Is there any way to pause/resume a running workflow created using chains from celery 3.0?
Basically, we have two different types of tasks in our system: interactive and non-interactive ones. The non-interactive ones we have all the parameters for, but the interactive ones need user input. Note that for the interactive tasks, we can only ask for user input once all the previous taks in the chain have been completed, as their results will affect the interactive tasks (i.e. we cannot ask for user input before creating the actual chain).
Any suggestion on how to approach this? Really at a loss here..
Current ideas:
Create two subclasses of Task (from celery import Task). Add an extra instance (class member) variable to the Interactive task subclass that is set to false by default and represents that some user input is still needed. Somehow have access to the instance of the Task, and set it to true from outside the celery worker (Though I have looked this up quite a bit and it doesn't seem possible to have access to Task objects directly from another module)
Partition the chain into multiple chains delimited by Interactive jobs. Have some sort of mechanism outside the celery worker detect once a chain has reached it's end and trigger the interactive task's interactive client side component. Once the user has entered all this data, get the data, and start the new chain where the interactive task is at the head of the new chain.
We have implemented something like your second idea in our project & it works fine. Here is the gist of the implementation.
Add new field status to your model & override save method.
models.py:
class My_Model(models.Model):
# some fields
status = models.IntegerField(default=0)
def save(self, *args, **kwargs):
super(My_Model, self).save(*args, **kwargs)
from .functions import custom_func
custom_func(self.status)
tasks.py
#celery.task()
def non_interactive_task():
#do something.
#celery.task()
def interactive_task():
#do something.
functions.py
def custom_func(status):
#Change status after non interactive task is completed.
#Based on status, start interactive task.
Pass status variable to template which is useful for displaying UI element for user to enter information. When user enter required info, change the status. This calls custom_func which triggers your interactive_task.
Related
For a project I'm trying to select the right output if a parameter of the created agent is true. The agent is created in the main but goes into a different agent for the selection of the output. If I use a select in the main and use the statement for the parameter as condition it works fine. Whenever it enters the agent and I use the same statement it gives an error (Description: product1 cannot be resolved or is not a field. Location: testCase5/Transport/selectOutput - SelectOutput).
I tried using different conditions like main.agent.product1 . Can't seem to solve the issue. I know that it has to do something with declaration probably but I'm clueless at the moment.
//for the condition that works if I put the selectOutput in the main
agent.product1
//for the condition in the agent I tried the same but didn't work. also tried
main.agent.product1 // Gives the same error but for (Description: agentcannot be resolved or is not a field.)
(Main)agent.product1
//And a few more
In AnyLogic each block of a project flow (regardless if from the process modeling library, the pedestrian library or another) has the type of Agent that is flowing through it defined in its properties. You can find this setting as Agent type in the block's properties under Advanced.
If you fail to set this correctly (meaning this setting equals the type of Agents you let flow through it), it will still flow through, BUT: you cannot access the specific properties of the Agent type.
That said, usually you do not even have to think about, because AnyLogic has an automatism there: The first block of your process flow, typically a Source-block or a Enter-block is the only block where you have to make the correct setting, all attached blocks get it then automatically!
However this does not work when:
You have separate flows (eg. you leave one flow through an Exit-block and enter another by an Enter). You'll manually have to put the correct setting also for the first block of the second process flow.
Your process flow is continued inside of another Agent/Custom Block, as in your example. AnyLogic doesnt realize the process flow inside your custom block is logically connected to the outside process flow in main. You have to specifiy manually again the Agent type flowing through in the first block of your process inside your Custom Block.
Suppose that we have a caller A and a callee B. B implements some function and has heavy dependencies.
Typically, I don't want to import these dependencies in A to keep it lightweight.
Previously, I can happily use send_task to call B by name.
Now I have more complex logic and wanna orchestrate tasks with canvas. Following the user guide here:
signature('tasks.add', args=(2, 2), countdown=10)
I got a task NotRegistered error.
How to register task by name?
Without seeing your code, we can't actually help you. So I'll answer your question generically using the docs:
For reference, here is the example snippet from celery:
from celery import Celery
app = Celery('tasks', broker='pyamqp://guest#localhost//')
#app.task
def add(x, y):
return x + y
Note that we create the signature tasks.add because the application is named tasks in the Celery constructor and the function is named add. This task is registered because it is in a tasks.py file. So, to call a task by name we have to make sure of three things:
Is the task registered properly? We can check by looking at the output when a celery worker starts, and the worker outputs a list of registered tasks. If not, make sure the task is in a tasks.py file or a tasks module that celery knows to look for.
What is my application name? We can find this by looking for the call to the Celery constructor. It is what you pass to the -A parameter when starting a worker.
What is my task name? If no name is specified in the app.task decorator, use the function name. Otherwise use the name specified in the app.task decorator.
After ensuring (1), concatenate (2) and (3), and put a . in between them to get the task name to call.
I have a many human task. After start the process i want to update some process variable value with rest API call that's relates to current task. If anyone knows how to do that commend bellow.
I try with /execute this is only start the task then how to update the process variable for already started process instance?
Based on the documentation
Here is how to do update the process variable. However, this will update an entire process rather than only that specific task.
server/containers/{id}/processes/instances/{pInstanceId}/variables - POST
If you want to update process variable from a task, you should do it during task completion. However, this requires you to have output variables from that task. Otherwise, it won't take any effect.
server/containers/{id}/tasks/{tInstanceId}/states/completed - PUT
Anyway, the full documentation of rest can be viewed in
{localhost}:{port}/kie-server/docs
I need to add an Action to a Schedule object that is being created through the API. There are documented interfaces to set almost all the options except the Action. How are Actions attached to these Objects?
When I attempt to programmatically add a new event, read from a separate configuration file, to a Schedule object I get errors stating that the Schedule has already been initialized and that I must construct a new object and add its configuration manually. I can do most of that using the available Schedule API. I can set up everything about the Schedule except the Action code.
The Schedule is used in a Process Model. Looking at the model in the Java editor, I see the code I'm trying to replicate via the API in a function that looks like this:
#Override
#AnyLogicInternalCodegenAPI
public void executeActionOf( EventTimeout _e ) {
if ( _e == _fuelDeliverySchedule_Action_xjal ) {
Schedule<Integer> self = this.fuelDeliverySchedule;
Integer value = fuelDeliverySchedule.getValue();
logger.info("{} received {} pounds of fuel", this.getName(), this.fuelDeliverySchedule.getValue());
this.fuelAvailablePounds += fuelDeliverySchedule.getValue();
;
_fuelDeliverySchedule_Action_xjal.restartTo( fuelDeliverySchedule.getTimeOfNextValue() );
return;
}
super.executeActionOf( _e );
}
Maybe I can use something like this to create my own action function, but I'm not sure how to make the Scheduled event use it.
Thanks,
Thom
[Edited (expanded/rewrote) 03.11.2014 after more user detail on the context.]
You clarified the context with
When I attempt to programatically add "a thing that happens", read
from a separate configuration file, to a Schedule object I get errors
stating that the Schedule has already been initialized and that I must
construct a new object and add its configuration manually. I can do
most of that using the available Schedule API. I can set up everything
about the Schedule except the Action code.
(You might want to edit that into the question... In general, it's always good to explain the context for why you're trying to do the thing.)
I think I understand now. I presume that your config file contains scheduling details and, when you say you were trying to "add a thing that happens" (which errored), you meant that you were trying to change the scheduling 'pattern' in the Schedule. So your problem is that, since you couldn't adjust a pre-existing schedule, you had to instantiate (create) your own programmatically, but the Schedule API doesn't allow you to set the action code (as seen on the GUI schedule element).
This is a fairly involved solution so bear with me. I give a brief 'tl;dr'
summary before diving into the detail.
Summary
You can't programmatically code an AnyLogic action (for any element) because that would amount to
dynamically creating a Java class. Solving your problem requires recognising
that the schedule GUI element creates both a Schedule instance and a
timeout event (EventTimeout) instance to trigger the action. You can therefore create these two elements explicitly yourself (the former dynamically). The trick is to reset the timeout event when you replace the Schedule instance (to trigger at the next 'flip' point of the new Schedule).
[Actually, from your wording, I suspect that the action is always the same but, for generality, I show how you could handle it if your config file details might want to change the nature of the action as well as those of the scheduling pattern.]
Detail
The issue is that the GUI element (confusingly) isn't just a Schedule instance
in terms of the code it generates. There is one (with the same name as that of
the GUI element), which just contains the schedule 'pattern' and, as in the API,
has methods to determine when the next on/off period (for an on/off schedule) occurs. (So
it is kind of fancy calendar functionality.) But AnyLogic also generates a
timeout event to actually perform the action; if you look further in the code
generated, you'll see stuff similar to the below (assuming your GUI schedule is called
fuelSchedule, with Java comments added by
me):
// Definition of the timeout event
#AnyLogicInternalCodegenAPI
public EventTimeout _fuelSchedule_Action_xjal = new EventTimeout(this);
// First occurrence time of the event as the next schedule on/off change
// time
#Override
#AnyLogicInternalCodegenAPI
public double getFirstOccurrenceTime( EventTimeout _e ) {
if ( _e == _fuelSchedule_Action_xjal ) return fuelSchedule.getTimeOfValue() == time() ? time() : fuelSchedule.getTimeOfNextValue();
return super.getFirstOccurrenceTime( _e );
}
// After your user action code, the event is rescheduled for the next
// schedule on/off change time
_fuelSchedule_Action_xjal.restartTo( fuelSchedule.getTimeOfNextValue() );
i.e., this creates an event which triggers each time the schedule 'flips', and performs the action specified in the GUI schedule element.
So there is no action to change on the Schedule instance; it's actually related to the EventTimeout instance. However, you can't programmatically change it there (or create a new one dynamically) for the same reason that you can't change the action of any AnyLogic element:
this would effectively be programmatically
creating a Java class definition, which isn't possible without very specialised
Java code. (You can create Java source code in a string and
dynamically run a Java compiler on it to generate a class. However, this is very
'advanced' Java, has lots of potential pitfalls, and I would definitely not
recommend going that route. You would also have to be creating source for a user subclass
of EventTimeout, since you don't know the correct source code for AnyLogic's proprietary EventTimeout class, and this might change per release in any case.)
But you shouldn't need to: there should be a strict set of possible actions that your config file can contain. (They can't be arbitrary Java code snippets, since they have to 'fit in' with the simulation.) So you can do what you want by programmatically creating the Schedule but with a GUI-created timeout event that you adjust accordingly(assuming an off/on schedule here and that there is
only one schedule active at once; obviously tweak this skeleton to your needs
and I haven't completely tested this in AnyLogic):
1. Have an AnyLogic variable activeAction which specifies the current active
action. (I take this as an int here for simplicity, but it's better to use a
Java enum which is the same as an AnyLogic 7 Option List, and can just be
created in raw Java in AnyLogic 6.)
2. Create a variable in the GUI, say called fuelSchedule, of type Schedule but with initial value null. Create a separate timeout event, say called fuelScheduleTrigger, in User Control mode, with action as:
// Perform the appropriate action (dependent on activeAction)
doAppropriateScheduleAction();
// Set the event to retrigger at the next schedule on/off switch time
fuelScheduleTrigger.restartTo(fuelSchedule.getTimeOfNextValue());
(Being in User Control mode, this event isn't yet triggered to initially fire, which is what we want.)
3. Code a set of functions for each of the different action alternatives; let's say
there are only 2 (fuelAction1 and fuelAction2) here as an example. Code
doAppropriateScheduleAction as:
if (activeAction == 1) {
fuelAction1();
}
else if (activeAction == 2) {
fuelAction2();
}
4. In your code which reads the config file and gets updated schedule info.
(presumably run from a cyclic timeout event or similar), have this replace
fuelSchedule with a new instance with the revised schedule pattern (as you've
been doing), set activeAction appropriately, and then reset the timeout event to
the new fuelSchedule.getTimeOfValue() time:
[set up fuelSchedule and activeAction]
// Reset schedule action to match revised schedule
fuelScheduleTrigger.restartTo(fuelSchedule.getTimeOfNextValue());
I think this works OK in the edge case when the new Schedule had its next 'flip' at the time
you set it up. (If you restart an event to the current time, I think it schedules an event OK at the current time which will occur next if there are no other events also scheduled for the current time; actually, it will definitely occur next if you are using a LIFO simultaneous-time-scheduling regime---see my blog post.)
Alternative & AnyLogic Enhancement
An alternative is to create a 'full' schedule in the GUI with action as earlier. Your config file reading code can replace the underlying Schedule instance and then reset the internal AnyLogic-generated timeout event. However, this is less preferable because you are relying on an internally-named AnyLogic event (which might also change in future AnyLogic releases, breaking your code).
AnyLogic could help this situation by adding a method to the Schedule API that gets the related timeout event; e.g., getActionTriggeringEventTimeout(). Then you would be able to 'properly' restart it and the Schedule API would make much clearer that the Schedule was always associated with an EventTimeout that did the triggering for the action.
Of course, AnyLogic could also go further by changing Schedule to allow scheduling details to be changed dynamically (and internally handling the required updates to the timeout event if it continued to be designed like that), but that's a lot more work and there may be deeper technical reasons why they wanted the schedule pattern to be fixed once the Schedule is initialised.
Any AnyLogic support staff reading?
I am new to Jbpm 5.4. I want to set a process variable after completing one Human task. I know we can add process variables at start up using a map. Can any one tell me how set process variable in the middle of the process please???
Result mapping & data associations. Like any other type of task.
See
https://docs.jboss.org/jbpm/v5.4/userguide/ch.human-tasks.html#d0e4970
Result mapping: Allows copying the value of result parameters of the
human task to a process variable. Upon completion of the human task,
the values will be copied. A human task has a result variable "Result"
that contains the data returned by the human actor. The variable
"ActorId" contains the id of the actor that actually executed the
task.
also
https://github.com/droolsjbpm/jbpm/blob/master/jbpm-bpmn2/src/test/resources/BPMN2-DataOutputAssociations.bpmn2
for an example