Interface IEventHubStorageProvider<TStorageRecord>
interface for implementing a storage provider for event hub app (gRPC server)
Namespace: FastEndpoints
Assembly: FastEndpoints.Messaging.Remote.dll
Syntax
public interface IEventHubStorageProvider<TStorageRecord> where TStorageRecord : IEventStorageRecordType Parameters
| Name | Description |
|---|---|
| TStorageRecord | the type of the storage record |
Methods
GetNextBatchAsync(PendingRecordSearchParams<TStorageRecord>)
fetch the next batch of pending event storage records that need to be processed.
Declaration
ValueTask<IEnumerable<TStorageRecord>> GetNextBatchAsync(PendingRecordSearchParams<TStorageRecord> parameters)Parameters
| Type | Name | Description |
|---|---|---|
| PendingRecordSearchParams<TStorageRecord> | parameters | use these supplied search parameters to find the next batch of event records from your database |
Returns
| Type | Description |
|---|---|
| ValueTask<IEnumerable<TStorageRecord>> |
MarkEventAsCompleteAsync(TStorageRecord, CancellationToken)
mark the event storage record as complete by either replacing the entity on storage with the supplied instance or simply update the IsComplete field to true with a partial update operation.
Declaration
ValueTask MarkEventAsCompleteAsync(TStorageRecord r, CancellationToken ct)Parameters
| Type | Name | Description |
|---|---|---|
| TStorageRecord | r | |
| CancellationToken | ct | cancellation token |
Returns
| Type | Description |
|---|---|
| ValueTask |
PurgeStaleRecordsAsync(StaleRecordSearchParams<TStorageRecord>)
this method will be called hourly. implement this method to remove stale records (completed or expired) from storage. or instead of removing them, you can move them to some other location (dead-letter-queue maybe) or for inspection by a human. or if you'd like to retry expired events, update the ExpireOn field to a future date/time.
NOTE: the default match criteria is:
r => r.IsComplete || DateTime.UtcNow >= r.ExpireOnDeclaration
ValueTask PurgeStaleRecordsAsync(StaleRecordSearchParams<TStorageRecord> parameters)Parameters
| Type | Name | Description |
|---|---|---|
| StaleRecordSearchParams<TStorageRecord> | parameters | use these supplied search parameters to find relevant event records from your database |
Returns
| Type | Description |
|---|---|
| ValueTask |
RestoreSubscriberIDsForEventTypeAsync(SubscriberIDRestorationParams<TStorageRecord>)
this method will only be called once (for each event type) on app startup. if there are any pending records on storage from a previous app run, simply return a collection of unique subscriber IDs.
Declaration
ValueTask<IEnumerable<string>> RestoreSubscriberIDsForEventTypeAsync(SubscriberIDRestorationParams<TStorageRecord> parameters)Parameters
| Type | Name | Description |
|---|---|---|
| SubscriberIDRestorationParams<TStorageRecord> | parameters | use these supplied search parameters to find relevant event records from your database |
Returns
| Type | Description |
|---|---|
| ValueTask<IEnumerable<string>> |
StoreEventsAsync(IEnumerable<TStorageRecord>, CancellationToken)
store the event storage records however you please. ideally on a nosql database.
WARNING: make sure to use a transaction or batch insert to ensure all the records are committed in one go. if only some of the records succeed in being stored, it could lead to duplicate events being published due to the built-in retry mechanism.
Declaration
ValueTask StoreEventsAsync(IEnumerable<TStorageRecord> r, CancellationToken ct)Parameters
| Type | Name | Description |
|---|---|---|
| IEnumerable<TStorageRecord> | r | the event storage records which contains the actual event objects as well as some metadata |
| CancellationToken | ct | cancellation token |
Returns
| Type | Description |
|---|---|
| ValueTask |