How to use channel to realize a connection pool in golang
This article introduces how to use channel to achieve a connection pool in golang, the content is very detailed, interested friends can refer to, hope to be helpful to you.
What is universal?
The implementation of connection pool does not depend on a specific instance, but on an interface. The connection pool in this paper chooses the io.Closer interface, as long as the objects that implement this interface can be managed by the pool.
Of course, you can implement connection pooling based on interface {} so that any object can be managed.
Realization principle
The connection handle is stored in channel. Due to the nature of caching channel, if there is a connection in the pool, it will be returned directly. If there is no connection in the pool, it will block or create a new connection (if the maximum limit is not exceeded).
Because of interface-oriented programming, all the logic for creating connections is unclear, so you need to pass in a function that returns an io.Closer object.
Realize
Due to concurrency problems, locks are needed when mutually exclusive data in the operation pool is needed.
Package pool
Import (
"errors"
"io"
"sync"
"time"
)
Var (
ErrInvalidConfig = errors.New ("invalid pool config")
ErrPoolClosed = errors.New ("pool closed")
)
Type factory func () (io.Closer, error)
Type Pool interface {
Acquire () (io.Closer, error) / / get resources
Release (io.Closer) error / / release resources
Close (io.Closer) error / / close resources
Shutdown () error / / shuts down the pool
}
Type GenericPool struct {
Sync.Mutex
Pool chan io.Closer
Maximum number of resources in maxOpen int / / pool
NumOpen int / / number of resources in current pool
Minimum number of resources in minOpen int / / pool
Whether the closed bool / / pool is closed
MaxLifetime time.Duration
Factory factory / / method of creating a connection
}
Func NewGenericPool (minOpen, maxOpen int, maxLifetime time.Duration, factory factory) (* GenericPool, error) {
If maxOpen maxOpen {
Return nil, ErrInvalidConfig
}
P: = & GenericPool {
MaxOpen: maxOpen
MinOpen: minOpen
MaxLifetime: maxLifetime
Factory: factory
Pool: make (chan io.Closer, maxOpen)
}
For I: = 0; I < minOpen; iTunes + {
Closer, err: = factory ()
If err! = nil {
Continue
}
P.numOpenbones +
P.pool
