The title is pretty explanatory. I want a batch which will execute everyday, at the same hour. Like a batch.
Also, is it possible to have a smart contract with endpoints and batch executing inside?
Currently there is no way to schedule a smart contract execution inside a smart contract.
Meaning if you want to call a function in the smart contract you have to send a transaction to the smart contract. To achieve this at the same time everyday you would have to use something like a cronjob on a traditional backend.
Not sure what you mean with endpoints and batch executing, but you can also make read only functions using the #[view] makro, instead of the #[endpoint] makro you would normally use for public functions. These view functions can be called without requiring a transaction using the query endpoint.
And of course you can use loops inside your smart contract to execute a bunch of things at the same time.
Related
Lets assume I have defined the routing slip activity. Within Execute method I would like to make several asynchronous service calls. Lets assume 3 service calls. Two of them succeed and one fails. Then I would like to execute compensate action of this activity in order to compensate the changes introduced by two succeeded service calls. From what I see the compensation only runs for previous activities, the current activity compensation has no chance to be invoked when there is exception somewhere in it. Is there a way to deal with it or I should change the approach?
I would like to achive sth similar to
using MassTransit.
You should have three separate activities, and execute them in order, so that as they succeed individually, they are added to the log. If an activity fails, the previous activities will be compensated.
By having all three calls in a single activity, you're going against the entire reason for having the routing slip and activities.
I have a MassTransit system that will consume 2 message types, one for a batch process, the other for CRUD operations on a single entity. Whilst the batch process is running, the CRUD operations should not be de-queued.
Is this possible to achieve using MassTransit? It seems the exchange binding -> type name, would potentially make this behavior difficult.
A solution would be to use one message type to denote both operations and then interrogate the message contents to discern between single and batch but this feels like a code smell. Also, this would require concurrency configuration to ensure only one consumer is ever active.
Can anyone help with an alternative solution here? Essentially, we need to pause all message consumption whilst an event driven process is running.
Thanks in advance.
By pause, do you mean that you want the CRUD operations to be able to occur without being blocked by the batch process? Because if it's only a matter of not having the two separate messages get in the way of each other, the most logical solution is using two separate queues, one receive endpoint for the batch process and another for the CRUD operations.
Now, if you truly need to separate the batch process such that it doesn't happen during the CRUD operations, that will require more work. And what if you receive a CRUD operation while the batch process is already running?
I think the separate queues is your best solution, however.
This answer from Parse says:
You can call destroy() on any ParseObject from Cloud Code to delete them. Deleting, as well as creating or updating, multiple objects from Cloud Code is not recommended, however.
Why? The answerer doesn't say, and it seems like Cloud Code would be exactly the place to bulk update/delete objects. Is he using Cloud Code in opposition to a Cloud background job? Or am I missing some other way to delete objects in Parse?
The linked answer was from before the launch of Background Jobs, which have an increased time-limit.
Cloud Functions have a 15 second maximum run-time. This is why you need to be a little conservative about how many operations you perform in a specific cloud function.
Now, Background Jobs are the recommended path for maintenance-type processes. https://parse.com/docs/cloud_code_guide#jobs
They have a 15 minute time limit, and if you're clever about it, can be used to handle lots of work at near-real-time speeds. i.e. https://gist.github.com/gfosco/131974d200c5e9fc6c94
I need to know the relative position of an object in a list. Lets say I need to know the position of a certain wine of all wines added to the database, based in the votes received by users. The app should be able to receive the ranking position as an object property when retrieving a "wine" class object.
This should be easy to do in the backend side but I've seen Cloud Code and it seems it only is able to execute code before or after saving or deleting, not before reading and giving response.
Any way to do this task?. Any workaround?.
Thanks.
I think you would have to write a Cloud function to perform this calculation for a particular wine.
https://www.parse.com/docs/cloud_code_guide#functions
This would be a function you would call manually. You would have to provide the "wine" object or objectId as a parameter and then get have your cloud function return the value you need. Keep in mind there are limitations on cloud functions. Read the documentation about time limits. You also don't want to make too many API calls every time you run this. It sounds like your computation could be fairly heavy if your dataset is large and you aren't caching at least some of the information.
I'm trying to follow TDD (i'm newbee) during development of Service class which builds tasks passed by Service clients. The built objects are then passed to other systems. In other words this service takes tasks but returns nothing as a result - it passes built tasks to other Services.
So I'm wondering how can I write test for it because there is nothing to assert.
I'm thinking about using mocks to track interactions inside the service but I'm a little bit afraid of using mocks because I will be tied up with internal implementarion of the service.
Thanks all of you in advance!
There's no problem using mocks for this, since you are effectively going to be mocking the external interface of the components that are used internally in the component. This is really what mocking is intended for, and sound like a perfect match for your use case.
When doing TDD it should also allow you to get those quick turnaround cycles that are considered good practice, since you can just create mocks of those external services. These mocks will easily allow you to write another failing test.
You can consider breaking it up in a couple classes. One responsible to build the list of tasks that will be executed, and the other responsible to execute the list of tasks it is handed. This way you can directly test the code that build the lists of tasks.
That said, I want to add a sample I posted on another question, regarding how I view the TDD process when external systems are involved.
Lets say you have to check whether
some given logic sends an email, logs
the info on a file, saves data on the
database, and calls a web service (not
all at once I know, but you start
adding tests for each of those). On
each test you don't want to hit the
external systems, what you really want
to test is if the logic will make the
calls to those systems that you are
expecting it to do. So when you write
a test that checks that an email is
sent when you create an user, what you
test is if the logic calls the
dependency that does that. Notice that
you can write these tests and the
related logic, without actually having
to implement the code that sends the
email (and then having to access the
external system to know what was sent
...). This will help you focus on the
task at hand and help you get a
decoupled system. It will also make it
simple to test what is being sent to
those systems.
Not sure what language you're using so in psuedo-code it could be something like this:
when_service_is_passed_tasks
before_each_test
mockClients = CreateMocks of 3 TaskClients
tasks = GetThreeTasks()
myService = new TaskRouter(mockClients)
sends_all_to_the_appropriate_clients
tasks = GetThreeTasks()
myService.RouteTaks(tasks)
Assert mockClients[0].AcceptTask(tasks[0]) was called
Assert mockClients[1].AcceptTask(tasks[1]) was called
Assert mockClients[2].AcceptTask(tasks[2]) was called
if_one_routing_fails_all_fail
tasks = GetTasksWhereOneIsFailing()
myService.RouteTaks(tasks)
Assert mockClients[0].AcceptTask(*) was not called
Assert mockClients[1].AcceptTask(*) was not called
Assert mockClients[2].AcceptTask(*) was not called