inventory/

Inventory: calls, callbacks, and notifications

This is the two-process starting example. The client and server import a shared contract, so request and response types are not duplicated.

It demonstrates:

• A synchronous call with a deadline.
• A server-to-client notification over the same connection.
• An async call with a caller-owned correlation ID and a bounded callback wait.
• A structured not_found error inspected with errors.As.
• Client cleanup and signal-driven server shutdown.

Run

From the repository root, start the server:

go run ./examples/inventory/server

It prints listening on 127.0.0.1:9070. In a second terminal:

go run ./examples/inventory/client

Expected client output:

widget-001: Widget Pack
server push: widget-001
async request-2: widget-async: Widget Pack
server push: widget-async
missing item: not_found (item not found)

The client exits after the demonstration; Ctrl-C stops the server. To use another port, pass the same -addr 127.0.0.1:9080 to both commands. The client's ten-second context also bounds initial connection attempts when no server is available.

Read the code

1. api/api.go defines the types and dispatch names both sides import.
2. server/main.go registers a handler and runs until interrupted.
3. client/main.go registers its notification handler before connecting, then performs the three requests.

The notification callback and async response callback send values into bounded channels; the main goroutine prints them. Waiting for the notification in this demo makes its output repeatable. It does not change notification semantics: the sender receives no remote acknowledgment.

AsyncCallContext bounds sending, not the response callback wait. This example bounds that wait separately and closes its client on return. A shared, long-lived client needs its own policy for late callbacks; for a simple bounded request/response operation, use CallContext.

Shutdown cancels active work and waits for handlers within a fresh three-second context. It does not drain calls to successful completion.

Optional authentication

Set the same environment variable in both terminals, then rerun the commands:

export GORPC_EXAMPLE_SECRET='local-demo-secret'

An unset variable leaves this loopback example unauthenticated. A mismatched secret causes authentication to fail. The literal above is only a local demonstration value; real applications should load their own secret.

Shared-secret authentication proves the dialer's knowledge of the secret. It does not encrypt traffic, authenticate the server to the client, or grant per-function permissions. See the service checklist.

Next

Try server streaming for slow readers and cancellation, or read calls and notifications for the full API choices.