mtsatellite/main.go

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2014-08-03 00:01:14 +02:00
package main
import (
"bufio"
"flag"
"fmt"
"log"
"net"
"os"
"os/signal"
leveldb "github.com/jmhodges/levigo"
)
type connection struct {
conn net.Conn
db *leveldb.DB
tx *leveldb.WriteBatch
intArray []int
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}
func newConnection(conn net.Conn, db *leveldb.DB) *connection {
return &connection{
conn,
db,
nil,
[]int{}}
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}
func (c *connection) run() {
defer c.conn.Close()
rce := NewRedisCommandExecutor(c)
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r := bufio.NewReader(c.conn)
parser := NewRedisParser(r, rce)
parser.Parse()
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}
func (c *connection) Hget(hash, key []byte) bool {
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log.Printf("client requested block: %q", key)
var err error
var data []byte
ro := leveldb.NewReadOptions()
defer ro.Close()
if data, err = c.db.Get(ro, key); err != nil {
log.Printf("Something is wrong with db: %s", err)
if err = c.writeError(); err != nil {
log.Printf("Send message to client failed: %s", err)
return false
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}
} else {
if err = c.writeBlock(data); err != nil {
log.Printf("Send message to client failed: %s", err)
return false
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}
}
return true
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}
func (c *connection) Hset(hash, key, block []byte) bool {
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log.Printf("client wants to store block: %q", key)
var err error
var exists int
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if exists, err = c.keyExists(key); err != nil {
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log.Printf("Something is wrong with db: %s", err)
if err = c.writeError(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
}
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if c.tx != nil {
c.tx.Put(key, block)
c.intArray = append(c.intArray, exists)
if err = c.writeQueued(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
}
wo := leveldb.NewWriteOptions()
defer wo.Close()
if err = c.db.Put(wo, key, block); err != nil {
log.Printf("Something is wrong with db: %s", err)
if err = c.writeError(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
}
if err = c.writeInteger(exists); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
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}
func (c *connection) keyExists(key []byte) (exists int, err error) {
ro := leveldb.NewReadOptions()
defer ro.Close()
var data []byte
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if data, err = c.db.Get(ro, key); err != nil {
return
}
if data != nil {
exists = 1
} else {
exists = 0
}
return
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}
func (c *connection) Multi() bool {
if c.tx != nil {
log.Println("WARN: Already running transaction.")
} else {
c.tx = leveldb.NewWriteBatch()
}
if err := c.writeOk(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
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}
func (c *connection) Exec() bool {
var err error
if c.tx == nil {
if err = c.writeEmptyArray(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
}
tx := c.tx
c.tx = nil
defer tx.Close()
arr := c.intArray
c.intArray = []int{}
wo := leveldb.NewWriteOptions()
defer wo.Close()
if err = c.db.Write(wo, tx); err != nil {
log.Printf("Something went wrong in writing transaction: %s", err)
if err = c.writeError(); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
}
if err = c.writeIntegerArray(arr); err != nil {
log.Printf("Writing message to client failed: %s", err)
return false
}
return true
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}
var (
redisOk = []byte("+OK\r\n")
redisDbError = []byte("-FAIL\r\n")
redisNoSuchBlock = []byte("$-1\r\n")
redisCrnl = []byte("\r\n")
redisEmptyArray = []byte("*0\r\n")
redisQueued = []byte("+QUEUED\r\n")
)
func (c *connection) writeError() (err error) {
_, err = c.conn.Write(redisDbError)
return
}
func (c *connection) writeEmptyArray() (err error) {
_, err = c.conn.Write(redisDbError)
return
}
func (c *connection) writeInteger(v int) (err error) {
_, err = c.conn.Write([]byte(fmt.Sprintf(":%d\r\n", v)))
return
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}
func (c *connection) writeIntegerArray(arr []int) (err error) {
if _, err = c.conn.Write([]byte(fmt.Sprintf("*%d\r\n", len(arr)))); err != nil {
return
}
for x := range arr {
if err = c.writeInteger(x); err != nil {
return
}
}
return
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}
func (c *connection) writeOk() (err error) {
_, err = c.conn.Write(redisOk)
return
}
func (c *connection) writeQueued() (err error) {
_, err = c.conn.Write(redisQueued)
return
}
func (c *connection) writeBlock(data []byte) (err error) {
con := c.conn
if data == nil {
_, err = con.Write(redisNoSuchBlock)
} else {
if _, err = con.Write([]byte(fmt.Sprintf("$%d\r\n", len(data)))); err != nil {
return
}
if _, err = con.Write(data); err != nil {
return
}
_, err = con.Write(redisCrnl)
}
return
}
func main() {
var port int
var host string
var cacheSize int
flag.IntVar(&port, "port", 6379, "port to bind")
flag.StringVar(&host, "host", "", "host to bind")
flag.IntVar(&cacheSize, "cache", 32, "cache size in MB")
flag.Parse()
args := flag.Args()
if len(args) < 1 {
log.Fatal("Missing path to world")
}
cache := leveldb.NewLRUCache(cacheSize * 1024 * 1024)
defer cache.Close()
opts := leveldb.NewOptions()
opts.SetCache(cache)
opts.SetCreateIfMissing(true)
var err error
var db *leveldb.DB
if db, err = leveldb.Open(args[0], opts); err != nil {
log.Fatal(err)
}
defer db.Close()
var listener net.Listener
listener, err = net.Listen("tcp", fmt.Sprintf("%s:%d", host, port))
if err != nil {
log.Fatal(err)
}
defer listener.Close()
log.Printf("Server started at %s", listener.Addr())
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connChan := make(chan net.Conn)
defer close(connChan)
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, os.Interrupt, os.Kill)
go func() {
for {
conn, err := listener.Accept()
if err != nil {
log.Fatal(err)
}
log.Printf("Client accepted from: %s", conn.RemoteAddr())
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connChan <- conn
}
}()
for {
select {
case conn := <-connChan:
go newConnection(conn, db).run()
case <-sigChan:
log.Println("Shutting down")
return
}
}
}