Search Tasks based on task details

Summary

IBM BAW does not allow to search tasks based on criterias that correspond to values of

business data attached to the tasks.

For instance, if a task has a “JobCode” business data, there is no API that allows to search all

task instances across all process instances with a “JobCode” equals to “XYZ”.

The workaround to get all tasks for all processes, iterate on each task, get the task detail to

find the searched task is extremely costly when the number of processes/tasks is big.

The ask it to have a REST API, similar to what exist at process level, to find all tasks with a

given list of criterias.

The limitation has already been raised in the community:

https://community.ibm.com/community/user/automation/discussion/search-in-baw-tasks-

with-filter-in-task-scope-not-process-instance-scope-using-baw-rest-exposed-services

Context

BPCE is using IBM BAW as the foundation for their new Workflow system with the objective

to implement their business workflows and orchestrate work from their agents. Ultimately,

thousands of processes and tens of thousands of tasks will be in-flight at any given time.

Business Requirements

Process participants in the bank can be assigned task. A given employee might have several

Job Roles and tasks are assigned to a given employee for a given Job Role.

The requirement is to give a workflow participant the ability to find all tasks that are

assigned to him for a given Job Role.

This is one example of a business requirement that require searching for tasks based on the

details of a task. To efficiently fulfil his mission, a workflow participant might have to get

access to all tasks according to one or several criteria. These criteria correspond to task-level

business data.

What can’t be done today

A developer using IBM BAW APIs doesn’t have an API to find all tasks where the value of a

business data attached to the task correspond to a given value.

Technical limitations

There is no API in BAW to find all task instances across all process instances where the value

of a variable attached to the task is equal to a given value.

There is an API to find all tasks with a criteria based on predefined task attribute (like status

or others), but not for business data attached to the task.

There is an API to find all task instances across all process instances, but, when the product

is deployed at scale, this can bring a very large number of task instances and iteration on

each of them is extremely time consuming.

This kind of API exists to find all process instances where the value of a process-level

variable is a given value. A workaround that has been explored is to copy on process-level

variables the value of task-level variable so that it can be searched using the process-level

search API. However, has multiple instances of a given task with different values for their

variables can be run in parallele, those copy would have to be stored on multi-valued

process-level variables. However, this API does not allow to test a criteria on elements of

multi-valued (list) variables, which makes this workaround not viable.

Directly accessing the BAW database to find these tasks is not possible because task details

stored in the database (values of task-level variables) is stored as a blob which is the result

of the serialisation of a Java class, making it opaque and not searchable.

The only workaround identified to far is to build a separate system of records of all tasks

that would allow more flexibility in queries, and maintain it as task evolve. This new

database of task would be built and maintained based on the events sent by BAW when

tasks are instantiated and modified. However, some data in task details can’t be tracked

(multi-valued variable for instance), which might lead to missing updates to maintain this

database. Although this issue might be workarounded, building and maintaining this

separate database is a significant effort that would not be necessary if the search API for

task was more powerful.