Cratis Chronicle .NET clients for short-lived processes

Use the Cratis Chronicle .NET short-lived preset for a tool, function, or job that connects, appends or reads events, and exits without hosting reactors or reducers. It disables the keep-alive stream and watchdog that long-running clients use to detect a lost connection.

Using the preset

In an application referencing Cratis.Chronicle, use ChronicleOptions.ForShortLivedProcess from the Cratis.Chronicle namespace. This example assumes the local kernel is running and SomethingHappened is one of your application’s declared event types:

var options = ChronicleOptions.ForShortLivedProcess("chronicle://localhost:35000");
using var client = new ChronicleClient(options);
var eventStore = await client.GetEventStore("my-store");

await eventStore.EventLog.Append("source", new SomethingHappened());

ForShortLivedProcess sets SkipKeepAlive and defaults RegistrationMode to Inline. It leaves AutoDiscoverAndRegister and SkipCompatibilityCheck unchanged, so it does not disable discovery or the compatibility check. For options you are configuring directly, call UseShortLivedProcess(); this example also limits registration to event types:

var options = new ChronicleOptions().UseShortLivedProcess(RegistrationMode.EventTypesOnly);

What the client does not do

Without keep-alive, the kernel has no live connection on which to deliver events to this process. The client therefore:

• opens no keep-alive stream and no watchdog
• does not register reactors, reducers, read model reactors or occurrences, and does not subscribe to external event stores
• throws ClientObserversRequireKeepAlive if you register a reactor or reducer explicitly, or nominate one through ExplicitArtifacts

You can still append and read events. Host reactors and reducers in a long-running service that keeps keep-alive enabled; they cannot receive events through this short-lived client.

Choosing how to register

RegistrationMode decides what the process registers when it connects.

Mode	What happens
Inline	Registers discovered artifacts except the client-hosted observers excluded above. The default.
EventTypesOnly	Ensures the event store exists and registers the event types only.
AtDeployment	Registers nothing; uses artifacts registered by another process at deployment time.

Choose EventTypesOnly when the process needs to register its events but should not register projections, constraints, and read models on every start. Choose AtDeployment when another process has already registered the definitions; register definitions as a deployment step explains that workflow. RegistrationMode only has an effect when AutoDiscoverAndRegister is enabled.

For functions and other scaled-to-zero hosts, see Serverless mode, which builds on this preset.

From a connection string

The same keep-alive behavior is available from the connection string with skipKeepAlive=true, and from the builder with WithKeepAliveSkipped(). See connection strings.