thing will dutifully kill their access at Friday night without giving them any chance to login. You need some "grace period". Maybe something like WHERE isActive = true AND (LastLoginDate < :x OR (LastLoginDate = null AND CreatedDate < :x))
start()
Queries in strings work and that's how a lot of batch documentation is written but they are poor practice. Where possible use a compiled query, in brackets. You get minimal improvement in execution (precompiled), you get compile-time warnings when you mess up (better than a runtime error which you might not notice if you don't monitor jobs). And most importantly - if somebody wants to delete a field - SF will detect a dependency and stop him/her. Use return Database.getQueryLocator([SELECT ...]); wherever you can.
execute()
Your scope already is a list of users, why do you do extra casts to User? Why do you add them to a helper list? Why 2 loops?
for(User u : scope){
u.isActive = false;
}
update users;
and you're done?
P.S. Why "global" all over the place?