testing: add start of an integration test

Only minimal tailscale + tailscaled for now.

And a super minimal in-memory logcatcher.

No control ... yet.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tstest/integration/integration_test.go

@@ -0,0 +1,175 @@
+// Copyright (c) 2021 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 integration contains Tailscale integration tests.
+package integration
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"go4.org/mem"
+	"tailscale.com/smallzstd"
+	"tailscale.com/tstest"
+)
+
+func TestIntegration(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("not tested/working on Windows yet")
+	}
+	td := t.TempDir()
+	daemonExe := build(t, td, "tailscale.com/cmd/tailscaled")
+	cliExe := build(t, td, "tailscale.com/cmd/tailscale")
+
+	logc := new(logCatcher)
+	ts := httptest.NewServer(logc)
+	defer ts.Close()
+
+	socketPath := filepath.Join(td, "tailscale.sock")
+	dcmd := exec.Command(daemonExe,
+		"--tun=userspace-networking",
+		"--state="+filepath.Join(td, "tailscale.state"),
+		"--socket="+socketPath,
+	)
+	dcmd.Env = append(os.Environ(), "TS_LOG_TARGET="+ts.URL)
+	if err := dcmd.Start(); err != nil {
+		t.Fatalf("starting tailscaled: %v", err)
+	}
+	defer dcmd.Process.Kill()
+
+	var json []byte
+	if err := tstest.WaitFor(20*time.Second, func() (err error) {
+		json, err = exec.Command(cliExe, "--socket="+socketPath, "status", "--json").CombinedOutput()
+		if err != nil {
+			return fmt.Errorf("running tailscale status: %v, %s", err, json)
+		}
+		return nil
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	if err := tstest.WaitFor(20*time.Second, func() error {
+		const sub = `Program starting: `
+		if !logc.logsContains(mem.S(sub)) {
+			return fmt.Errorf("log catcher didn't see %#q; got %s", sub, logc.logsString())
+		}
+		return nil
+	}); err != nil {
+		t.Error(err)
+	}
+
+	dcmd.Process.Signal(os.Interrupt)
+
+	ps, err := dcmd.Process.Wait()
+	if err != nil {
+		t.Fatalf("tailscaled Wait: %v", err)
+	}
+	if ps.ExitCode() != 0 {
+		t.Errorf("tailscaled ExitCode = %d; want 0", ps.ExitCode())
+	}
+
+	t.Logf("number of HTTP logcatcher requests: %v", logc.numRequests())
+}
+
+func build(t *testing.T, outDir, target string) string {
+	exe := ""
+	if runtime.GOOS == "windows" {
+		exe = ".exe"
+	}
+	bin := filepath.Join(outDir, path.Base(target)) + exe
+	errOut, err := exec.Command("go", "build", "-o", bin, target).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to build %v: %v, %s", target, err, errOut)
+	}
+	return bin
+}
+
+type logCatcher struct {
+	mu     sync.Mutex
+	buf    bytes.Buffer
+	gotErr error
+	reqs   int
+}
+
+func (lc *logCatcher) logsContains(sub mem.RO) bool {
+	lc.mu.Lock()
+	defer lc.mu.Unlock()
+	return mem.Contains(mem.B(lc.buf.Bytes()), sub)
+}
+
+func (lc *logCatcher) numRequests() int {
+	lc.mu.Lock()
+	defer lc.mu.Unlock()
+	return lc.reqs
+}
+
+func (lc *logCatcher) logsString() string {
+	lc.mu.Lock()
+	defer lc.mu.Unlock()
+	return lc.buf.String()
+}
+
+func (lc *logCatcher) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var body io.Reader = r.Body
+	if r.Header.Get("Content-Encoding") == "zstd" {
+		var err error
+		body, err = smallzstd.NewDecoder(body)
+		if err != nil {
+			log.Printf("bad caught zstd: %v", err)
+			http.Error(w, err.Error(), 400)
+			return
+		}
+	}
+	bodyBytes, _ := ioutil.ReadAll(body)
+
+	type Entry struct {
+		Logtail struct {
+			ClientTime time.Time `json:"client_time"`
+			ServerTime time.Time `json:"server_time"`
+			Error      struct {
+				BadData string `json:"bad_data"`
+			} `json:"error"`
+		} `json:"logtail"`
+		Text string `json:"text"`
+	}
+	var jreq []Entry
+	var err error
+	if len(bodyBytes) > 0 && bodyBytes[0] == '[' {
+		err = json.Unmarshal(bodyBytes, &jreq)
+	} else {
+		var ent Entry
+		err = json.Unmarshal(bodyBytes, &ent)
+		jreq = append(jreq, ent)
+	}
+
+	lc.mu.Lock()
+	defer lc.mu.Unlock()
+	lc.reqs++
+	if lc.gotErr == nil && err != nil {
+		lc.gotErr = err
+	}
+	if err != nil {
+		fmt.Fprintf(&lc.buf, "error from %s of %#q: %v\n", r.Method, bodyBytes, err)
+	} else {
+		for _, ent := range jreq {
+			fmt.Fprintf(&lc.buf, "%s\n", strings.TrimSpace(ent.Text))
+		}
+	}
+	w.WriteHeader(200) // must have no content, but not a 204
+}