go language implementation of the memcache protocol service method
- 2020-05-30 20:19:55
- OfStack
This article illustrates an memcache protocol service implemented in the go language. Share with you for your reference. The details are as follows:
Click here to download the complete example code.
1. The Go language code is as follows:
package memcachep
import (
"bufio"
"fmt"
"io"
"strconv"
"strings"
)
//mc Request to produce 1 a request object
type MCRequest struct {
// Request command
Opcode CommandCode
//key
Key string
// Request content
Value []byte
// The request id
Flags int
// Request content length
Length int
// Expiration time
Expires int64
}
//request to string
func (req *MCRequest) String() string {
return fmt.Sprintf("{MCRequest opcode=%s, bodylen=%d, key='%s'}",
req.Opcode, len(req.Value), req.Key)
}
// will socket Request content Resolve to 1 a MCRequest object
func (req *MCRequest) Receive(r *bufio.Reader) error {
line, _, err := r.ReadLine()
if err != nil || len(line) == 0 {
return io.EOF
}
params := strings.Fields(string(line))
command := CommandCode(params[0])
switch command {
case SET, ADD, REPLACE:
req.Opcode = command
req.Key = params[1]
req.Length, _ = strconv.Atoi(params[4])
value := make([]byte, req.Length+2)
io.ReadFull(r, value)
req.Value = make([]byte, req.Length)
copy(req.Value, value)
case GET:
req.Opcode = command
req.Key = params[1]
RunStats["cmd_get"].(*CounterStat).Increment(1)
case STATS:
req.Opcode = command
req.Key = ""
case DELETE:
req.Opcode = command
req.Key = params[1]
}
return err
}
2. Go language code:
package memcachep
import (
"fmt"
"io"
)
type MCResponse struct {
// The command
Opcoed CommandCode
// Return status
Status Status
//key
Key string
// Returns the content
Value []byte
// Return to identify
Flags int
// error
Fatal bool
}
// parsing response And write the return result socket link
func (res *MCResponse) Transmit(w io.Writer) (err error) {
switch res.Opcoed {
case STATS:
_, err = w.Write(res.Value)
case GET:
if res.Status == SUCCESS {
rs := fmt.Sprintf("VALUE %s %d %d\r\n%s\r\nEND\r\n", res.Key, res.Flags, len(res.Value), res.Value)
_, err = w.Write([]byte(rs))
} else {
_, err = w.Write([]byte(res.Status.ToString()))
}
case SET, REPLACE:
_, err = w.Write([]byte(res.Status.ToString()))
case DELETE:
_, err = w.Write([]byte("DELETED\r\n"))
}
return
}
3. The Go language code is as follows:
package memcachep
import (
"fmt"
)
type action func(req *MCRequest, res *MCResponse)
var actions = map[CommandCode]action{
STATS: StatsAction,
}
// Waiting for distribution
func waitDispatch(rc chan chanReq) {
for {
input := <-rc
input.response <- dispatch(input.request)
}
}
// Distribute the request to the response action Operation function up
func dispatch(req *MCRequest) (res *MCResponse) {
if h, ok := actions[req.Opcode]; ok {
res = &MCResponse{}
h(req, res)
} else {
return notFound(req)
}
return
}
// Unsupported command
func notFound(req *MCRequest) *MCResponse {
var response MCResponse
response.Status = UNKNOWN_COMMAND
return &response
}
// to request Bind to the handler
func BindAction(opcode CommandCode, h action) {
actions[opcode] = h
}
//stats
func StatsAction(req *MCRequest, res *MCResponse) {
res.Fatal = false
stats := ""
for key, value := range RunStats {
stats += fmt.Sprintf("STAT %s %s\r\n", key, value)
}
stats += "END\r\n"
res.Value = []byte(stats)
}
I hope this article has helped you with your Go language programming.