migrated multi host connection pool from godropbox package

removing unneeded dependencies, which involved etcd versions.

weed/wdclient/net2/managed_connection.go

@@ -0,0 +1,185 @@
+package net2
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"errors"
+	"github.com/chrislusf/seaweedfs/weed/wdclient/resource_pool"
+)
+
+// Dial's arguments.
+type NetworkAddress struct {
+	Network string
+	Address string
+}
+
+// A connection managed by a connection pool.  NOTE: SetDeadline,
+// SetReadDeadline and SetWriteDeadline are disabled for managed connections.
+// (The deadlines are set by the connection pool).
+type ManagedConn interface {
+	net.Conn
+
+	// This returns the original (network, address) entry used for creating
+	// the connection.
+	Key() NetworkAddress
+
+	// This returns the underlying net.Conn implementation.
+	RawConn() net.Conn
+
+	// This returns the connection pool which owns this connection.
+	Owner() ConnectionPool
+
+	// This indictes a user is done with the connection and releases the
+	// connection back to the connection pool.
+	ReleaseConnection() error
+
+	// This indicates the connection is an invalid state, and that the
+	// connection should be discarded from the connection pool.
+	DiscardConnection() error
+}
+
+// A physical implementation of ManagedConn
+type managedConnImpl struct {
+	addr    NetworkAddress
+	handle  resource_pool.ManagedHandle
+	pool    ConnectionPool
+	options ConnectionOptions
+}
+
+// This creates a managed connection wrapper.
+func NewManagedConn(
+	network string,
+	address string,
+	handle resource_pool.ManagedHandle,
+	pool ConnectionPool,
+	options ConnectionOptions) ManagedConn {
+
+	addr := NetworkAddress{
+		Network: network,
+		Address: address,
+	}
+
+	return &managedConnImpl{
+		addr:    addr,
+		handle:  handle,
+		pool:    pool,
+		options: options,
+	}
+}
+
+func (c *managedConnImpl) rawConn() (net.Conn, error) {
+	h, err := c.handle.Handle()
+	return h.(net.Conn), err
+}
+
+// See ManagedConn for documentation.
+func (c *managedConnImpl) RawConn() net.Conn {
+	h, _ := c.handle.Handle()
+	return h.(net.Conn)
+}
+
+// See ManagedConn for documentation.
+func (c *managedConnImpl) Key() NetworkAddress {
+	return c.addr
+}
+
+// See ManagedConn for documentation.
+func (c *managedConnImpl) Owner() ConnectionPool {
+	return c.pool
+}
+
+// See ManagedConn for documentation.
+func (c *managedConnImpl) ReleaseConnection() error {
+	return c.handle.Release()
+}
+
+// See ManagedConn for documentation.
+func (c *managedConnImpl) DiscardConnection() error {
+	return c.handle.Discard()
+}
+
+// See net.Conn for documentation
+func (c *managedConnImpl) Read(b []byte) (n int, err error) {
+	conn, err := c.rawConn()
+	if err != nil {
+		return 0, err
+	}
+
+	if c.options.ReadTimeout > 0 {
+		deadline := c.options.getCurrentTime().Add(c.options.ReadTimeout)
+		_ = conn.SetReadDeadline(deadline)
+	}
+	n, err = conn.Read(b)
+	if err != nil {
+		var localAddr string
+		if conn.LocalAddr() != nil {
+			localAddr = conn.LocalAddr().String()
+		} else {
+			localAddr = "(nil)"
+		}
+
+		var remoteAddr string
+		if conn.RemoteAddr() != nil {
+			remoteAddr = conn.RemoteAddr().String()
+		} else {
+			remoteAddr = "(nil)"
+		}
+		err = fmt.Errorf("Read error from host: %s <-> %s: %v", localAddr, remoteAddr, err)
+	}
+	return
+}
+
+// See net.Conn for documentation
+func (c *managedConnImpl) Write(b []byte) (n int, err error) {
+	conn, err := c.rawConn()
+	if err != nil {
+		return 0, err
+	}
+
+	if c.options.WriteTimeout > 0 {
+		deadline := c.options.getCurrentTime().Add(c.options.WriteTimeout)
+		_ = conn.SetWriteDeadline(deadline)
+	}
+	n, err = conn.Write(b)
+	if err != nil {
+		err = fmt.Errorf("Write error: %v", err)
+	}
+	return
+}
+
+// See net.Conn for documentation
+func (c *managedConnImpl) Close() error {
+	return c.handle.Discard()
+}
+
+// See net.Conn for documentation
+func (c *managedConnImpl) LocalAddr() net.Addr {
+	conn, _ := c.rawConn()
+	return conn.LocalAddr()
+}
+
+// See net.Conn for documentation
+func (c *managedConnImpl) RemoteAddr() net.Addr {
+	conn, _ := c.rawConn()
+	return conn.RemoteAddr()
+}
+
+// SetDeadline is disabled for managed connection (The deadline is set by
+// us, with respect to the read/write timeouts specified in ConnectionOptions).
+func (c *managedConnImpl) SetDeadline(t time.Time) error {
+	return errors.New("Cannot set deadline for managed connection")
+}
+
+// SetReadDeadline is disabled for managed connection (The deadline is set by
+// us with respect to the read timeout specified in ConnectionOptions).
+func (c *managedConnImpl) SetReadDeadline(t time.Time) error {
+	return errors.New("Cannot set read deadline for managed connection")
+}
+
+// SetWriteDeadline is disabled for managed connection (The deadline is set by
+// us with respect to the write timeout specified in ConnectionOptions).
+func (c *managedConnImpl) SetWriteDeadline(t time.Time) error {
+	return errors.New("Cannot set write deadline for managed connection")
+}