example_service = almanet.new_service(
    "localhost:4150",
    prepath="net.example"
)

Arguments:

• the TCP addresses of the NSQ instances
• prepath for the service's procedures, helping in identifying and organizing them

class denied(almanet.rpc_error):
    """Custom RPC exception"""

This custom exception can be raised within procedures to signal specific error conditions to the caller.

@example_service.procedure
async def greeting(
    session: almanet.Almanet,
    payload: str,
) -> str:
    """Procedure that returns greeting message"""
    if payload == "guest":
        raise denied()
    return f"Hello, {payload}!"

Decorator @example_service.procedure registers the greeting function as a remote procedure for the example_service.

Arguments:

• payload is a data that was passed during invocation.
• session is a joined service, instance of almanet.Almanet

It raises the custom denied exception, indicating that this payload is not allowed if payload is "guest". Otherwise, it returns a greeting message.

if __name__ == "__main__":
    example_service.serve()

Starts the service, making it ready to handle incoming RPC requests.

Run your module using the python command

session = almanet.new_session("localhost:4150")

Arguments:

• the TCP addresses of the NSQ instances

async with session:
    result = await session.call("net.example.greeting", "Aidar")
    print(result.payload)

async with session ensures that the session is properly managed and closed after use. Calls the remote procedure net.example.greeting with the payload "Aidar". Raises TimeoutError if procedure not found or request timed out. result.payload contains the result of the procedure execution.

async with session:
    try:
        await session.call("net.example.greeting", "guest")
    except almanet.rpc_error as e:
        print("during call net.example.greeting('guest'):", e)

The try block attempts to call the net.example.greeting procedure with the payload "guest". If an exception occurs during the call, specifically an almanet.rpc_error, it is caught by the except block.

Run your module using the python command