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Add connPool implementation and connection pool errors

Introduce connPool struct and implement the Pool interface. Add error handling for invalid pool capacity settings and provide a constructor for creating new connection pools with specified capacities.
This commit is contained in:
Winni Neessen 2024-09-22 21:12:59 +02:00
parent 5ec8a5a5fe
commit 26ff177fb0
Signed by: wneessen
GPG key ID: 385AC9889632126E

View file

@ -4,12 +4,20 @@
package mail
import "net"
import (
"errors"
"net"
"sync"
)
// Parts of the connection pool code is forked from https://github.com/fatih/pool/
// Thanks to Fatih Arslan and the project contributors for providing this great
// concurrency template.
var (
ErrPoolInvalidCap = errors.New("invalid connection pool capacity settings")
)
// Pool interface describes a connection pool implementation. A Pool is
// thread-/go-routine safe.
type Pool interface {
@ -25,3 +33,57 @@ type Pool interface {
// Len returns the current number of connections of the pool.
Len() int
}
// connPool implements the Pool interface
type connPool struct {
// mutex is used to synchronize access to the connection pool to ensure thread-safe operations
mutex sync.RWMutex
// conns is a channel used to manage and distribute net.Conn objects within the connection pool
conns chan net.Conn
// dialCtx represents the actual net.Conn returned by the DialContextFunc
dialCtx DialContextFunc
}
// NewConnPool returns a new pool based on buffered channels with an initial
// capacity and maximum capacity. The DialContextFunc is used when the initial
// capacity is greater than zero to fill the pool. A zero initialCap doesn't
// fill the Pool until a new Get() is called. During a Get(), if there is no
// new connection available in the pool, a new connection will be created via
// the corresponding DialContextFunc() method.
func NewConnPool(initialCap, maxCap int, dialCtxFunc DialContextFunc) (Pool, error) {
if initialCap < 0 || maxCap <= 0 || initialCap > maxCap {
return nil, ErrPoolInvalidCap
}
pool := &connPool{
conns: make(chan net.Conn, maxCap),
dialCtx: dialCtxFunc,
}
// create initial connections, if something goes wrong,
// just close the pool error out.
for i := 0; i < initialCap; i++ {
/*
conn, err := dialCtxFunc()
if err != nil {
pool.Close()
return nil, fmt.Errorf("factory is not able to fill the pool: %s", err)
}
c.conns <- conn
*/
}
return pool, nil
}
func (c *connPool) Get() (net.Conn, error) {
return nil, nil
}
func (c *connPool) Close() {
return
}
func (c *connPool) Len() int {
return 0
}