micro-client-grpc/grpc_pool.go

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2019-06-03 20:44:43 +03:00
package grpc
import (
"sync"
"time"
"google.golang.org/grpc"
)
type pool struct {
size int
ttl int64
sync.Mutex
conns map[string][]*poolConn
}
type poolConn struct {
*grpc.ClientConn
created int64
}
func newPool(size int, ttl time.Duration) *pool {
return &pool{
size: size,
ttl: int64(ttl.Seconds()),
conns: make(map[string][]*poolConn),
}
}
func (p *pool) getConn(addr string, opts ...grpc.DialOption) (*poolConn, error) {
p.Lock()
conns := p.conns[addr]
now := time.Now().Unix()
// while we have conns check age and then return one
// otherwise we'll create a new conn
for len(conns) > 0 {
conn := conns[len(conns)-1]
conns = conns[:len(conns)-1]
p.conns[addr] = conns
// if conn is old kill it and move on
if d := now - conn.created; d > p.ttl {
conn.ClientConn.Close()
continue
}
// we got a good conn, lets unlock and return it
p.Unlock()
return conn, nil
}
p.Unlock()
// create new conn
cc, err := grpc.Dial(addr, opts...)
if err != nil {
return nil, err
}
return &poolConn{cc, time.Now().Unix()}, nil
}
func (p *pool) release(addr string, conn *poolConn, err error) {
// don't store the conn if it has errored
if err != nil {
conn.ClientConn.Close()
return
}
// otherwise put it back for reuse
p.Lock()
conns := p.conns[addr]
if len(conns) >= p.size {
p.Unlock()
conn.ClientConn.Close()
return
}
p.conns[addr] = append(conns, conn)
p.Unlock()
}