Please assume the following scenario,
In a process flow there are three humanTask1, humanTask2, humanTask3; All three are assigned to same userA;
Now, assume there are two process instances (p1, p2) live. Each process instance can be in different tasklevel.
That is, for p1, task status are as, humanTask3-inprogress and for p2, humanTask1-inprogress
To display the tasks for this userA in a web page, I want them to be ordered as they appear in workflow design like,
p2-humanTask1
p1-humanTask3
taskService.getTasksOwned() may not return the tasks list in this order.
How do I ensure the tasks are displayed in this sequence?
I am using jBPM 5.3; LocalTaskService;
AFAIK, there is no out-of-the-box solution for this. You will have to decide your own order and then apply it whether by ordering the result of taskService.getTasksOwned() or by creating and executing a customized version of the query that taskService.getTasksOwned() is using.
Hope it helps,
Related
Suppose I have 3 separate user classes. I want to allocate fix number of users for each class. My code is as below.
class User_1(TaskSet):
# I need 3 users to execute the tasks within this user class
class User_2(TaskSet):
# I need only 1 user to execute the tasks within this user class
class User_3(TaskSet):
# I need only 1 user to execute the tasks within this user class
class API_User_Test(HttpUser):
#I already tried weighting the classes as below.
tasks = {Site_User_1: 3, User_2: 1, User_3: 1}
I've already tried weighting the classes as shown in the code above. But it doesn't work. Some times it will allocate more than 1 users for class User_2 or class User_3. Can someone tell me how to fix this issue.
A weight in Locust is just a statistical weight and is not guarantee. The weights determine how many times a task/user are put into a list to be selected from. When a new task/user is spawned, Locust randomly selects a task from the list. Given your weights:
tasks = {Site_User_1: 3, User_2: 1, User_3: 1}
Statistically speaking, spawning 5 users with weights 3/1/1 would get you 3/1/1 but it may not be that precise every time. While less likely, it's possible you could get 4/0/1 or 3/2/0 or 5/0/0.
From the Locust docs:
If the tasks attribute is specified as a list, each time a task is to be performed, it will be randomly chosen from the tasks attribute. If however, tasks is a dict - with callables as keys and ints as values - the task that is to be executed will be chosen at random but with the int as ratio. So with a task that looks like this:
{my_task: 3, another_task: 1}
my_task would be 3 times more likely to be executed than another_task.
Internally the above dict will actually be expanded into a list (and the tasks attribute is updated) that looks like this:
[my_task, my_task, my_task, another_task]
and then Python’s random.choice() is used pick tasks from the list.
If you absolutely have to have full control over exactly what users are running, I'd probably recommend having a single Locust user with a single task that contains your own logic on what to run. Create your own list of functions to call and iterate through it each time a new user is created. Might have to be external to the user as a global or something. But the idea is you manage the logic yourself and not Locust.
Edit:
Using the single user method to control what's running won't work well if you run on multiple workers as the workers don't communicate with each other. You may consider doing some more advanced things like sending messages between master and workers to coordinate, or use an external source like a database or other service the workers talk to to know what they should run.
Following is a use case in a workflow system
Work order enters into a system. Work order will have a target which goes through different workflow states before completing a work order.
Say Work order for a target Vehicle came into a system - workflow for this work oder involves 2 tasks say
a)wash vehicle
b)inspect vehicle
Say wash vehicle workflow task changes vehicle attribute from "not washed" to "washed". And say "inspect vehicle" workflow task changes vehicle attribute "not inspected" to "inspection done"
If user is pulling work order data user will always see latest vehicle data (in this example assuming both workflow tasks are completed user will see value "washed" and "inspection done". However when user pulls ONLY workflow Task Wash Vehicle data -> user will see "washed" -Though second task was done, workflow Task 1 will only see that that it modified. Getting data for Workflow Task 2 will see both "washed" and "inspection done"
This involves milstoning (audit trail) of data; One approach is as shown below image - where when workflow task modifies data it'll update version number, modified_ts and maintain that version number in it's own data row (via a JOIN table as depicted below). Basically this is nothing but maintaining a reference to a history record for workflow task data so when pulling workflow task data it knows which history record to pull back. please ignore parent_id and other notes, noise in a below picture. it's not relevant for this question.
I am thinking event sourcing will also be another alternative design - however don't want to apply event sourcing(or any other similar solution) as a whole sale solution but only for this particular use case (affecting only 3 or so tables where audit trail matters). I am trying to evaluate if CQRS/Event sourcing is a right fit as a partial solution (again only limited to 3-4 tables which need to preserve history/audit trail data) or ES/CQRS will be an overkill? any other thoughts?
P.S. Though this isn't related to Scala - Scala is a platform we are using hence tagging it to see if there are language specific solutions that can help. tagging Akka for finding out if ES/CQRS via Akka persistence is an option or not. Postgresql is a db - And DB triggers is not a solution I am looking for.
In Locust Load test Enviroment tasks are defined and are called randomly.
But if i want a task to be performed just after a specific task. Then how do i do it?
for ex: after every 'X' url call i want 'Y' url to be called based on the response of 'X'.
In my experience, I found that it's better to model Locust tasks as completely independent of each other, and each of them covering a user scenario or behavior (eg. customer logs in, searches for a book and adds it to the cart). This is mostly because that's a closer simulation of the user's behavior.
Have you tried just having the multiple requests on the same task, and just if / else based on your responses? This slide from Carl Byström's talk follows said approach.
You just have to make a sequential gets or posts. When you define your task do something like this:
#task(10)
def my_task(l):
l.client.get('/X')
l.client.get('/Y')
There's an option to create a custom task set inherited from TaskSequence class.
Then you should add seq_task decorators to all task set methods to run its tasks sequentially.
https://docs.locust.io/en/latest/writing-a-locustfile.html#tasksequence-class
The result of SqlWorkflowInstanceStore.WaitForEvents does not tell me what type of workflow is runnable. The constructor of WorkflowApplication takes a workflow definition, and at a minimum, I need to be able to store a workflow ID in the store and query it, so that I can determine which workflow definition to load for the WorkflowApplication.
I also don't want to create a SqlWorkflowInstanceStore for each custom workflow type, since there may be thousands of different workflows.
I thought about trying to use WorkflowServiceHost, but not every workflow has a Receive activity and I don't think it is feasible to have thousands of WorkflowServiceHosts running, each supporting a different workflow type.
Ideally, I just want to query the database for a runnable workflow, determine its workflow definition ID, load the appropriate XAML from a workflow definition table, instantiate WorkflowApplication with the workflow definition, and call LoadRunnableInstance().
I would like to have a way to correlate which workflow is related to a given HasRunnableWorkflowEvent raised by the SqlWorkflowInstanceStore (along with the custom workflow definition ID), or have an alternate way of supporting potentially thousands of different custom workflow types created at runtime. I must also load balance the execution of workflows across multiple application servers.
There's a free product from Microsoft that does pretty much everything you say there, and then some. Oh, and it's excellent too.
Windows Server AppFabric. No, not Azure.
http://www.microsoft.com/windowsserver2008/en/us/app-main.aspx
-Oisin
I have 7 workflow that need to execute; that need to run in certain order ? Is there any scheduling service for this in wf4 or any other approach i can use?
Ocean
If you need to run them sequentially in a certain order, why not just create another workflow and put all 7 of your workflows as activities in a top sequential activity?
If you create an activity that derives fron NativeActivity you can schedule child activities in any order you like. That is the closest thing to a "SchedulerService" I can think of.
However you have to know the activites you want to run at compile time. You can only arrange the order differently using this approach.
If you don't know which activities you want to use at compile time you could use a parent/child technique I showed on my blog WF4 How To Invoke a Child Workflow as XAML