feat: Add vscodeipc subcommand for VS Code Extension (#5326)

* Add extio

* feat: Add `vscodeipc` subcommand for VS Code Extension

This enables the VS Code extension to communicate with a Coder client.
The extension will download the slim binary from `/bin/*` for the
respective client architecture and OS, then execute `coder vscodeipc`
for the connecting workspace.

* Add authentication header, improve comments, and add tests for the CLI

* Update cli/vscodeipc_test.go

Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>

* Update cli/vscodeipc_test.go

Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>

* Update cli/vscodeipc/vscodeipc_test.go

Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>

* Fix requested changes

* Fix IPC tests

* Fix shell execution

* Fix nix flake

* Silence usage

Co-authored-by: Mathias Fredriksson <mafredri@gmail.com>

cli/vscodeipc/vscodeipc.go

@@ -0,0 +1,313 @@
+package vscodeipc
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/google/uuid"
+	"golang.org/x/crypto/ssh"
+	"golang.org/x/xerrors"
+	"tailscale.com/tailcfg"
+
+	"github.com/coder/coder/agent"
+	"github.com/coder/coder/coderd/httpapi"
+	"github.com/coder/coder/codersdk"
+)
+
+const AuthHeader = "Coder-IPC-Token"
+
+// New creates a VS Code IPC client that can be used to communicate with workspaces.
+//
+// Creating this IPC was required instead of using SSH, because we're unable to get
+// connection information to display in the bottom-bar when using SSH. It's possible
+// we could jank around this (maybe by using a temporary SSH host), but that's not
+// ideal.
+//
+// This persists a single workspace connection, and lets you execute commands, check
+// for network information, and forward ports.
+//
+// The VS Code extension is located at https://github.com/coder/vscode-coder. The
+// extension downloads the slim binary from `/bin/*` and executes `coder vscodeipc`
+// which calls this function. This API must maintain backward compatibility with
+// the extension to support prior versions of Coder.
+func New(ctx context.Context, client *codersdk.Client, agentID uuid.UUID, options *codersdk.DialWorkspaceAgentOptions) (http.Handler, io.Closer, error) {
+	if options == nil {
+		options = &codersdk.DialWorkspaceAgentOptions{}
+	}
+	// We need this to track upload and download!
+	options.EnableTrafficStats = true
+
+	agentConn, err := client.DialWorkspaceAgent(ctx, agentID, options)
+	if err != nil {
+		return nil, nil, err
+	}
+	api := &api{
+		agentConn: agentConn,
+	}
+	r := chi.NewRouter()
+	// This is to prevent unauthorized clients on the same machine from executing
+	// requests on behalf of the workspace.
+	r.Use(sessionTokenMiddleware(client.SessionToken()))
+	r.Route("/v1", func(r chi.Router) {
+		r.Get("/port/{port}", api.port)
+		r.Get("/network", api.network)
+		r.Post("/execute", api.execute)
+	})
+	return r, api, nil
+}
+
+type api struct {
+	agentConn     *codersdk.AgentConn
+	sshClient     *ssh.Client
+	sshClientErr  error
+	sshClientOnce sync.Once
+
+	lastNetwork time.Time
+}
+
+func (api *api) Close() error {
+	if api.sshClient != nil {
+		api.sshClient.Close()
+	}
+	return api.agentConn.Close()
+}
+
+type NetworkResponse struct {
+	P2P              bool               `json:"p2p"`
+	Latency          float64            `json:"latency"`
+	PreferredDERP    string             `json:"preferred_derp"`
+	DERPLatency      map[string]float64 `json:"derp_latency"`
+	UploadBytesSec   int64              `json:"upload_bytes_sec"`
+	DownloadBytesSec int64              `json:"download_bytes_sec"`
+}
+
+// port accepts an HTTP request to dial a port on the workspace agent.
+// It uses an HTTP connection upgrade to transfer the connection to TCP.
+func (api *api) port(w http.ResponseWriter, r *http.Request) {
+	port, err := strconv.Atoi(chi.URLParam(r, "port"))
+	if err != nil {
+		httpapi.Write(r.Context(), w, http.StatusBadRequest, codersdk.Response{
+			Message: "Port must be an integer!",
+		})
+		return
+	}
+	remoteConn, err := api.agentConn.DialContext(r.Context(), "tcp", fmt.Sprintf("127.0.0.1:%d", port))
+	if err != nil {
+		httpapi.InternalServerError(w, err)
+		return
+	}
+	defer remoteConn.Close()
+
+	// Upgrade an switch to TCP!
+	w.Header().Set("Connection", "Upgrade")
+	w.Header().Set("Upgrade", "tcp")
+	w.WriteHeader(http.StatusSwitchingProtocols)
+
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		httpapi.InternalServerError(w, xerrors.Errorf("unable to hijack connection: %T", w))
+		return
+	}
+
+	localConn, brw, err := hijacker.Hijack()
+	if err != nil {
+		httpapi.InternalServerError(w, err)
+		return
+	}
+	defer localConn.Close()
+
+	_ = brw.Flush()
+	agent.Bicopy(r.Context(), localConn, remoteConn)
+}
+
+// network returns network information about the workspace.
+func (api *api) network(w http.ResponseWriter, r *http.Request) {
+	// Ping the workspace agent to get the latency.
+	latency, p2p, err := api.agentConn.Ping(r.Context())
+	if err != nil {
+		httpapi.Write(r.Context(), w, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to ping the workspace agent.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	node := api.agentConn.Node()
+	derpMap := api.agentConn.DERPMap()
+	derpLatency := map[string]float64{}
+
+	// Convert DERP region IDs to friendly names for display in the UI.
+	for rawRegion, latency := range node.DERPLatency {
+		regionParts := strings.SplitN(rawRegion, "-", 2)
+		regionID, err := strconv.Atoi(regionParts[0])
+		if err != nil {
+			continue
+		}
+		region, found := derpMap.Regions[regionID]
+		if !found {
+			// It's possible that a workspace agent is using an old DERPMap
+			// and reports regions that do not exist. If that's the case,
+			// report the region as unknown!
+			region = &tailcfg.DERPRegion{
+				RegionID:   regionID,
+				RegionName: fmt.Sprintf("Unnamed %d", regionID),
+			}
+		}
+		// Convert the microseconds to milliseconds.
+		derpLatency[region.RegionName] = latency * 1000
+	}
+
+	totalRx := uint64(0)
+	totalTx := uint64(0)
+	for _, stat := range api.agentConn.ExtractTrafficStats() {
+		totalRx += stat.RxBytes
+		totalTx += stat.TxBytes
+	}
+	// Tracking the time since last request is required because
+	// ExtractTrafficStats() resets its counters after each call.
+	dur := time.Since(api.lastNetwork)
+	uploadSecs := float64(totalTx) / dur.Seconds()
+	downloadSecs := float64(totalRx) / dur.Seconds()
+
+	api.lastNetwork = time.Now()
+
+	httpapi.Write(r.Context(), w, http.StatusOK, NetworkResponse{
+		P2P:              p2p,
+		Latency:          float64(latency.Microseconds()) / 1000,
+		PreferredDERP:    derpMap.Regions[node.PreferredDERP].RegionName,
+		DERPLatency:      derpLatency,
+		UploadBytesSec:   int64(uploadSecs),
+		DownloadBytesSec: int64(downloadSecs),
+	})
+}
+
+type ExecuteRequest struct {
+	Command string `json:"command"`
+	Stdin   string `json:"stdin"`
+}
+
+type ExecuteResponse struct {
+	Data     string `json:"data"`
+	ExitCode *int   `json:"exit_code"`
+}
+
+// execute runs the command provided, streams the output back, and returns the exit code.
+func (api *api) execute(w http.ResponseWriter, r *http.Request) {
+	var req ExecuteRequest
+	if !httpapi.Read(r.Context(), w, r, &req) {
+		return
+	}
+	api.sshClientOnce.Do(func() {
+		// The SSH client is lazily created because it's not needed for
+		// all requests. It's only needed for the execute endpoint.
+		//
+		// It's alright if this fails on the first execution, because
+		// a new instance of this API is created for each remote SSH request.
+		api.sshClient, api.sshClientErr = api.agentConn.SSHClient(context.Background())
+	})
+	if api.sshClientErr != nil {
+		httpapi.Write(r.Context(), w, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to create SSH client.",
+			Detail:  api.sshClientErr.Error(),
+		})
+		return
+	}
+	session, err := api.sshClient.NewSession()
+	if err != nil {
+		httpapi.Write(r.Context(), w, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to create SSH session.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+	defer session.Close()
+	f, ok := w.(http.Flusher)
+	if !ok {
+		httpapi.Write(r.Context(), w, http.StatusInternalServerError, codersdk.Response{
+			Message: fmt.Sprintf("http.ResponseWriter is not http.Flusher: %T", w),
+		})
+		return
+	}
+
+	execWriter := &execWriter{w, f}
+	session.Stdout = execWriter
+	session.Stderr = execWriter
+	session.Stdin = strings.NewReader(req.Stdin)
+	err = session.Start(req.Command)
+	if err != nil {
+		httpapi.Write(r.Context(), w, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to start SSH session.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+	err = session.Wait()
+
+	writeExit := func(exitCode int) {
+		data, _ := json.Marshal(&ExecuteResponse{
+			ExitCode: &exitCode,
+		})
+		_, _ = w.Write(data)
+		f.Flush()
+	}
+
+	if err != nil {
+		var exitError *ssh.ExitError
+		if errors.As(err, &exitError) {
+			writeExit(exitError.ExitStatus())
+			return
+		}
+	}
+	writeExit(0)
+}
+
+type execWriter struct {
+	w http.ResponseWriter
+	f http.Flusher
+}
+
+func (e *execWriter) Write(data []byte) (int, error) {
+	js, err := json.Marshal(&ExecuteResponse{
+		Data: string(data),
+	})
+	if err != nil {
+		return 0, err
+	}
+	_, err = e.w.Write(js)
+	if err != nil {
+		return 0, err
+	}
+	e.f.Flush()
+	return len(data), nil
+}
+
+func sessionTokenMiddleware(sessionToken string) func(h http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			token := r.Header.Get(AuthHeader)
+			if token == "" {
+				httpapi.Write(r.Context(), w, http.StatusUnauthorized, codersdk.Response{
+					Message: fmt.Sprintf("A session token must be provided in the `%s` header.", AuthHeader),
+				})
+				return
+			}
+			if token != sessionToken {
+				httpapi.Write(r.Context(), w, http.StatusUnauthorized, codersdk.Response{
+					Message: "The session token provided doesn't match the one used to create the client.",
+				})
+				return
+			}
+			w.Header().Set("Access-Control-Allow-Origin", "*")
+			h.ServeHTTP(w, r)
+		})
+	}
+}

cli/vscodeipc/vscodeipc_test.go

@@ -0,0 +1,202 @@
+package vscodeipc_test
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"runtime"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/goleak"
+	"nhooyr.io/websocket"
+
+	"github.com/coder/coder/agent"
+	"github.com/coder/coder/cli/vscodeipc"
+	"github.com/coder/coder/coderd/httpapi"
+	"github.com/coder/coder/codersdk"
+	"github.com/coder/coder/tailnet"
+	"github.com/coder/coder/tailnet/tailnettest"
+	"github.com/coder/coder/testutil"
+)
+
+func TestMain(m *testing.M) {
+	goleak.VerifyTestMain(m)
+}
+
+func TestVSCodeIPC(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+
+	id := uuid.New()
+	derpMap := tailnettest.RunDERPAndSTUN(t)
+	coordinator := tailnet.NewCoordinator()
+	t.Cleanup(func() {
+		_ = coordinator.Close()
+	})
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch r.URL.Path {
+		case fmt.Sprintf("/api/v2/workspaceagents/%s/connection", id):
+			assert.Equal(t, r.Method, http.MethodGet)
+			httpapi.Write(ctx, w, http.StatusOK, codersdk.WorkspaceAgentConnectionInfo{
+				DERPMap: derpMap,
+			})
+			return
+		case fmt.Sprintf("/api/v2/workspaceagents/%s/coordinate", id):
+			assert.Equal(t, r.Method, http.MethodGet)
+			ws, err := websocket.Accept(w, r, nil)
+			require.NoError(t, err)
+			conn := websocket.NetConn(ctx, ws, websocket.MessageBinary)
+			_ = coordinator.ServeClient(conn, uuid.New(), id)
+			return
+		case "/api/v2/workspaceagents/me/version":
+			assert.Equal(t, r.Method, http.MethodPost)
+			w.WriteHeader(http.StatusOK)
+			return
+		case "/api/v2/workspaceagents/me/metadata":
+			assert.Equal(t, r.Method, http.MethodGet)
+			httpapi.Write(ctx, w, http.StatusOK, codersdk.WorkspaceAgentMetadata{
+				DERPMap: derpMap,
+			})
+			return
+		case "/api/v2/workspaceagents/me/coordinate":
+			assert.Equal(t, r.Method, http.MethodGet)
+			ws, err := websocket.Accept(w, r, nil)
+			require.NoError(t, err)
+			conn := websocket.NetConn(ctx, ws, websocket.MessageBinary)
+			_ = coordinator.ServeAgent(conn, id)
+			return
+		case "/api/v2/workspaceagents/me/report-stats":
+			assert.Equal(t, r.Method, http.MethodPost)
+			w.WriteHeader(http.StatusOK)
+			return
+		case "/":
+			w.WriteHeader(http.StatusOK)
+			return
+		default:
+			t.Fatalf("unexpected request %s", r.URL.Path)
+		}
+	}))
+	t.Cleanup(srv.Close)
+	srvURL, _ := url.Parse(srv.URL)
+
+	client := codersdk.New(srvURL)
+	token := uuid.New().String()
+	client.SetSessionToken(token)
+	agentConn := agent.New(agent.Options{
+		Client:     client,
+		Filesystem: afero.NewMemMapFs(),
+		TempDir:    t.TempDir(),
+	})
+	t.Cleanup(func() {
+		_ = agentConn.Close()
+	})
+
+	handler, closer, err := vscodeipc.New(ctx, client, id, nil)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = closer.Close()
+	})
+
+	// Ensure that we're actually connected!
+	require.Eventually(t, func() bool {
+		res := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/v1/network", nil)
+		req.Header.Set(vscodeipc.AuthHeader, token)
+		handler.ServeHTTP(res, req)
+		network := &vscodeipc.NetworkResponse{}
+		err = json.NewDecoder(res.Body).Decode(&network)
+		assert.NoError(t, err)
+		return network.Latency != 0
+	}, testutil.WaitLong, testutil.IntervalFast)
+
+	_, port, err := net.SplitHostPort(srvURL.Host)
+	require.NoError(t, err)
+
+	t.Run("NoSessionToken", func(t *testing.T) {
+		t.Parallel()
+		res := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, fmt.Sprintf("/v1/port/%s", port), nil)
+		handler.ServeHTTP(res, req)
+		require.Equal(t, http.StatusUnauthorized, res.Code)
+	})
+
+	t.Run("MismatchedSessionToken", func(t *testing.T) {
+		t.Parallel()
+		res := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, fmt.Sprintf("/v1/port/%s", port), nil)
+		req.Header.Set(vscodeipc.AuthHeader, uuid.NewString())
+		handler.ServeHTTP(res, req)
+		require.Equal(t, http.StatusUnauthorized, res.Code)
+	})
+
+	t.Run("Port", func(t *testing.T) {
+		// Tests that the port endpoint can be used for forward traffic.
+		// For this test, we simply use the already listening httptest server.
+		t.Parallel()
+		input, output := net.Pipe()
+		defer input.Close()
+		defer output.Close()
+		res := &hijackable{httptest.NewRecorder(), output}
+		req := httptest.NewRequest(http.MethodGet, fmt.Sprintf("/v1/port/%s", port), nil)
+		req.Header.Set(vscodeipc.AuthHeader, token)
+		go handler.ServeHTTP(res, req)
+
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, "http://127.0.0.1/", nil)
+		require.NoError(t, err)
+		client := http.Client{
+			Transport: &http.Transport{
+				DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+					return input, nil
+				},
+			},
+		}
+		resp, err := client.Do(req)
+		require.NoError(t, err)
+		defer resp.Body.Close()
+		require.Equal(t, http.StatusOK, resp.StatusCode)
+	})
+
+	t.Run("Execute", func(t *testing.T) {
+		t.Parallel()
+		if runtime.GOOS == "windows" {
+			t.Skip("Execute isn't supported on Windows yet!")
+			return
+		}
+
+		res := httptest.NewRecorder()
+		data, _ := json.Marshal(vscodeipc.ExecuteRequest{
+			Command: "echo test",
+		})
+		req := httptest.NewRequest(http.MethodPost, "/v1/execute", bytes.NewReader(data))
+		req.Header.Set(vscodeipc.AuthHeader, token)
+		handler.ServeHTTP(res, req)
+
+		decoder := json.NewDecoder(res.Body)
+		var msg vscodeipc.ExecuteResponse
+		err = decoder.Decode(&msg)
+		require.NoError(t, err)
+		require.Equal(t, "test\n", msg.Data)
+		err = decoder.Decode(&msg)
+		require.NoError(t, err)
+		require.Equal(t, 0, *msg.ExitCode)
+	})
+}
+
+type hijackable struct {
+	*httptest.ResponseRecorder
+	conn net.Conn
+}
+
+func (h *hijackable) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return h.conn, bufio.NewReadWriter(bufio.NewReader(h.conn), bufio.NewWriter(h.conn)), nil
+}