timeoutCache_test.go

Documentation: google.golang.org/grpc/internal/cache

     1  /*
     2   *
     3   * Copyright 2019 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  
    18  package cache
    19  
    20  import (
    21  	"strconv"
    22  	"sync"
    23  	"testing"
    24  	"time"
    25  
    26  	"google.golang.org/grpc/internal/grpctest"
    27  )
    28  
    29  const (
    30  	testCacheTimeout = 100 * time.Millisecond
    31  )
    32  
    33  type s struct {
    34  	grpctest.Tester
    35  }
    36  
    37  func Test(t *testing.T) {
    38  	grpctest.RunSubTests(t, s{})
    39  }
    40  
    41  func (c *TimeoutCache) getForTesting(key any) (*cacheEntry, bool) {
    42  	c.mu.Lock()
    43  	defer c.mu.Unlock()
    44  	r, ok := c.cache[key]
    45  	return r, ok
    46  }
    47  
    48  // TestCacheExpire attempts to add an entry to the cache and verifies that it
    49  // was added successfully. It then makes sure that on timeout, it's removed and
    50  // the associated callback is called.
    51  func (s) TestCacheExpire(t *testing.T) {
    52  	const k, v = 1, "1"
    53  	c := NewTimeoutCache(testCacheTimeout)
    54  
    55  	callbackChan := make(chan struct{})
    56  	c.Add(k, v, func() { close(callbackChan) })
    57  
    58  	if gotV, ok := c.getForTesting(k); !ok || gotV.item != v {
    59  		t.Fatalf("After Add(), before timeout, from cache got: %v, %v, want %v, %v", gotV.item, ok, v, true)
    60  	}
    61  	if l := c.Len(); l != 1 {
    62  		t.Fatalf("%d number of items in the cache, want 1", l)
    63  	}
    64  
    65  	select {
    66  	case <-callbackChan:
    67  	case <-time.After(testCacheTimeout * 2):
    68  		t.Fatalf("timeout waiting for callback")
    69  	}
    70  
    71  	if _, ok := c.getForTesting(k); ok {
    72  		t.Fatalf("After Add(), after timeout, from cache got: _, %v, want _, %v", ok, false)
    73  	}
    74  	if l := c.Len(); l != 0 {
    75  		t.Fatalf("%d number of items in the cache, want 0", l)
    76  	}
    77  }
    78  
    79  // TestCacheRemove attempts to remove an existing entry from the cache and
    80  // verifies that the entry is removed and the associated callback is not
    81  // invoked.
    82  func (s) TestCacheRemove(t *testing.T) {
    83  	const k, v = 1, "1"
    84  	c := NewTimeoutCache(testCacheTimeout)
    85  
    86  	callbackChan := make(chan struct{})
    87  	c.Add(k, v, func() { close(callbackChan) })
    88  
    89  	if got, ok := c.getForTesting(k); !ok || got.item != v {
    90  		t.Fatalf("After Add(), before timeout, from cache got: %v, %v, want %v, %v", got.item, ok, v, true)
    91  	}
    92  	if l := c.Len(); l != 1 {
    93  		t.Fatalf("%d number of items in the cache, want 1", l)
    94  	}
    95  
    96  	time.Sleep(testCacheTimeout / 2)
    97  
    98  	gotV, gotOK := c.Remove(k)
    99  	if !gotOK || gotV != v {
   100  		t.Fatalf("After Add(), before timeout, Remove() got: %v, %v, want %v, %v", gotV, gotOK, v, true)
   101  	}
   102  
   103  	if _, ok := c.getForTesting(k); ok {
   104  		t.Fatalf("After Add(), before timeout, after Remove(), from cache got: _, %v, want _, %v", ok, false)
   105  	}
   106  	if l := c.Len(); l != 0 {
   107  		t.Fatalf("%d number of items in the cache, want 0", l)
   108  	}
   109  
   110  	select {
   111  	case <-callbackChan:
   112  		t.Fatalf("unexpected callback after retrieve")
   113  	case <-time.After(testCacheTimeout * 2):
   114  	}
   115  }
   116  
   117  // TestCacheClearWithoutCallback attempts to clear all entries from the cache
   118  // and verifies that the associated callbacks are not invoked.
   119  func (s) TestCacheClearWithoutCallback(t *testing.T) {
   120  	var values []string
   121  	const itemCount = 3
   122  	for i := 0; i < itemCount; i++ {
   123  		values = append(values, strconv.Itoa(i))
   124  	}
   125  	c := NewTimeoutCache(testCacheTimeout)
   126  
   127  	done := make(chan struct{})
   128  	defer close(done)
   129  	callbackChan := make(chan struct{}, itemCount)
   130  
   131  	for i, v := range values {
   132  		callbackChanTemp := make(chan struct{})
   133  		c.Add(i, v, func() { close(callbackChanTemp) })
   134  		go func() {
   135  			select {
   136  			case <-callbackChanTemp:
   137  				callbackChan <- struct{}{}
   138  			case <-done:
   139  			}
   140  		}()
   141  	}
   142  
   143  	for i, v := range values {
   144  		if got, ok := c.getForTesting(i); !ok || got.item != v {
   145  			t.Fatalf("After Add(), before timeout, from cache got: %v, %v, want %v, %v", got.item, ok, v, true)
   146  		}
   147  	}
   148  	if l := c.Len(); l != itemCount {
   149  		t.Fatalf("%d number of items in the cache, want %d", l, itemCount)
   150  	}
   151  
   152  	time.Sleep(testCacheTimeout / 2)
   153  	c.Clear(false)
   154  
   155  	for i := range values {
   156  		if _, ok := c.getForTesting(i); ok {
   157  			t.Fatalf("After Add(), before timeout, after Remove(), from cache got: _, %v, want _, %v", ok, false)
   158  		}
   159  	}
   160  	if l := c.Len(); l != 0 {
   161  		t.Fatalf("%d number of items in the cache, want 0", l)
   162  	}
   163  
   164  	select {
   165  	case <-callbackChan:
   166  		t.Fatalf("unexpected callback after Clear")
   167  	case <-time.After(testCacheTimeout * 2):
   168  	}
   169  }
   170  
   171  // TestCacheClearWithCallback attempts to clear all entries from the cache and
   172  // verifies that the associated callbacks are invoked.
   173  func (s) TestCacheClearWithCallback(t *testing.T) {
   174  	var values []string
   175  	const itemCount = 3
   176  	for i := 0; i < itemCount; i++ {
   177  		values = append(values, strconv.Itoa(i))
   178  	}
   179  	c := NewTimeoutCache(time.Hour)
   180  
   181  	testDone := make(chan struct{})
   182  	defer close(testDone)
   183  
   184  	var wg sync.WaitGroup
   185  	wg.Add(itemCount)
   186  	for i, v := range values {
   187  		callbackChanTemp := make(chan struct{})
   188  		c.Add(i, v, func() { close(callbackChanTemp) })
   189  		go func() {
   190  			defer wg.Done()
   191  			select {
   192  			case <-callbackChanTemp:
   193  			case <-testDone:
   194  			}
   195  		}()
   196  	}
   197  
   198  	allGoroutineDone := make(chan struct{}, itemCount)
   199  	go func() {
   200  		wg.Wait()
   201  		close(allGoroutineDone)
   202  	}()
   203  
   204  	for i, v := range values {
   205  		if got, ok := c.getForTesting(i); !ok || got.item != v {
   206  			t.Fatalf("After Add(), before timeout, from cache got: %v, %v, want %v, %v", got.item, ok, v, true)
   207  		}
   208  	}
   209  	if l := c.Len(); l != itemCount {
   210  		t.Fatalf("%d number of items in the cache, want %d", l, itemCount)
   211  	}
   212  
   213  	time.Sleep(testCacheTimeout / 2)
   214  	c.Clear(true)
   215  
   216  	for i := range values {
   217  		if _, ok := c.getForTesting(i); ok {
   218  			t.Fatalf("After Add(), before timeout, after Remove(), from cache got: _, %v, want _, %v", ok, false)
   219  		}
   220  	}
   221  	if l := c.Len(); l != 0 {
   222  		t.Fatalf("%d number of items in the cache, want 0", l)
   223  	}
   224  
   225  	select {
   226  	case <-allGoroutineDone:
   227  	case <-time.After(testCacheTimeout * 2):
   228  		t.Fatalf("timeout waiting for all callbacks")
   229  	}
   230  }
   231  
   232  // TestCacheRetrieveTimeoutRace simulates the case where an entry's timer fires
   233  // around the same time that Remove() is called for it. It verifies that there
   234  // is no deadlock.
   235  func (s) TestCacheRetrieveTimeoutRace(t *testing.T) {
   236  	c := NewTimeoutCache(time.Nanosecond)
   237  
   238  	done := make(chan struct{})
   239  	go func() {
   240  		for i := 0; i < 1000; i++ {
   241  			// Add starts a timer with 1 ns timeout, then remove will race
   242  			// with the timer.
   243  			c.Add(i, strconv.Itoa(i), func() {})
   244  			c.Remove(i)
   245  		}
   246  		close(done)
   247  	}()
   248  
   249  	select {
   250  	case <-time.After(time.Second):
   251  		t.Fatalf("Test didn't finish within 1 second. Deadlock")
   252  	case <-done:
   253  	}
   254  }
   255
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