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package balancer
import (
"encoding/json"
"fmt"
"strings"
"sync"
"testing"
"time"
"github.com/stretchr/testify/require"
"google.golang.org/grpc/resolver"
)
func TestServiceConfig(t *testing.T) {
configureBuilderTest(3)
tcc := &testClientConn{}
lbBuilder.Build(resolver.Target{}, tcc, resolver.BuildOption{})
configUpdates := tcc.ConfigUpdates()
require.Len(t, configUpdates, 1, "expect exactly one config update")
svcConfig := struct{ LoadBalancingPolicy string }{}
require.NoError(t, json.NewDecoder(strings.NewReader(configUpdates[0])).Decode(&svcConfig))
require.Equal(t, "round_robin", svcConfig.LoadBalancingPolicy)
}
func TestAddressUpdatesSmallestPool(t *testing.T) {
// The smallest number of addresses is 2: 1 standby, and 1 active.
addrs := configureBuilderTest(2)
tcc := &testClientConn{}
lbBuilder.Build(resolver.Target{}, tcc, resolver.BuildOption{})
// Simulate some random updates
RemoveAddress(addrs[0])
RemoveAddress(addrs[0])
AddAddress(addrs[0])
RemoveAddress(addrs[1])
RemoveAddress(addrs[0])
AddAddress(addrs[1])
AddAddress(addrs[1])
RemoveAddress(addrs[1])
RemoveAddress(addrs[1])
RemoveAddress(addrs[1])
RemoveAddress(addrs[0])
AddAddress(addrs[0])
addrUpdates := tcc.AddrUpdates()
require.True(t, len(addrUpdates) > 0, "expected at least one address update")
expectedActive := len(addrs) - 1 // subtract 1 for the standby
for _, update := range addrUpdates {
require.Equal(t, expectedActive, len(update))
}
}
func TestAddressUpdatesRoundRobinPool(t *testing.T) {
// With 3 addresses in the pool, 2 will be active.
addrs := configureBuilderTest(3)
tcc := &testClientConn{}
lbBuilder.Build(resolver.Target{}, tcc, resolver.BuildOption{})
// Simulate some random updates
RemoveAddress(addrs[0])
RemoveAddress(addrs[0])
RemoveAddress(addrs[2])
AddAddress(addrs[0])
RemoveAddress(addrs[1])
RemoveAddress(addrs[0])
AddAddress(addrs[2])
AddAddress(addrs[1])
AddAddress(addrs[1])
RemoveAddress(addrs[1])
RemoveAddress(addrs[2])
RemoveAddress(addrs[1])
AddAddress(addrs[1])
RemoveAddress(addrs[2])
RemoveAddress(addrs[1])
RemoveAddress(addrs[0])
AddAddress(addrs[0])
addrUpdates := tcc.AddrUpdates()
require.True(t, len(addrUpdates) > 0, "expected at least one address update")
expectedActive := len(addrs) - 1 // subtract 1 for the standby
for _, update := range addrUpdates {
require.Equal(t, expectedActive, len(update))
}
}
func TestRemovals(t *testing.T) {
okActions := []action{
{add: "foo"},
{add: "bar"},
{add: "qux"},
{remove: "bar"},
{add: "baz"},
{remove: "foo"},
}
numAddr := 3
removeDelay := 1 * time.Millisecond
ConfigureBuilder(numAddr, removeDelay)
testCases := []struct {
desc string
actions []action
lastFails bool
delay time.Duration
}{
{
desc: "add then remove",
actions: okActions,
delay: 2 * removeDelay,
},
{
desc: "add then remove but too fast",
actions: okActions,
lastFails: true,
delay: 0,
},
{
desc: "remove one address too many",
actions: append(okActions, action{remove: "qux"}),
lastFails: true,
delay: 2 * removeDelay,
},
{
desc: "remove unknown address",
actions: []action{
{add: "foo"},
{add: "qux"},
{add: "baz"},
{remove: "bar"},
},
lastFails: true,
delay: 2 * removeDelay,
},
{
// This relies on the implementation detail that the first address added
// to the balancer is the standby. The standby cannot be removed.
desc: "remove standby address",
actions: []action{
{add: "foo"},
{add: "qux"},
{add: "baz"},
{remove: "foo"},
},
lastFails: true,
delay: 2 * removeDelay,
},
}
for _, tc := range testCases {
t.Run(tc.desc, func(t *testing.T) {
lbBuilder.testingRestart <- struct{}{}
bootSleep := 2 * removeDelay
if bootSleep == 0 {
bootSleep = 2 * time.Millisecond
}
time.Sleep(bootSleep) // wait for lastRemoval in monitor goroutine to be long enough ago
for i, a := range tc.actions {
if a.add != "" {
AddAddress(a.add)
} else {
if tc.delay > 0 {
time.Sleep(tc.delay)
}
expected := true
if i+1 == len(tc.actions) && tc.lastFails {
expected = false
}
require.Equal(t, expected, RemoveAddress(a.remove), "expected result from removing %q", a.remove)
}
}
})
}
}
type action struct {
add string
remove string
}
type testClientConn struct {
addrUpdates [][]resolver.Address
configUpdates []string
mu sync.Mutex
}
func (tcc *testClientConn) NewAddress(addresses []resolver.Address) {
tcc.mu.Lock()
defer tcc.mu.Unlock()
tcc.addrUpdates = append(tcc.addrUpdates, addresses)
}
func (tcc *testClientConn) NewServiceConfig(serviceConfig string) {
tcc.mu.Lock()
defer tcc.mu.Unlock()
tcc.configUpdates = append(tcc.configUpdates, serviceConfig)
}
func (tcc *testClientConn) AddrUpdates() [][]resolver.Address {
tcc.mu.Lock()
defer tcc.mu.Unlock()
return tcc.addrUpdates
}
func (tcc *testClientConn) ConfigUpdates() []string {
tcc.mu.Lock()
defer tcc.mu.Unlock()
return tcc.configUpdates
}
// configureBuilderTest reconfigures the global builder and pre-populates
// it with addresses. It returns the list of addresses it added.
func configureBuilderTest(numAddrs int) []string {
delay := 1 * time.Millisecond
ConfigureBuilder(numAddrs, delay)
lbBuilder.testingRestart <- struct{}{}
time.Sleep(2 * delay)
var addrs []string
for i := 0; i < numAddrs; i++ {
a := fmt.Sprintf("test.%d", i)
AddAddress(a)
addrs = append(addrs, a)
}
return addrs
}
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