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move to using contexts to keep channels with connections

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This commit is contained in:
Sundog Jones 2021-04-14 14:58:02 -07:00
parent 30989fd935
commit 1f3c0331e7
2 changed files with 232 additions and 155 deletions
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353
main.go
View File

@ -1,6 +1,7 @@
package main
import (
"context"
"flag"
"log"
"net"
@ -10,8 +11,57 @@ import (
"time"
"github.com/xtaci/gaio"
"versestudios.com/go-telnet-asyncio-test/openconn"
)
type InChanKey string
type OutChanKey string
func ioHandler(w *gaio.Watcher, WatcherControl *chan string) {
for {
select {
case msg := <-*WatcherControl:
switch msg {
case "":
log.Println("empty WatcherControl command")
case "stop":
log.Println("stopping ioHandler via WatcherControl stop command")
return
default:
log.Println("unknown WatcherControl command:", msg)
}
default:
// loop wait for any IO events
results, err := w.WaitIO()
if err != nil {
log.Println(err)
return
}
IOLoop:
for _, res := range results {
if res.Context != nil && nil != res.Context.(context.Context) {
if inChan, _, ok := openconn.FromContext(res.Context.(context.Context)); ok {
switch res.Operation {
case gaio.OpRead: // read completion event
inChan <- res
// queue next read
w.Read(res.Context, res.Conn, nil)
default: // anything else (meaning write completions)
continue IOLoop
}
} else {
log.Printf("error getting inChan and outChan from context: %v\n", res.Context)
}
} else {
log.Printf("nil context! res: %v\n", res)
}
}
}
time.Sleep(time.Millisecond)
}
}
func main() {
port := flag.Int("port", 3333, "Port to accept connections on.")
host := flag.String("host", "127.0.0.1", "Host or IP to bind to")
@ -37,186 +87,173 @@ func main() {
}
log.Println("new client: ", conn.RemoteAddr())
// chan to terminate ioHandler when neccessary
WatcherControl := make(chan string)
// get new context with inChan and outChan for this client connection
ctx := openconn.NewContext(context.Background())
log.Printf("new context for client %v: %v\n", conn.RemoteAddr(), ctx)
// submit the first async write IO request
err = w.Write(nil, conn, welcomeHandler())
err = w.Write(ctx, conn, welcomeHandler())
if err != nil {
log.Printf("err sending welcomeHandler: %v\n", err)
return
}
// hand off channel to menuHandler
// menuHandler(w, conn)
wg := new(sync.WaitGroup)
// chan to terminate watcher goroutine when necessary
WatcherControl := make(chan string)
// watcher.WaitIO goroutine
wg.Add(1)
go func(WatcherControl *chan string) {
log.Println("starting menu watchercontrol")
defer wg.Done()
ControlLoop:
for {
log.Println("checking watcher waitio")
select {
case msg := <-*WatcherControl:
if msg == "stop" {
log.Println("closing menu watchercontrol")
break ControlLoop
}
default:
log.Println("menu watchercontrol waiting for IO")
inBuf := make([]byte, 256)
err := w.ReadTimeout(nil, conn, inBuf, time.Now().Add(time.Second))
// now that a prompt is (or will be) displayed, go ahead and listen for input
err = w.Read(ctx, conn, nil)
if err != nil {
log.Printf("err on watcher readtimeout in menu: %v\n", err)
continue
}
results, err := w.WaitIO()
if err != nil {
log.Println("watcher wait err: ", err)
continue
}
log.Println("menu received IO!")
for _, res := range results {
if res.Operation == gaio.OpRead && res.Size > 0 {
log.Println("menu receive: ", strings.TrimSpace(string(res.Buffer[:res.Size-2])))
switch string(strings.TrimSpace(string(res.Buffer[:res.Size-2]))) {
case "welcome":
if err := w.Write(nil, conn, welcomeHandler()); err != nil {
log.Printf("error sending welcomeHandler from cmd `welcome`: %v", err)
}
case "adventure":
// start the door and wait
log.Printf("starting door handler...")
/*
if err := doorHandler(&c); err != nil {
log.Printf("error from cmd `adventure`: %v", err)
}
log.Printf("returning from door")
n, err := c.Write([]byte("\n\n> "))
if err != nil {
log.Printf("error writing to connection: %v", err)
} else {
log.Printf("wrote %d byte prompt to connection", n)
}
*/
case "exit":
/*
if err := exitHandler(); err != nil {
log.Printf("error sending exitHandler from cmd `exit`: %v", err)
}
*/
default:
err := w.Write(nil, conn, []byte("huh?\n\n> "))
if err != nil {
log.Printf("error writing to connection: %v", err)
}
}
} else {
log.Println("watcher confirming write:", string(res.Buffer))
}
}
}
time.Sleep(time.Second)
}
log.Println("watcher controlloop closed!")
}(&WatcherControl)
log.Println("main thread waiting on wg")
wg.Wait()
log.Printf("Goodbye %s!", conn.RemoteAddr())
}
}
func menuHandler(w *gaio.Watcher, c net.Conn) {
wg := new(sync.WaitGroup)
// chan to terminate watcher goroutine when necessary
WatcherControl := make(chan string)
// watcher.WaitIO goroutine
wg.Add(1)
go func(WatcherControl *chan string) {
log.Println("starting menu watchercontrol")
defer wg.Done()
ControlLoop:
for {
log.Println("checking watcher waitio")
select {
case msg := <-*WatcherControl:
if msg == "stop" {
log.Println("closing menu watchercontrol")
break ControlLoop
}
default:
log.Println("menu watchercontrol waiting for IO")
results, err := w.WaitIO()
if err != nil {
log.Println(err)
log.Printf("err queueing w.Read: %v\n", err)
return
}
log.Println("menu received IO!")
for _, res := range results {
if res.Operation == gaio.OpRead {
log.Println("menu receive: ", string(res.Buffer))
switch string(res.Buffer) {
case "":
// noop
time.Sleep(time.Millisecond)
// menu handler for this connection
go menuHandler(ctx, conn, w)
// io handler for this connection
go ioHandler(w, &WatcherControl)
log.Println("main thread looping")
// wg.Wait()
// log.Printf("Goodbye %s!", conn.RemoteAddr())
}
}
func menuHandler(ctx context.Context, conn net.Conn, w *gaio.Watcher) {
var wg sync.WaitGroup
MenuControl := make(chan string)
var inChan, outChan chan gaio.OpResult
var ok bool
if inChan, outChan, ok = openconn.FromContext(ctx); !ok {
log.Println("Could not get inChan/outChan from context!", ok, ctx)
}
wg.Add(1)
go func(inChan, outChan chan gaio.OpResult, MenuControl chan string) {
defer wg.Done()
log.Println("starting menu loop")
paused := false
ControlLoop:
for {
// log.Println("checking watcher waitio")
select {
case msg := <-MenuControl:
log.Println("msg on MenuControl:", msg)
switch string(msg) {
case "stop":
log.Println("closing menu loop")
paused = true
break ControlLoop
case "pause":
log.Println("pausing menu loop via menucontrol")
paused = true
case "unpause":
log.Println("unpausing menu loop via menucontrol")
paused = false
default:
log.Println("menu received unknown command: ", msg)
}
default:
// log.Println("no msg on MenuControl, continuing")
if !paused {
// log.Println("menu watchercontrol waiting for IO")
select {
case res := <-inChan:
if res.Error != nil {
log.Println("error on inChan: ", res.Error)
}
if res.Operation == gaio.OpRead && res.Size > 0 && res.Conn == conn {
log.Printf("received on inChan: conn: %v, buffer size: %v\n", res.Conn.RemoteAddr(), res.Size)
log.Println("menu receive: ", strings.TrimSpace(string(res.Buffer[:res.Size-2])))
switch string(strings.TrimSpace(string(res.Buffer[:res.Size-2]))) {
case "welcome":
if err := w.Write(nil, c, welcomeHandler()); err != nil {
if err := w.Write(ctx, conn, welcomeHandler()); err != nil {
log.Printf("error sending welcomeHandler from cmd `welcome`: %v", err)
}
case "adventure":
// start the door and wait
log.Printf("starting door handler...")
/*
if err := doorHandler(&c); err != nil {
log.Printf("error from cmd `adventure`: %v", err)
}
log.Printf("starting simulated door handler...")
MenuControl <- "pause"
// if err := doorHandler(w); err != nil {
// log.Printf("error from cmd `adventure`: %v", err)
// }
time.Sleep(5 * time.Second)
log.Printf("returning from door")
n, err := c.Write([]byte("\n\n> "))
MenuControl <- "unpause"
err := w.Write(ctx, conn, []byte("\n\n> "))
if err != nil {
log.Printf("error writing to connection: %v", err)
} else {
log.Printf("wrote %d byte prompt to connection", n)
}
*/
case "exit":
/*
if err := exitHandler(); err != nil {
if err := w.Write(ctx, conn, exitHandler()); err != nil {
log.Printf("error sending exitHandler from cmd `exit`: %v", err)
} else {
// let's wait before we actually close the connection to try and ensure the write gets through
time.Sleep(time.Second)
log.Println("exiting...")
log.Printf("Goodbye %s!", conn.RemoteAddr())
err := w.Free(conn)
if err != nil {
log.Printf("err closing connection: %v\n", err)
}
MenuControl <- "stop"
break ControlLoop
}
default:
err := w.Write(ctx, conn, []byte("huh?\n\n> "))
if err != nil {
log.Printf("error writing to connection: %v", err)
}
}
} else {
// noop
log.Printf("received on inChan: conn: %v, buffer: %v\n", res.Conn.RemoteAddr(), string(res.Buffer))
}
/*
case res := <-outChan:
// log.Println("OpResult on outChan:", res)
if res.Error != nil {
log.Println("error on outChan: ", res.Error)
}
if res.Operation == gaio.OpWrite && res.Size > 0 && res.Conn == conn {
// write confirmation received
//log.Printf("received on outChan: conn: %v, buffer: %v\n", res.Conn.RemoteAddr(), string(res.Buffer))
} else {
// noop
log.Printf("watcher sent unknown on outChan: %v\n", res)
}
*/
default:
err := w.Write(nil, c, []byte("huh?\n\n> "))
if err != nil {
log.Printf("error writing to connection: %v", err)
// noop - wait a lil bit
time.Sleep(time.Millisecond)
}
}
} else {
log.Println("watcher confirming write:", string(res.Buffer))
if conn == nil {
log.Println("conn is nil!")
}
}
}
time.Sleep(time.Second)
}
log.Println("watcher controlloop closed!")
}(&WatcherControl)
log.Println("main thread waiting on wg")
wg.Wait()
log.Printf("Goodbye %s!", c.RemoteAddr())
time.Sleep(time.Millisecond)
}
log.Println("menu controlloop closed!")
}(inChan, outChan, MenuControl)
func sendClientText(w *gaio.Watcher, c net.Conn, s string) error {
err := w.Write(nil, c, []byte(s))
if err != nil {
log.Printf("error writing to connection: %v", err)
return err
}
return nil
log.Println("menu waiting on waitgroup")
wg.Wait()
log.Println("terminating menucontrol for client")
}
func welcomeHandler() []byte {
@ -247,10 +284,7 @@ func welcomeHandler() []byte {
return []byte(bannerText)
}
/*
func exitHandler(c net.Conn) error {
func exitHandler() []byte {
const exitMessage = "\x1b[2J\x1b[H\x1b[31m\x1b[J\r\n" + `
___| | |
@ -261,16 +295,13 @@ func exitHandler(c net.Conn) error {
`
err := sendClientText(c, exitMessage)
if err != nil {
log.Printf("error writing to connection: %v", err)
}
time.Sleep(500 * time.Millisecond)
return c.Close()
return []byte(exitMessage)
}
func doorHandler(c *net.Conn) error {
// rework to mimic mainHandler
/*
func doorHandler(w *gaio.Watcher) error {
const bannerText = "\r\nCOLOSSAL CAVE\r\n\r\n"
err := sendClientText(*c, bannerText)
if err != nil {

46
openconn/openconn.go Normal file
View File

@ -0,0 +1,46 @@
package openconn
import (
"context"
"github.com/xtaci/gaio"
)
// The key type is unexported to prevent collisions with context keys defined in
// other packages.
type key int
const inChanKey key = 0
const outChanKey key = 0
// NewContext returns a new Context carrying two new channels.
func NewContext(ctx context.Context) context.Context {
inChan := make(chan gaio.OpResult)
outChan := make(chan gaio.OpResult)
ctx = context.WithValue(ctx, inChanKey, inChan)
ctx = context.WithValue(ctx, outChanKey, outChan)
return ctx
}
// FromContext extracts the two channels from ctx, if present.
func FromContext(ctx context.Context) (chan gaio.OpResult, chan gaio.OpResult, bool) {
// ctx.Value returns nil if ctx has no value for the key;
// the type assertion returns ok=false for nil.
inChan, iok := ctx.Value(inChanKey).(chan gaio.OpResult)
outChan, ook := ctx.Value(outChanKey).(chan gaio.OpResult)
if iok && ook {
return inChan, outChan, iok && ook
}
return nil, nil, iok && ook
}
// FromOpResult extracts the two channels from a gaio.OpResult, if present.
func FromOpResult(res gaio.OpResult) (chan gaio.OpResult, chan gaio.OpResult, bool) {
ctx, ok := res.Context.(context.Context)
if ok {
inChan, iok := ctx.Value(inChanKey).(chan gaio.OpResult)
outChan, ook := ctx.Value(outChanKey).(chan gaio.OpResult)
return inChan, outChan, iok && ook
}
return nil, nil, ok
}