API reference / @node-ts/bus-core / InMemoryPersistence

Class: InMemoryPersistence

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:21

A non-durable in-memory persistence for storage and retrieval of workflow state. Before using this, be warned that all workflow state will not survive a process restart or application shut down. As such this should only be used for testing, prototyping or handling unimportant workflows.

Implements

• Persistence

Constructors

Constructor

new InMemoryPersistence(): InMemoryPersistence;

Returns

InMemoryPersistence

Methods

getWorkflowState()

getWorkflowState<WorkflowStateType, MessageType>(
   workflowStateConstructor, 
   messageMap, 
   message, 
   attributes, 
   includeCompleted?
): Promise<WorkflowStateType[]>;

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:39

Retrieves all workflow state models that match the given messageMap criteria

Type Parameters

Type Parameter
WorkflowStateType extends WorkflowState
MessageType extends Message

Parameters

Parameter	Type	Description
workflowStateConstructor	ClassConstructor<WorkflowStateType>	The workflow model type to retrieve
messageMap	MessageWorkflowMapping<MessageType, WorkflowStateType>	How the message is mapped to workflow state models
message	MessageType	The message to map to workflow state
attributes	MessageAttributes	-
includeCompleted?	boolean	If completed workflow state items should also be returned. False by default

Returns

Promise<WorkflowStateType[]>

the matching workflow state as it was saved. The bus restores its classes, so it doesn't need to be converted.

Implementation of

Persistence.getWorkflowState

---

initializeWorkflow()

initializeWorkflow<TWorkflowState>(workflowStateConstructor, _): Promise<void>;

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:31

Allows the persistence implementation to set up its internal structure to support the workflow state that it will be persisting. Typically for a database this could mean setting up the internal table schema to support persisting of each of the workflow state models.

Type Parameters

Type Parameter
TWorkflowState extends WorkflowState

Parameters

Parameter	Type
workflowStateConstructor	ClassConstructor<TWorkflowState>
_	MessageWorkflowMapping<Message, WorkflowState>[]

Returns

Promise<void>

Implementation of

Persistence.initializeWorkflow

---

length()

length(workflowStateConstructor): number;

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:122

Gets the number of workflow states held in memory for a workflow state type

Parameters

Parameter	Type	Description
workflowStateConstructor	ClassConstructor<WorkflowState>	the type of workflow state to count

Returns

number

the number of workflow states held, including completed ones

Throws

WorkflowStateNotInitialized if the workflow state hasn't been initialized

---

prepare()

prepare(coreDependencies): void;

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:25

An optional function that is called before startup that will provide core dependencies to the persistence. This can be used to fetch loggers etc that are used in initialization steps. A persistence shared by several buses is prepared by each of them.

Parameters

Parameter	Type	Description
coreDependencies	CoreDependencies	the dependencies of the bus that's preparing the persistence

Returns

void

Implementation of

Persistence.prepare

---

saveWorkflowState()

saveWorkflowState<WorkflowStateType>(workflowState): Promise<void>;

Defined in: packages/bus-core/src/workflow/persistence/in-memory-persistence.ts:78

Saves a copy of the workflow state with its $version incremented. The $version of the state being saved must match the version held in memory, in the same way as durable persistence adapters enforce optimistic concurrency.

Type Parameters

Type Parameter
WorkflowStateType extends WorkflowState

Parameters

Parameter	Type	Description
workflowState	WorkflowStateType	the workflow state to save

Returns

Promise<void>

Throws

WorkflowStateNotInitialized if the workflow state hasn't been initialized

Throws

WorkflowStateVersionConflict if the workflow state was saved elsewhere since it was read

Implementation of

Persistence.saveWorkflowState