tailscale/cmd/tsconnect/common.go
Mihai Parparita 6f5096fa61 cmd/tsconnect: initial scaffolding for Tailscale Connect browser client
Runs a Tailscale client in the browser (via a WebAssembly build of the
wasm package) and allows SSH access to machines. The wasm package exports
a newIPN function, which returns a simple JS object with methods like
start(), login(), logout() and ssh(). The golang.org/x/crypto/ssh
package is used for the SSH client.

Terminal emulation and QR code renedring is done via NPM packages (xterm
and qrcode respectively), thus we also need a JS toolchain that can
install and bundle them. Yarn is used for installation, and esbuild
handles loading them and bundling for production serving.

Updates #3157

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
2022-07-19 13:43:08 -07:00

106 lines
3.1 KiB
Go

// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"log"
"os"
"os/exec"
"path"
"path/filepath"
"runtime"
"strconv"
esbuild "github.com/evanw/esbuild/pkg/api"
)
const (
devMode = true
prodMode = false
)
// commonSetup performs setup that is common to both dev and build modes.
func commonSetup(dev bool) (*esbuild.BuildOptions, error) {
// Change cwd to to where this file lives -- that's where all inputs for
// esbuild and other build steps live.
if _, filename, _, ok := runtime.Caller(0); ok {
if err := os.Chdir(path.Dir(filename)); err != nil {
return nil, fmt.Errorf("Cannot change cwd: %w", err)
}
}
if err := buildDeps(dev); err != nil {
return nil, fmt.Errorf("Cannot build deps: %w", err)
}
return &esbuild.BuildOptions{
EntryPoints: []string{"src/index.js", "src/index.css"},
Loader: map[string]esbuild.Loader{".wasm": esbuild.LoaderFile},
Outdir: "./dist",
Bundle: true,
Sourcemap: esbuild.SourceMapLinked,
LogLevel: esbuild.LogLevelInfo,
Define: map[string]string{"DEBUG": strconv.FormatBool(dev)},
Target: esbuild.ES2017,
}, nil
}
// buildDeps builds the static assets that are needed for the server (except for
// JS/CSS bundling, which is handled by esbuild).
func buildDeps(dev bool) error {
if err := copyWasmExec(); err != nil {
return fmt.Errorf("Cannot copy wasm_exec.js: %w", err)
}
if err := buildWasm(dev); err != nil {
return fmt.Errorf("Cannot build main.wasm: %w", err)
}
if err := installJSDeps(); err != nil {
return fmt.Errorf("Cannot install JS deps: %w", err)
}
return nil
}
// copyWasmExec grabs the current wasm_exec.js runtime helper library from the
// Go toolchain.
func copyWasmExec() error {
log.Printf("Copying wasm_exec.js...\n")
wasmExecSrcPath := filepath.Join(runtime.GOROOT(), "misc", "wasm", "wasm_exec.js")
wasmExecDstPath := filepath.Join("src", "wasm_exec.js")
contents, err := os.ReadFile(wasmExecSrcPath)
if err != nil {
return err
}
return os.WriteFile(wasmExecDstPath, contents, 0600)
}
// buildWasm builds the Tailscale wasm binary and places it where the JS can
// load it.
func buildWasm(dev bool) error {
log.Printf("Building wasm...\n")
args := []string{"build", "-tags", "tailscale_go,osusergo,netgo,nethttpomithttp2,omitidna,omitpemdecrypt"}
if !dev {
// Omit long paths and debug symbols in release builds, to reduce the
// generated WASM binary size.
args = append(args, "-trimpath", "-ldflags", "-s -w")
}
args = append(args, "-o", "src/main.wasm", "./wasm")
cmd := exec.Command(filepath.Join(runtime.GOROOT(), "bin", "go"), args...)
cmd.Env = append(os.Environ(), "GOOS=js", "GOARCH=wasm")
cmd.Stdin = os.Stdin
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
return cmd.Run()
}
// installJSDeps installs the JavaScript dependencies specified by package.json
func installJSDeps() error {
log.Printf("Installing JS deps...\n")
stdoutStderr, err := exec.Command("yarn").CombinedOutput()
if err != nil {
log.Printf("yarn failed: %s", stdoutStderr)
}
return err
}