Files
red-apter/src/adapt.go
2026-02-04 08:48:53 -07:00

150 lines
3.2 KiB
Go
Executable File

package src
import (
"bufio"
"bytes"
"context"
"fmt"
"io"
"log"
"net"
"strconv"
)
func adapt(ctx context.Context, config Config, conn net.Conn) error {
reader := bufio.NewReader(conn)
for ctx.Err() == nil {
if done, err := func() (bool, error) {
raw, message, err := readMessage(reader)
if err != nil {
if err == io.EOF {
return true, nil
}
return true, err
}
log.Printf("routing: %q (%+v)", raw, message)
if len(message) > 0 && message[0].(string) == "COMMAND" {
fmt.Fprintf(conn, "*0\r\n")
} else if len(raw) > 0 && len(message) > 0 {
hashKey := message[0].(string)
if len(message) > 1 {
hashKey = message[1].(string)
}
if err := config.WithConn(hashKey, func(forwardConn net.Conn) error {
//log.Printf("forwarding %q", raw)
written := 0
for written < len(raw) {
more, err := forwardConn.Write(raw[written:])
if err != nil {
return err
}
written += more
}
replyer := bufio.NewReader(forwardConn)
//log.Printf("reading reply to %q", raw)
_, err = readMessageTo(conn, replyer)
//log.Printf("read reply %q", raw)
return err
}); err != nil {
return true, err
}
}
return false, nil
}(); err != nil {
return err
} else if done {
return nil
}
}
return io.EOF
}
func readMessage(reader *bufio.Reader) ([]byte, error) {
w := bytes.NewBuffer(nil)
err := readMessageTo(w, reader)
return w.Bytes(), err
}
func readMessageTo(w io.Writer, reader *bufio.Reader) error {
w2 := bufio.NewWriter(w)
defer w2.Flush()
err := _readMessageTo(w2, reader)
if err != nil {
return err
}
return w2.Flush()
}
func _readMessageTo(w io.Writer, reader *bufio.Reader) error {
firstLine, _, err := reader.ReadLine()
if err != nil {
return err
}
firstLine = bytes.TrimSuffix(firstLine, []byte("\r\n"))
if len(firstLine) == 0 {
return nil
}
fmt.Fprintf(w, "%s\r\n", firstLine)
switch firstLine[0] {
case '+': // simple string, like +OK
return nil
case '-': // simple error, like -message
return nil
case ':': // number, like /[+-][0-9]+/
return err
case '$': // long string, like $-1 for nil, like $LEN\r\nSTRING\r\n
if firstLine[1] == '-' {
return nil
}
firstLine = bytes.TrimPrefix(firstLine[1:], []byte("+"))
n, err := strconv.Atoi(string(firstLine))
if err != nil {
return fmt.Errorf("num not a num: %q: %w", firstLine, err)
}
nextLine := make([]byte, n+2)
nAt := 0
for nAt < n+2 {
nMore, err := reader.Read(nextLine[nAt:])
if err != nil {
return fmt.Errorf("couldnt read %v more/%v bytes for long string: %w", n+2-nAt, n+2, err)
}
nAt += nMore
}
fmt.Fprintf(w, "%s", nextLine)
return err
case '*', '%': // *=array %=map, like *-1 for nil, like *4 for [1,2,3,4]
n, err := strconv.Atoi(string(firstLine[1:]))
if err != nil {
return fmt.Errorf("arr not a num: %q: %w", firstLine, err)
} else if n == -1 {
return nil
}
if firstLine[0] == '%' {
n *= 2
}
for i := 0; i < n; i++ {
err := _readMessageTo(w, reader)
if err != nil {
return err
}
}
return nil
case '_': // nil
return nil
case '#': // boolean, like #t or #f
return nil
case ',': // double
return nil
}
log.Fatalf("not impl: %q", firstLine)
return nil
}