| 1 | package edge |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "io" |
| 7 | "net" |
| 8 | "net/http" |
| 9 | "net/http/httptest" |
| 10 | "os" |
| 11 | "path/filepath" |
| 12 | "strconv" |
| 13 | "strings" |
| 14 | "sync" |
| 15 | "sync/atomic" |
| 16 | "syscall" |
| 17 | "testing" |
| 18 | "time" |
| 19 | ) |
| 20 | |
| 21 | // fakeGens is a GenSource a test drives by hand: switchTo is plan 3's |
| 22 | // switch as the edge sees it, sleep is a stop. |
| 23 | type fakeGens struct { |
| 24 | mu sync.Mutex |
| 25 | on bool |
| 26 | cur map[string]GenInfo // host -> current generation; absent = no current generation |
| 27 | last map[string]uint64 // host -> CacheGen |
| 28 | asks int // AppSocket calls |
| 29 | retired []func(host, socket string) |
| 30 | // onServing, when set, runs after every ServingGen answer, with no lock |
| 31 | // held: a test's way to land a switch between the pool choice and the |
| 32 | // dial. |
| 33 | onServing func() |
| 34 | } |
| 35 | |
| 36 | func newFakeGens(on bool) *fakeGens { |
| 37 | return &fakeGens{on: on, cur: map[string]GenInfo{}, last: map[string]uint64{}} |
| 38 | } |
| 39 | |
| 40 | func (f *fakeGens) GenerationsOn() bool { return f.on } |
| 41 | |
| 42 | func (f *fakeGens) AppSocket(host string) (string, bool) { |
| 43 | f.mu.Lock() |
| 44 | defer f.mu.Unlock() |
| 45 | f.asks++ |
| 46 | g, ok := f.cur[host] |
| 47 | return g.Socket, ok |
| 48 | } |
| 49 | |
| 50 | func (f *fakeGens) ServingGen(host string) (GenInfo, bool) { |
| 51 | f.mu.Lock() |
| 52 | g, ok := f.cur[host] |
| 53 | hook := f.onServing |
| 54 | f.mu.Unlock() |
| 55 | if hook != nil { |
| 56 | hook() |
| 57 | } |
| 58 | return g, ok |
| 59 | } |
| 60 | |
| 61 | func (f *fakeGens) CacheGen(host string) (uint64, bool) { |
| 62 | f.mu.Lock() |
| 63 | defer f.mu.Unlock() |
| 64 | n, ok := f.last[host] |
| 65 | return n, ok |
| 66 | } |
| 67 | |
| 68 | func (f *fakeGens) OnGenRetired(fn func(host, socket string)) { |
| 69 | f.mu.Lock() |
| 70 | defer f.mu.Unlock() |
| 71 | f.retired = append(f.retired, fn) |
| 72 | } |
| 73 | |
| 74 | // switchTo makes g host's current generation, then tells the retire hooks |
| 75 | // about the one it replaced. |
| 76 | func (f *fakeGens) switchTo(host string, g GenInfo) { |
| 77 | f.mu.Lock() |
| 78 | old, had := f.cur[host] |
| 79 | f.cur[host], f.last[host] = g, g.N |
| 80 | hooks := append([]func(string, string){}, f.retired...) |
| 81 | f.mu.Unlock() |
| 82 | if had { |
| 83 | for _, fn := range hooks { |
| 84 | fn(host, old.Socket) |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | // sleep takes host's current generation away and keeps its number for the |
| 90 | // cache, as the activator does at a stop. |
| 91 | func (f *fakeGens) sleep(host string) { |
| 92 | f.mu.Lock() |
| 93 | old, had := f.cur[host] |
| 94 | delete(f.cur, host) |
| 95 | hooks := append([]func(string, string){}, f.retired...) |
| 96 | f.mu.Unlock() |
| 97 | if had { |
| 98 | for _, fn := range hooks { |
| 99 | fn(host, old.Socket) |
| 100 | } |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | func (f *fakeGens) askCount() int { |
| 105 | f.mu.Lock() |
| 106 | defer f.mu.Unlock() |
| 107 | return f.asks |
| 108 | } |
| 109 | |
| 110 | // genSockDir is a short directory for generation sockets. Run with |
| 111 | // TMPDIR=/tmp/k: a socket path must stay under sockaddr_un's 108 bytes. |
| 112 | func genSockDir(t *testing.T) string { |
| 113 | t.Helper() |
| 114 | dir, err := os.MkdirTemp("", "e") |
| 115 | if err != nil { |
| 116 | t.Fatal(err) |
| 117 | } |
| 118 | t.Cleanup(func() { os.RemoveAll(dir) }) |
| 119 | return dir |
| 120 | } |
| 121 | |
| 122 | // genApp is one generation's process: an HTTP server on a unix socket that |
| 123 | // counts the connections it opened and closed. |
| 124 | type genApp struct { |
| 125 | sock string |
| 126 | ln net.Listener |
| 127 | opened, closed atomic.Int64 |
| 128 | srv *http.Server |
| 129 | } |
| 130 | |
| 131 | func startGenApp(t *testing.T, sock string, h http.Handler) *genApp { |
| 132 | t.Helper() |
| 133 | ln, err := net.Listen("unix", sock) |
| 134 | if err != nil { |
| 135 | if errors.Is(err, syscall.EPERM) || strings.Contains(err.Error(), "operation not permitted") { |
| 136 | t.Skipf("unix-socket listeners not permitted in this environment: %v", err) |
| 137 | } |
| 138 | t.Fatalf("listen %s: %v", sock, err) |
| 139 | } |
| 140 | a := &genApp{sock: sock, ln: ln} |
| 141 | a.srv = &http.Server{Handler: h, ConnState: func(_ net.Conn, st http.ConnState) { |
| 142 | switch st { |
| 143 | case http.StateNew: |
| 144 | a.opened.Add(1) |
| 145 | case http.StateClosed, http.StateHijacked: |
| 146 | a.closed.Add(1) |
| 147 | } |
| 148 | }} |
| 149 | go a.srv.Serve(ln) |
| 150 | t.Cleanup(func() { a.srv.Close() }) |
| 151 | return a |
| 152 | } |
| 153 | |
| 154 | // stop is the generation's process exiting: the server and its listener close now, |
| 155 | // so the socket file is unlinked before stop returns (srv.Close alone misses a |
| 156 | // listener Serve has not registered yet, and Serve's late close would unlink the |
| 157 | // path by name, possibly a replacement's socket). |
| 158 | func (a *genApp) stop() { a.srv.Close(); a.ln.Close() } |
| 159 | |
| 160 | // body answers b with cache-control cc ("" for none). |
| 161 | func body(b, cc string) http.Handler { |
| 162 | return http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) { |
| 163 | if cc != "" { |
| 164 | w.Header().Set("Cache-Control", cc) |
| 165 | } |
| 166 | io.WriteString(w, b) |
| 167 | }) |
| 168 | } |
| 169 | |
| 170 | func serve(t *testing.T, h http.Handler, url string) *httptest.ResponseRecorder { |
| 171 | t.Helper() |
| 172 | rec := httptest.NewRecorder() |
| 173 | h.ServeHTTP(rec, httptest.NewRequest("GET", url, nil)) |
| 174 | return rec |
| 175 | } |
| 176 | |
| 177 | // Each retry asks the source again: a dial that races a switch reaches the |
| 178 | // generation that is current by the time it retries. |
| 179 | func TestDialUnixRetryingAsksAgainOnEveryRetry(t *testing.T) { |
| 180 | dir := genSockDir(t) |
| 181 | live := startGenApp(t, filepath.Join(dir, "2.sock"), body("B", "")) |
| 182 | var asks atomic.Int64 |
| 183 | resolve := func() (string, bool) { |
| 184 | switch asks.Add(1) { |
| 185 | case 1: |
| 186 | return "", false // between generations: no current one yet |
| 187 | case 2: |
| 188 | return filepath.Join(dir, "1.sock"), true // a retired generation: its file is gone |
| 189 | default: |
| 190 | return live.sock, true |
| 191 | } |
| 192 | } |
| 193 | conn, err := dialUnixRetrying(context.Background(), &net.Dialer{}, resolve) |
| 194 | if err != nil { |
| 195 | t.Fatalf("dial: %v", err) |
| 196 | } |
| 197 | conn.Close() |
| 198 | if got := asks.Load(); got != 3 { |
| 199 | t.Fatalf("resolve asked %d times, want 3 (once per attempt)", got) |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | // A connection to generation n is never reused for n+1, and n's idle |
| 204 | // connections close when it stops being current. The version header names |
| 205 | // the build of the generation that served each request. |
| 206 | func TestAppSocketProxyFollowsTheCurrentGeneration(t *testing.T) { |
| 207 | dir := genSockDir(t) |
| 208 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 209 | b := startGenApp(t, filepath.Join(dir, "b.sock"), body("B", "")) |
| 210 | src := newFakeGens(true) |
| 211 | pools := NewGenPools() |
| 212 | src.OnGenRetired(pools.Retire) |
| 213 | const host = "inst.example.com" |
| 214 | src.switchTo(host, GenInfo{Socket: a.sock, N: 1, Build: "v1"}) |
| 215 | p := appSocketProxy(host, src, pools) |
| 216 | |
| 217 | for i := 0; i < 2; i++ { |
| 218 | rec := serve(t, p, "http://inst.example.com/") |
| 219 | if rec.Body.String() != "A" || rec.Header().Get("X-Carlos-Version") != "v1" { |
| 220 | t.Fatalf("request %d: %q version %q, want A from v1", i, rec.Body.String(), rec.Header().Get("X-Carlos-Version")) |
| 221 | } |
| 222 | } |
| 223 | if got := a.opened.Load(); got != 1 { |
| 224 | t.Fatalf("generation 1 saw %d connections, want 1 (keep-alive reused)", got) |
| 225 | } |
| 226 | |
| 227 | src.switchTo(host, GenInfo{Socket: b.sock, N: 2, Build: "v2"}) |
| 228 | rec := serve(t, p, "http://inst.example.com/") |
| 229 | if rec.Body.String() != "B" || rec.Header().Get("X-Carlos-Version") != "v2" { |
| 230 | t.Fatalf("after the switch: %q version %q, want B from v2", rec.Body.String(), rec.Header().Get("X-Carlos-Version")) |
| 231 | } |
| 232 | if got := a.opened.Load(); got != 1 { |
| 233 | t.Fatalf("generation 1 saw %d connections after the switch, want still 1", got) |
| 234 | } |
| 235 | deadline := time.Now().Add(2 * time.Second) |
| 236 | for a.closed.Load() != 1 && time.Now().Before(deadline) { |
| 237 | time.Sleep(10 * time.Millisecond) |
| 238 | } |
| 239 | if got := a.closed.Load(); got != 1 { |
| 240 | t.Fatalf("generation 1's idle connection was not closed at retirement (closed=%d)", got) |
| 241 | } |
| 242 | if got := pools.Len(); got != 1 { |
| 243 | t.Fatalf("%d pools live, want 1 (the retired one forgotten)", got) |
| 244 | } |
| 245 | } |
| 246 | |
| 247 | // Spec §7.2: the version header and the cache's generation name the |
| 248 | // generation whose connection carried the request. Here the switch lands |
| 249 | // between the pool choice and the dial. With a pool whose dial re-resolves |
| 250 | // AppSocket, the request reached B while it was stamped and tagged as A. |
| 251 | func TestAppSocketProxyAttributesTheConnectionsGeneration(t *testing.T) { |
| 252 | const host = "inst.example.com" |
| 253 | // Rev 17: a switch that lands before the dial completes sends the request |
| 254 | // to the new current generation, even though the retiring one still |
| 255 | // accepts. Its response is attributed to the generation that served it. |
| 256 | t.Run("a switch before the dial completes", func(t *testing.T) { |
| 257 | dir := genSockDir(t) |
| 258 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 259 | b := startGenApp(t, filepath.Join(dir, "b.sock"), body("B", "")) |
| 260 | src := newFakeGens(true) |
| 261 | src.switchTo(host, GenInfo{Socket: a.sock, N: 1, Build: "v1"}) |
| 262 | var once sync.Once |
| 263 | src.onServing = func() { |
| 264 | once.Do(func() { src.switchTo(host, GenInfo{Socket: b.sock, N: 2, Build: "v2"}) }) |
| 265 | } |
| 266 | p := appSocketProxy(host, src, NewGenPools()) |
| 267 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 268 | rec := httptest.NewRecorder() |
| 269 | p.ServeHTTP(rec, r) |
| 270 | _, n, _ := servedGen(r) |
| 271 | if rec.Body.String() != "B" || rec.Header().Get("X-Carlos-Version") != "v2" || n != 2 { |
| 272 | t.Fatalf("served %q, version %q, generation %d: want B, v2, 2 (retried on the current generation)", |
| 273 | rec.Body.String(), rec.Header().Get("X-Carlos-Version"), n) |
| 274 | } |
| 275 | if got := b.opened.Load(); got < 1 { |
| 276 | t.Fatal("generation 2 was never reached") |
| 277 | } |
| 278 | _ = a |
| 279 | }) |
| 280 | // A proxied POST streams its body: no GetBody, unknown length. A switch |
| 281 | // before the dial completes must not turn it into a 502. The generation |
| 282 | // is settled before a byte of the body is read, so the body goes, whole, |
| 283 | // to the current generation. Retrying only replayable requests failed it. |
| 284 | t.Run("a streaming POST across a switch", func(t *testing.T) { |
| 285 | dir := genSockDir(t) |
| 286 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 287 | echo := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 288 | b, _ := io.ReadAll(r.Body) |
| 289 | io.WriteString(w, "B:"+string(b)) |
| 290 | }) |
| 291 | b := startGenApp(t, filepath.Join(dir, "b.sock"), echo) |
| 292 | src := newFakeGens(true) |
| 293 | src.switchTo(host, GenInfo{Socket: a.sock, N: 1, Build: "v1"}) |
| 294 | var once sync.Once |
| 295 | src.onServing = func() { |
| 296 | once.Do(func() { |
| 297 | a.stop() // generation 1 has gone: its socket file with it |
| 298 | src.switchTo(host, GenInfo{Socket: b.sock, N: 2, Build: "v2"}) |
| 299 | }) |
| 300 | } |
| 301 | pr, pw := io.Pipe() |
| 302 | go func() { |
| 303 | io.WriteString(pw, "hello, ") |
| 304 | io.WriteString(pw, "world") |
| 305 | pw.Close() |
| 306 | }() |
| 307 | req := httptest.NewRequest("POST", "http://inst.example.com/form", pr) |
| 308 | req.ContentLength = -1 |
| 309 | if req.GetBody != nil { |
| 310 | t.Fatal("fixture: the request must have no GetBody") |
| 311 | } |
| 312 | r, _ := withOutcome(req) |
| 313 | rec := httptest.NewRecorder() |
| 314 | appSocketProxy(host, src, NewGenPools()).ServeHTTP(rec, r) |
| 315 | if rec.Code != http.StatusOK || rec.Body.String() != "B:hello, world" || rec.Header().Get("X-Carlos-Version") != "v2" { |
| 316 | t.Fatalf("status %d, body %q, version %q: want 200, the whole body at generation 2, v2", |
| 317 | rec.Code, rec.Body.String(), rec.Header().Get("X-Carlos-Version")) |
| 318 | } |
| 319 | _ = b |
| 320 | }) |
| 321 | t.Run("the sampled generation is gone", func(t *testing.T) { |
| 322 | dir := genSockDir(t) |
| 323 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 324 | b := startGenApp(t, filepath.Join(dir, "b.sock"), body("B", "")) |
| 325 | src := newFakeGens(true) |
| 326 | src.switchTo(host, GenInfo{Socket: a.sock, N: 1, Build: "v1"}) |
| 327 | var once sync.Once |
| 328 | src.onServing = func() { |
| 329 | once.Do(func() { |
| 330 | a.stop() // A has exited: its socket file is gone |
| 331 | src.switchTo(host, GenInfo{Socket: b.sock, N: 2, Build: "v2"}) |
| 332 | }) |
| 333 | } |
| 334 | p := appSocketProxy(host, src, NewGenPools()) |
| 335 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 336 | rec := httptest.NewRecorder() |
| 337 | p.ServeHTTP(rec, r) |
| 338 | _, n, _ := servedGen(r) |
| 339 | if rec.Body.String() != "B" || rec.Header().Get("X-Carlos-Version") != "v2" || n != 2 { |
| 340 | t.Fatalf("served %q, version %q, generation %d: want B, v2, 2 (sent again on the current pool)", |
| 341 | rec.Body.String(), rec.Header().Get("X-Carlos-Version"), n) |
| 342 | } |
| 343 | }) |
| 344 | // A foreign row's generations share one path. Generation 1's pool, chosen |
| 345 | // an instant before the hold, dials that path after generation 2 has |
| 346 | // bound it: the connection reaches 2, and a dial that trusts the path |
| 347 | // stamps 2's response as 1 and keeps the connection in 1's pool. |
| 348 | t.Run("a foreign row's path now belongs to the replacement", func(t *testing.T) { |
| 349 | dir := genSockDir(t) |
| 350 | path := filepath.Join(dir, "canonical.sock") |
| 351 | a := startGenApp(t, path, body("A", "")) |
| 352 | src := newFakeGens(true) |
| 353 | src.switchTo(host, GenInfo{Socket: path, N: 1, Build: "v1"}) |
| 354 | var once sync.Once |
| 355 | var b *genApp |
| 356 | src.onServing = func() { |
| 357 | once.Do(func() { |
| 358 | a.stop() // the hold stops 1; its socket file goes |
| 359 | b = startGenApp(t, path, body("B", "")) |
| 360 | src.switchTo(host, GenInfo{Socket: path, N: 2, Build: "v2"}) |
| 361 | }) |
| 362 | } |
| 363 | p := appSocketProxy(host, src, NewGenPools()) |
| 364 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 365 | rec := httptest.NewRecorder() |
| 366 | p.ServeHTTP(rec, r) |
| 367 | _, n, _ := servedGen(r) |
| 368 | if rec.Body.String() != "B" || rec.Header().Get("X-Carlos-Version") != "v2" || n != 2 { |
| 369 | t.Fatalf("served %q, version %q, generation %d: want B, v2, 2 (never attributed to the old generation)", |
| 370 | rec.Body.String(), rec.Header().Get("X-Carlos-Version"), n) |
| 371 | } |
| 372 | if b == nil || b.opened.Load() < 1 { |
| 373 | t.Fatal("the replacement was never reached") |
| 374 | } |
| 375 | }) |
| 376 | } |
| 377 | |
| 378 | // The generation that carried a request is recorded on its outcome, for the |
| 379 | // cache to tag with. |
| 380 | func TestAppSocketProxyNotesTheServedGeneration(t *testing.T) { |
| 381 | dir := genSockDir(t) |
| 382 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 383 | src := newFakeGens(true) |
| 384 | src.switchTo("inst.example.com", GenInfo{Socket: a.sock, N: 7, Build: "v1"}) |
| 385 | p := appSocketProxy("inst.example.com", src, NewGenPools()) |
| 386 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 387 | p.ServeHTTP(httptest.NewRecorder(), r) |
| 388 | if host, n, ok := servedGen(r); !ok || host != "inst.example.com" || n != 7 { |
| 389 | t.Fatalf("servedGen = %q %d %v, want inst.example.com 7", host, n, ok) |
| 390 | } |
| 391 | } |
| 392 | |
| 393 | // With no current generation the request waits inside the dial's window for |
| 394 | // one, then goes the normal way: through that generation's pool, stamped |
| 395 | // with its build and tagged with its number (spec §7.2). An unbound one-shot |
| 396 | // transport returned the response unattributed, with no platform version. |
| 397 | func TestAppSocketProxyWaitsForAGeneration(t *testing.T) { |
| 398 | dir := genSockDir(t) |
| 399 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 400 | src := newFakeGens(true) |
| 401 | pools := NewGenPools() |
| 402 | p := appSocketProxy("inst.example.com", src, pools) |
| 403 | go func() { |
| 404 | time.Sleep(300 * time.Millisecond) |
| 405 | src.switchTo("inst.example.com", GenInfo{Socket: a.sock, N: 3, Build: "v1"}) |
| 406 | }() |
| 407 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 408 | rec := httptest.NewRecorder() |
| 409 | p.ServeHTTP(rec, r) |
| 410 | if rec.Body.String() != "A" || rec.Header().Get("X-Carlos-Version") != "v1" { |
| 411 | t.Fatalf("body %q, version %q: want A from v1 once the generation appeared", rec.Body.String(), rec.Header().Get("X-Carlos-Version")) |
| 412 | } |
| 413 | if host, n, ok := servedGen(r); !ok || host != "inst.example.com" || n != 3 { |
| 414 | t.Fatalf("servedGen = %q %d %v, want generation 3", host, n, ok) |
| 415 | } |
| 416 | if pools.Len() != 1 { |
| 417 | t.Fatalf("%d pools, want generation 3's", pools.Len()) |
| 418 | } |
| 419 | } |
| 420 | |
| 421 | // A request that sampled generation n before a switch must not leave n's |
| 422 | // pool behind when it resumes after Retire removed it: the pool is only |
| 423 | // published for a generation that is still current. The switch lands at the |
| 424 | // request's own sampling call, the instant between choosing n and asking for |
| 425 | // its pool, and repeats over many generations; the set stays at most one pool |
| 426 | // and every request is served by the generation current when it finished. |
| 427 | func TestGenPoolsRetiredGenerationIsNotRecreated(t *testing.T) { |
| 428 | const ( |
| 429 | host = "inst.example.com" |
| 430 | swaps = 20 |
| 431 | ) |
| 432 | dir := genSockDir(t) |
| 433 | apps := make([]*genApp, swaps+2) |
| 434 | for n := 1; n < len(apps); n++ { |
| 435 | apps[n] = startGenApp(t, filepath.Join(dir, strconv.Itoa(n)+".sock"), body("G"+strconv.Itoa(n), "")) |
| 436 | } |
| 437 | info := func(n int) GenInfo { |
| 438 | return GenInfo{Socket: apps[n].sock, N: uint64(n), Build: "v" + strconv.Itoa(n)} |
| 439 | } |
| 440 | src := newFakeGens(true) |
| 441 | pools := NewGenPools() |
| 442 | src.OnGenRetired(pools.Retire) |
| 443 | src.switchTo(host, info(1)) |
| 444 | p := appSocketProxy(host, src, pools) |
| 445 | |
| 446 | for n := 1; n <= swaps; n++ { |
| 447 | var once sync.Once |
| 448 | next := n + 1 |
| 449 | src.onServing = func() { once.Do(func() { src.switchTo(host, info(next)) }) } |
| 450 | r, _ := withOutcome(httptest.NewRequest("GET", "http://inst.example.com/", nil)) |
| 451 | rec := httptest.NewRecorder() |
| 452 | p.ServeHTTP(rec, r) |
| 453 | want := "G" + strconv.Itoa(next) |
| 454 | if rec.Body.String() != want || rec.Header().Get("X-Carlos-Version") != "v"+strconv.Itoa(next) { |
| 455 | t.Fatalf("switch %d: served %q version %q, want %s from v%d", |
| 456 | n, rec.Body.String(), rec.Header().Get("X-Carlos-Version"), want, next) |
| 457 | } |
| 458 | if _, got, _ := servedGen(r); got != uint64(next) { |
| 459 | t.Fatalf("switch %d: attributed to generation %d, want %d", n, got, next) |
| 460 | } |
| 461 | if got := pools.Len(); got > 1 { |
| 462 | t.Fatalf("switch %d: %d pools live, want at most 1 (a retired generation's pool was recreated)", n, got) |
| 463 | } |
| 464 | } |
| 465 | } |
| 466 | |
| 467 | // flappingGens answers a different generation on every ServingGen call, so no |
| 468 | // sampled generation is ever still current when its pool is asked for. |
| 469 | type flappingGens struct { |
| 470 | *fakeGens |
| 471 | sock string |
| 472 | n atomic.Uint64 |
| 473 | } |
| 474 | |
| 475 | func (f *flappingGens) ServingGen(string) (GenInfo, bool) { |
| 476 | return GenInfo{Socket: f.sock, N: f.n.Add(1), Build: "v"}, true |
| 477 | } |
| 478 | |
| 479 | type closeCounter struct { |
| 480 | io.Reader |
| 481 | closed atomic.Int64 |
| 482 | } |
| 483 | |
| 484 | func (c *closeCounter) Close() error { c.closed.Add(1); return nil } |
| 485 | |
| 486 | // A request whose sampled generation is refused again and again does not spin |
| 487 | // and does not leave a pool behind: after a few refusals it gives up with the |
| 488 | // generation-moved error, as exhausted retries do, and its body is released. |
| 489 | func TestGenRoundTripperGivesUpWhenEveryGenerationIsStale(t *testing.T) { |
| 490 | dir := genSockDir(t) |
| 491 | a := startGenApp(t, filepath.Join(dir, "a.sock"), body("A", "")) |
| 492 | src := &flappingGens{fakeGens: newFakeGens(true), sock: a.sock} |
| 493 | pools := NewGenPools() |
| 494 | rt := &genRoundTripper{host: "inst.example.com", src: src, pools: pools} |
| 495 | b := &closeCounter{Reader: strings.NewReader("x")} |
| 496 | req := httptest.NewRequest("POST", "http://inst.example.com/", b) |
| 497 | _, err := rt.RoundTrip(req) |
| 498 | var moved *genMovedError |
| 499 | if !errors.As(err, &moved) { |
| 500 | t.Fatalf("RoundTrip error = %v, want a *genMovedError", err) |
| 501 | } |
| 502 | if got := pools.Len(); got != 0 { |
| 503 | t.Fatalf("%d pools live, want none for a generation that was never current", got) |
| 504 | } |
| 505 | if got := b.closed.Load(); got != 1 { |
| 506 | t.Fatalf("body closed %d times, want 1", got) |
| 507 | } |
| 508 | } |
| 509 | |
amadan