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vitess中rpc兼容http請求的技巧
vitess是google的一個mysql項目，用go和python實現。https://code.google.com/p/vitess/
vitess中用rpc方式來中轉mysql的請求，其中rpc的實現很有意思，兼容了http請求。
兼容http請求有明顯的好處：
1.可以用現成的監控工具來監控服務是否正常，不用另外寫插件
2.可以方便地實現查詢信息功能，不用另外再開發工具或者界麵
3.可以方便地用現成的工具測試
在vitess中很簡單地實現了這個功能。client在建立連接後，第一個包是http頭，而server端也會有一個200的回應。
詳細見代碼：
https://code.google.com/p/vitess/source/browse/py/net/gorpc.py#87
https://code.google.com/p/vitess/source/browse/go/rpcwrap/rpcwrap.go
python client：
class _GoRpcConn(object):
def __init__(self, timeout):
self.conn = None
self.timeout = timeout
self.start_time = None
def dial(self, uri):
parts = urlparse.urlparse(uri)
netloc = parts.netloc.split(':')
# NOTE(msolomon) since the deadlines are approximate in the code, set
# timeout to oversample to minimize waiting in the extreme failure mode.
socket_timeout = self.timeout / 10.0
self.conn = socket.create_connection((netloc[0], int(netloc[1])),
socket_timeout)
self.conn.sendall('CONNECT %s HTTP/1.0\n\n' % parts.path)
while True:
data = self.conn.recv(1024)
if not data:
raise GoRpcError('Unexpected EOF in handshake')
if '\n\n' in data:
return
go server：
const (
connected = "200 Connected to Go RPC"
)
type ClientCodecFactory func(conn io.ReadWriteCloser) rpc.ClientCodec
type BufferedConnection struct {
*bufio.Reader
io.WriteCloser
}
func NewBufferedConnection(conn io.ReadWriteCloser) *BufferedConnection {
return &BufferedConnection{bufio.NewReader(conn), conn}
}
// DialHTTP connects to a go HTTP RPC server using the specified codec.
func DialHTTP(network, address, codecName string, cFactory ClientCodecFactory) (*rpc.Client, error) {
var err error
conn, err := net.Dial(network, address)
if err != nil {
return nil, err
}
io.WriteString(conn, "CONNECT "+GetRpcPath(codecName)+" HTTP/1.0\n\n")
// Require successful HTTP response
// before switching to RPC protocol.
buffered := NewBufferedConnection(conn)
resp, err := http.ReadResponse(buffered.Reader, &http.Request{Method: "CONNECT"})
if err == nil && resp.Status == connected {
return rpc.NewClientWithCodec(cFactory(buffered)), nil
}
if err == nil {
err = errors.New("unexpected HTTP response: " + resp.Status)
}
conn.Close()
return nil, &net.OpError{"dial-http", network + " " + address, nil, err}
}
最後更新：2017-04-02 16:47:50