Activiti Cloud Query Service
The Query Service enable client applications to get Process & Task data without going straight to the Runtime Bundles. The Query Service was designed to enable efficient querying mechanisms for data generated by one or more Runtime Bundles. In contrast with the Audit Service, the Query Service picks up the event and apply some transformations to store state.
This component was designed to aggregate data from a set of related Runtime Bundles, allowing consumers to filter using the runtime bundle.
Specification
Endpoints
The query component provides read only REST endpoints.
Event Listeners
The query service listen to events generated by runtime bundles and transform them to store state about the current process instances and tasks executions. This state is stored in a schema that is optimized for querying and based on the specification of this component different implementations using different technologies can be implemented.
Our reference implementation uses JPA entities to store this state and we defined a simple schema to store the state of the following entities:
Here you can find all the Events Listeners that are used to recreate state from the events emitted by the Runtime Bundle.
These event listeners have the responsability of understanding each specific event and apply a transformation to the existing entities or creating new entity instances. The following section explains the current flow for each of the listeners. You can provide your own implementation of the Query Service (in any other language), by following the described behaviour:
This handler will
Create a new ProcessDefinitionEntity and
Set Cloud Metadata:
ServiceName
ServiceFullName
ServiceVersion
AppName
AppVersion
Set Id
Set Description
Set FormKey
Set ProcessDefinitionKey
Set Name
Set Version
Set Service Type
Create a new ProcessModelEntity and
Set ModelContent
Set Link to ProcessDefinitionEntity
This handler will:
Create a new ProcessInstanceEntity and
Set Cloud Metadata:
ServiceName
ServiceFullName
ServiceVersion
AppName
AppVersion
Set Id
Set ProcessDefinitionId
Set ProcessDefinitionKey
Set ProcessDefinitionVersion
Set Status to CREATED
Set LastModified to the date inside the event
Set Name
Set Initiator
Set BusinessKey
Set StartDate
Set ParentId
This handler will:
Update an existing ProcessInstanceEntity
Check if there is a Process Instance with status CREATED and:
Update the Status to RUNNING
Set the name of the process instance
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Update an existing ProcessInstanceEntity and
Update BusinessKey
Update Name
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Update an existing ProcessInstanceEntity and
Update Status to SUSPENDED
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Update an existing ProcessInstanceEntity and
Update Status to RUNNING
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Update an existing ProcessInstanceEntity and
Update Status to CANCELLED
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Update an existing ProcessInstanceEntity and
Update Status to COMPLETED
Update LastModified
This event will be discarded if no Process Instance is not found and QueryException will be thrown
This handler will:
Will check if it is a Task Var
Security and Permissions
By default only admin users can access everything. The endpoints that under /admin/ can be accessed ACTIVITI_ADMIN roles.
Process instance, task and variable data can be restricted to particular users or groups. This can be done by adding properties such as:
Here rb-app-name is the name of a runtime bundle application. Or environment variables can be used such as
ACTIVITI_CLOUD_SECURITY_USER_HRUSER_RBMYAPP_POLICY_READ=SimpleProcess ACTIVITI_CLOUD_SECURITY_GROUP_HR_RBMYAPP_POLICY_WRITE=SimpleProcess ACTIVITI_CLOUD_SECURITY_GROUP_TESTGROUP_RBMYAPP_POLICY_WRITE=*
Implementations
Activiti Cloud Query Service - ElasticSearch PR Under Review
Docker Images
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