| 1 | // Package bakeoff is the bakeoff's measurement harness: it drives any app |
| 2 | // that keeps CONTRACT.md and records what it measures in results/<slug>.json. |
| 3 | package bakeoff |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "io" |
| 8 | "net/http" |
| 9 | "net/http/cookiejar" |
| 10 | "net/url" |
| 11 | "regexp" |
| 12 | "strings" |
| 13 | "time" |
| 14 | ) |
| 15 | |
| 16 | // Session is one visitor: a cookie jar (so one list), an Origin header |
| 17 | // matching the app, and a client that never follows redirects. |
| 18 | type Session struct { |
| 19 | Base *url.URL |
| 20 | Client *http.Client |
| 21 | // ToggleID is the item load tests toggle, chosen once by Seed so a |
| 22 | // load step never has to fetch the page from an app under strain. |
| 23 | ToggleID string |
| 24 | } |
| 25 | |
| 26 | // SessionNoFetch starts a visitor for the app at base without making any |
| 27 | // request (so a sleeping instance stays asleep until the caller's first one). |
| 28 | func SessionNoFetch(base string) (*Session, error) { |
| 29 | u, err := url.Parse(strings.TrimRight(base, "/")) |
| 30 | if err != nil { |
| 31 | return nil, err |
| 32 | } |
| 33 | jar, _ := cookiejar.New(nil) |
| 34 | return &Session{Base: u, Client: &http.Client{ |
| 35 | Jar: jar, |
| 36 | Timeout: 60 * time.Second, |
| 37 | CheckRedirect: func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse }, |
| 38 | }}, nil |
| 39 | } |
| 40 | |
| 41 | // NewSession starts a visitor for the app at base and fetches / once so the |
| 42 | // app sets its list cookie. |
| 43 | func NewSession(base string) (*Session, error) { |
| 44 | s, err := SessionNoFetch(base) |
| 45 | if err != nil { |
| 46 | return nil, err |
| 47 | } |
| 48 | if _, err := s.get("/"); err != nil { |
| 49 | return nil, err |
| 50 | } |
| 51 | return s, nil |
| 52 | } |
| 53 | |
| 54 | func (s *Session) origin() string { return s.Base.Scheme + "://" + s.Base.Host } |
| 55 | |
| 56 | func (s *Session) get(path string) (string, error) { |
| 57 | res, err := s.Client.Get(s.Base.String() + path) |
| 58 | if err != nil { |
| 59 | return "", err |
| 60 | } |
| 61 | defer res.Body.Close() |
| 62 | b, err := io.ReadAll(res.Body) |
| 63 | if res.StatusCode != 200 { |
| 64 | return "", fmt.Errorf("GET %s: %s", path, res.Status) |
| 65 | } |
| 66 | return string(b), err |
| 67 | } |
| 68 | |
| 69 | func (s *Session) post(path string, form url.Values) error { |
| 70 | req, _ := http.NewRequest("POST", s.Base.String()+path, strings.NewReader(form.Encode())) |
| 71 | req.Header.Set("Content-Type", "application/x-www-form-urlencoded") |
| 72 | req.Header.Set("Origin", s.origin()) |
| 73 | res, err := s.Client.Do(req) |
| 74 | if err != nil { |
| 75 | return err |
| 76 | } |
| 77 | io.Copy(io.Discard, res.Body) |
| 78 | res.Body.Close() |
| 79 | if res.StatusCode != http.StatusSeeOther { |
| 80 | return fmt.Errorf("POST %s: %s, want 303", path, res.Status) |
| 81 | } |
| 82 | return nil |
| 83 | } |
| 84 | |
| 85 | // Add creates one item. |
| 86 | func (s *Session) Add(title string) error { |
| 87 | return s.post("/todos", url.Values{"title": {title}, "filter": {"all"}}) |
| 88 | } |
| 89 | |
| 90 | // Toggle flips one item. |
| 91 | func (s *Session) Toggle(id string) error { |
| 92 | return s.post("/todos/"+id+"/toggle", url.Values{"filter": {"all"}}) |
| 93 | } |
| 94 | |
| 95 | var liID = regexp.MustCompile(`<li\b[^>]*\bdata-id="([^"]+)"`) |
| 96 | |
| 97 | // IDs lists the item ids shown on the page at path, in order. |
| 98 | func (s *Session) IDs(path string) ([]string, error) { |
| 99 | body, err := s.get(path) |
| 100 | if err != nil { |
| 101 | return nil, err |
| 102 | } |
| 103 | var ids []string |
| 104 | for _, m := range liID.FindAllStringSubmatch(body, -1) { |
| 105 | ids = append(ids, m[1]) |
| 106 | } |
| 107 | return ids, nil |
| 108 | } |
| 109 | |
| 110 | // CookieHeader is the Cookie header this visitor sends, for tools like oha. |
| 111 | func (s *Session) CookieHeader() string { |
| 112 | var parts []string |
| 113 | for _, c := range s.Client.Jar.Cookies(s.Base) { |
| 114 | parts = append(parts, c.Name+"="+c.Value) |
| 115 | } |
| 116 | return strings.Join(parts, "; ") |
| 117 | } |
| 118 | |
| 119 | // Seed adds "item 1".."item n" and completes every second one, returning |
| 120 | // the ids in list order. |
| 121 | func Seed(s *Session, n int) ([]string, error) { |
| 122 | for i := 1; i <= n; i++ { |
| 123 | if err := s.Add(fmt.Sprintf("item %d", i)); err != nil { |
| 124 | return nil, err |
| 125 | } |
| 126 | } |
| 127 | ids, err := s.IDs("/") |
| 128 | if err != nil { |
| 129 | return nil, err |
| 130 | } |
| 131 | if len(ids) != n { |
| 132 | return nil, fmt.Errorf("seeded %d items, page shows %d", n, len(ids)) |
| 133 | } |
| 134 | for i := 1; i < n; i += 2 { |
| 135 | if err := s.Toggle(ids[i]); err != nil { |
| 136 | return nil, err |
| 137 | } |
| 138 | } |
| 139 | s.ToggleID = ids[0] |
| 140 | return ids, nil |
| 141 | } |
| 142 | |
amadan