Add reconnecting ptys (#23)

* Add pty reconnections

* Add reconnection to dev client

* Add reconnect tests

* Update go get to go install

This is failing CI.

Author: code-asher

Diff for: README.md

@@ -4,7 +4,7 @@
 <strong style="font-size: 1.5em; text-decoration: underline;">w</strong>eb <strong style="font-size: 1.5em;text-decoration: underline;">s</strong>ocket command <strong style="font-size: 1.5em;text-decoration: underline;">e</strong>xecution <strong style="font-size: 1.5em;text-decoration: underline;">p</strong>rotocol. It can be thought of as SSH without encryption.
 
 It's useful in cases where you want to provide a command exec interface into a remote environment. It's implemented
-with WebSocket so it may be used directly by a browser frontend. Its symmetric design satisfies 
+with WebSocket so it may be used directly by a browser frontend. Its symmetric design satisfies
 `wsep.Execer` for local and remote execution.
 
 ## Examples
@@ -54,19 +54,19 @@ go run ./dev/server
 Start a client:
 
 ```sh
-go run ./dev/client tty bash
-go run ./dev/client notty ls
+go run ./dev/client tty --id 1 -- bash
+go run ./dev/client notty -- ls -la
 ```
 
 ### Local performance cost
 
 Local `sh` through a local `wsep` connection
 
 ```shell script
-$ head -c 100000000 /dev/urandom > /tmp/random; cat /tmp/random | pv | time ./bin/client notty sh -c "cat > /dev/null"
+$ head -c 100000000 /dev/urandom > /tmp/random; cat /tmp/random | pv | time ./bin/client notty -- sh -c "cat > /dev/null"
 
 95.4MiB 0:00:00 [ 269MiB/s] [ <=>                                                                                  ]
-./bin/client notty sh -c "cat > /dev/null"  0.32s user 0.31s system 31% cpu 2.019 total
+./bin/client notty -- sh -c "cat > /dev/null"  0.32s user 0.31s system 31% cpu 2.019 total
 ```
 
 Local `sh` directly

Diff for: ci/image/Dockerfile

@@ -3,6 +3,6 @@ FROM golang:1
 ENV GOFLAGS="-mod=readonly"
 ENV CI=true
 
-RUN go get golang.org/x/tools/cmd/goimports
-RUN go get golang.org/x/lint/golint
-RUN go get github.com/mattn/goveralls
+RUN go install golang.org/x/tools/cmd/goimports@latest
+RUN go install golang.org/x/lint/golint@latest
+RUN go install github.com/mattn/goveralls@latest

Diff for: client.go

@@ -27,6 +27,8 @@ func RemoteExecer(conn *websocket.Conn) Execer {
 
 // Command represents an external command to be run
 type Command struct {
+	// ID allows reconnecting commands that have a TTY.
+	ID         string
 	Command    string
 	Args       []string
 	TTY        bool
@@ -39,6 +41,7 @@ type Command struct {
 
 func (r remoteExec) Start(ctx context.Context, c Command) (Process, error) {
 	header := proto.ClientStartHeader{
+		ID:      c.ID,
 		Command: mapToProtoCmd(c),
 		Type:    proto.TypeStart,
 	}

Diff for: client_test.go

@@ -49,14 +49,14 @@ func TestRemoteStdin(t *testing.T) {
 	}
 }
 
-func mockConn(ctx context.Context, t *testing.T) (*websocket.Conn, *httptest.Server) {
+func mockConn(ctx context.Context, t *testing.T, options *Options) (*websocket.Conn, *httptest.Server) {
 	mockServerHandler := func(w http.ResponseWriter, r *http.Request) {
 		ws, err := websocket.Accept(w, r, nil)
 		if err != nil {
 			w.WriteHeader(http.StatusInternalServerError)
 			return
 		}
-		err = Serve(r.Context(), ws, LocalExecer{})
+		err = Serve(r.Context(), ws, LocalExecer{}, options)
 		if err != nil {
 			t.Errorf("failed to serve execer: %v", err)
 			ws.Close(websocket.StatusAbnormalClosure, "failed to serve execer")
@@ -77,7 +77,7 @@ func TestRemoteExec(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
 	defer cancel()
 
-	ws, server := mockConn(ctx, t)
+	ws, server := mockConn(ctx, t, nil)
 	defer server.Close()
 
 	execer := RemoteExecer(ws)
@@ -89,7 +89,7 @@ func TestRemoteExecFail(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
 	defer cancel()
 
-	ws, server := mockConn(ctx, t)
+	ws, server := mockConn(ctx, t, nil)
 	defer server.Close()
 
 	execer := RemoteExecer(ws)
@@ -123,7 +123,7 @@ func TestStderrVsStdout(t *testing.T) {
 		stderr bytes.Buffer
 	)
 
-	ws, server := mockConn(ctx, t)
+	ws, server := mockConn(ctx, t, nil)
 	defer server.Close()
 
 	execer := RemoteExecer(ws)

Diff for: dev/client/main.go

@@ -23,35 +23,38 @@ type notty struct {
 }
 
 func (c *notty) Run(fl *pflag.FlagSet) {
-	do(fl, false)
+	do(fl, false, "")
 }
 
 func (c *notty) Spec() cli.CommandSpec {
 	return cli.CommandSpec{
-		Name:    "notty",
-		Usage:   "[flags]",
-		Desc:    `Run a command without tty enabled.`,
-		RawArgs: true,
+		Name:  "notty",
+		Usage: "[flags]",
+		Desc:  `Run a command without tty enabled.`,
 	}
 }
 
 type tty struct {
+	id string
 }
 
 func (c *tty) Run(fl *pflag.FlagSet) {
-	do(fl, true)
+	do(fl, true, c.id)
 }
 
 func (c *tty) Spec() cli.CommandSpec {
 	return cli.CommandSpec{
-		Name:    "tty",
-		Usage:   "[flags]",
-		Desc:    `Run a command with tty enabled.`,
-		RawArgs: true,
+		Name:  "tty",
+		Usage: "[id] [flags]",
+		Desc:  `Run a command with tty enabled.  Use the same ID to reconnect.`,
 	}
 }
 
-func do(fl *pflag.FlagSet, tty bool) {
+func (c *tty) RegisterFlags(fl *pflag.FlagSet) {
+	fl.StringVar(&c.id, "id", "", "sets id for reconnection")
+}
+
+func do(fl *pflag.FlagSet, tty bool, id string) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -71,6 +74,7 @@ func do(fl *pflag.FlagSet, tty bool) {
 		args = fl.Args()[1:]
 	}
 	process, err := executor.Start(ctx, wsep.Command{
+		ID:      id,
 		Command: fl.Arg(0),
 		Args:    args,
 		TTY:     tty,

Diff for: dev/server/main.go

@@ -23,7 +23,7 @@ func serve(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
-	err = wsep.Serve(r.Context(), ws, wsep.LocalExecer{})
+	err = wsep.Serve(r.Context(), ws, wsep.LocalExecer{}, nil)
 	if err != nil {
 		flog.Error("failed to serve execer: %v", err)
 		ws.Close(websocket.StatusAbnormalClosure, "failed to serve execer")

Diff for: go.mod

@@ -4,8 +4,10 @@ go 1.14
 
 require (
 	cdr.dev/slog v1.3.0
+	github.com/armon/circbuf v0.0.0-20190214190532-5111143e8da2
 	github.com/creack/pty v1.1.11
 	github.com/google/go-cmp v0.4.0
+	github.com/google/uuid v1.3.0
 	github.com/spf13/pflag v1.0.5
 	go.coder.com/cli v0.4.0
 	go.coder.com/flog v0.0.0-20190906214207-47dd47ea0512

Diff for: go.sum

@@ -30,6 +30,8 @@ github.com/alecthomas/kong v0.2.1-0.20190708041108-0548c6b1afae/go.mod h1:+inYUS
 github.com/alecthomas/kong-hcl v0.1.8-0.20190615233001-b21fea9723c8/go.mod h1:MRgZdU3vrFd05IQ89AxUZ0aYdF39BYoNFa324SodPCA=
 github.com/alecthomas/repr v0.0.0-20180818092828-117648cd9897 h1:p9Sln00KOTlrYkxI1zYWl1QLnEqAqEARBEYa8FQnQcY=
 github.com/alecthomas/repr v0.0.0-20180818092828-117648cd9897/go.mod h1:xTS7Pm1pD1mvyM075QCDSRqH6qRLXylzS24ZTpRiSzQ=
+github.com/armon/circbuf v0.0.0-20190214190532-5111143e8da2 h1:7Ip0wMmLHLRJdrloDxZfhMm0xrLXZS8+COSu2bXmEQs=
+github.com/armon/circbuf v0.0.0-20190214190532-5111143e8da2/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
 github.com/creack/pty v1.1.11 h1:07n33Z8lZxZ2qwegKbObQohDhXDQxiMMz1NOUGYlesw=
@@ -92,6 +94,8 @@ github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXi
 github.com/google/pprof v0.0.0-20181206194817-3ea8567a2e57/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
 github.com/google/pprof v0.0.0-20190515194954-54271f7e092f/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
+github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
+github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
 github.com/gorilla/csrf v1.6.0/go.mod h1:7tSf8kmjNYr7IWDCYhd3U8Ck34iQ/Yw5CJu7bAkHEGI=

Diff for: internal/proto/clientmsg.go

@@ -18,6 +18,7 @@ type ClientResizeHeader struct {
 // ClientStartHeader specifies a request to start command
 type ClientStartHeader struct {
 	Type    string  `json:"type"`
+	ID      string  `json:"id"`
 	Command Command `json:"command"`
 }