Pool

new Pool(options, min, max, max_queue, timeout, idle)

Description:

• Create a resource pool, create and close callbacks must be given which perform allocation and deallocation of the resources like db connections.

Parameters:

Name	Type	Description
options	object	defines the following properties Properties Name Type Attributes Description create function <optional> method to be called to return a new resource item, takes 1 argument, a callback as function(err, item) destroy function <optional> method to be called to destroy a resource item reset function <optional> method to be called just before releasing an item back to the resource pool, this is a chance to reset the item to the initial state validate function <optional> method to verify active resource item, return false if it needs to be destroyed init function <optional> method to cal on pool.init, it may be called multiple times shutdown function <optional> method to call on pool shutdown to clear other resources
min	int	min number of active resource items
max	int	max number of active resource items
max_queue	int	how big the waiting queue can be, above this all requests will be rejected immediately
timeout	int	number of milliseconds to wait for the next available resource item, cannot be 0
idle	int	number of milliseconds before starting to destroy all active resources above the minimum, 0 to disable. If no create implementation callback is given then all operations are basically noop still calling the callbacks.

Example

var pool = new Pool({
    min: 1,
    max: 5,
    create: function(cb) {
        someDb.connect((err) => { cb(err, this) }
    },
    destroy: function(client) {
        client.close() }
    })
});

pool.use((err, client) => {
    ...
    pool.release(client);
});

const { err, client } = await pool.ause();
if (!err) {
    ...
    pool.release(client);
}