Agent Methods

Introduction

These methods are related to checking the access of an Agent, before using it.

This methods are accessed via the “n2.n2svcd” module:

    local n2svcd = require "n2.n2svcd"

.agent_access [Asynchronous]

The agent_access method checks the application access level of a Lua Agent.

In all practical terms this means checking the application access of the underlying “other” n2svcd applications which this agent uses to perform its function. For example, a DB agent will use a DBApp to perform its function, and hence will consider the DBApp’s access when returning the agent access value.

An agent which does not rely on other n2svcd applications to perform its function will always return ACCESS_ONLINE.

The agent_access method takes the following parameters.

Example:

    local db_access = n2svcd.agent_access ("db")

The agent_access method returns one of the following application access constants.

-- # Application is Starting Up or Shutting Down.
-- # We will reject ALL user messages.  We will still accept management messages.
n2svcd.ACCESS_SHUTDOWN = 0

-- # Application is not currently available to perform functions.
-- # It is almost certain that any user request you give us will fail.
n2svcd.ACCESS_OFFLINE = 1

-- # Application is Quiescing.  Shutdown Notice received, or user-requested.
-- # We will reject ALL new user session but will complete existing transactions.
n2svcd.ACCESS_QUIESCING = 2

-- # Application has some/full connectivity and you can send requests.
-- # If you have a choice of more than one ONLINE application you should look at that load %.
n2svcd.ACCESS_ONLINE = 3

.agent_online [Asynchronous]

A simplified version of agent_access which returns true when the agent is ACCESS_ONLINE and false otherwise.

The agent_online method takes the following parameters.

    local alt_online = n2svcd.agent_online ("db", "alt")