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Remove HostPoolHostPolicy from gocql package
HostPoolHostPolicy was moved to a separate package, and users don't need to download dependency if they aren't using it. patch by Oleksandr Luzhniy; reviewed by João Reis, Stanislav Bychkov, James Hartig, for CASSGO-21
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5 files changed

+210
-186
lines changed

5 files changed

+210
-186
lines changed

‎CHANGELOG.md‎

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@@ -27,6 +27,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
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- Keep nil slices in MapScan (CASSGO-44)
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- Improve error messages for marshalling (CASSGO-38)
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- Remove HostPoolHostPolicy from gocql package (CASSGO-21)
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### Fixed
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- Retry policy now takes into account query idempotency (CASSGO-27)

‎hostpool/hostpool.go‎

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@@ -0,0 +1,150 @@
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package hostpool
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import (
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"sync"
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"github.com/hailocab/go-hostpool"
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"github.com/gocql/gocql"
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)
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// HostPoolHostPolicy is a host policy which uses the bitly/go-hostpool library
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// to distribute queries between hosts and prevent sending queries to
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// unresponsive hosts. When creating the host pool that is passed to the policy
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// use an empty slice of hosts as the hostpool will be populated later by gocql.
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// See below for examples of usage:
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//
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// // Create host selection policy using a simple host pool
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// cluster.PoolConfig.HostSelectionPolicy = HostPoolHostPolicy(hostpool.New(nil))
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//
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// // Create host selection policy using an epsilon greedy pool
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// cluster.PoolConfig.HostSelectionPolicy = HostPoolHostPolicy(
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// hostpool.NewEpsilonGreedy(nil, 0, &hostpool.LinearEpsilonValueCalculator{}),
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// )
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func HostPoolHostPolicy(hp hostpool.HostPool) *hostPoolHostPolicy {
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return &hostPoolHostPolicy{hostMap: map[string]*gocql.HostInfo{}, hp: hp}
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}
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type hostPoolHostPolicy struct {
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hp hostpool.HostPool
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mu sync.RWMutex
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hostMap map[string]*gocql.HostInfo
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}
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func (r *hostPoolHostPolicy) Init(*gocql.Session) {}
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func (r *hostPoolHostPolicy) KeyspaceChanged(gocql.KeyspaceUpdateEvent) {}
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func (r *hostPoolHostPolicy) SetPartitioner(string) {}
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func (r *hostPoolHostPolicy) IsLocal(*gocql.HostInfo) bool { return true }
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func (r *hostPoolHostPolicy) SetHosts(hosts []*gocql.HostInfo) {
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peers := make([]string, len(hosts))
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hostMap := make(map[string]*gocql.HostInfo, len(hosts))
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for i, host := range hosts {
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ip := host.ConnectAddress().String()
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peers[i] = ip
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hostMap[ip] = host
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}
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r.mu.Lock()
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r.hp.SetHosts(peers)
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r.hostMap = hostMap
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r.mu.Unlock()
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}
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func (r *hostPoolHostPolicy) AddHost(host *gocql.HostInfo) {
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ip := host.ConnectAddress().String()
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r.mu.Lock()
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defer r.mu.Unlock()
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// If the host addr is present and isn't nil return
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if h, ok := r.hostMap[ip]; ok && h != nil {
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return
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}
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// otherwise, add the host to the map
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r.hostMap[ip] = host
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// and construct a new peer list to give to the HostPool
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hosts := make([]string, 0, len(r.hostMap))
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for addr := range r.hostMap {
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hosts = append(hosts, addr)
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}
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r.hp.SetHosts(hosts)
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}
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func (r *hostPoolHostPolicy) RemoveHost(host *gocql.HostInfo) {
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ip := host.ConnectAddress().String()
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r.mu.Lock()
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defer r.mu.Unlock()
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if _, ok := r.hostMap[ip]; !ok {
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return
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}
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delete(r.hostMap, ip)
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hosts := make([]string, 0, len(r.hostMap))
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for _, host := range r.hostMap {
89+
hosts = append(hosts, host.ConnectAddress().String())
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}
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r.hp.SetHosts(hosts)
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}
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func (r *hostPoolHostPolicy) HostUp(host *gocql.HostInfo) {
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r.AddHost(host)
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}
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func (r *hostPoolHostPolicy) HostDown(host *gocql.HostInfo) {
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r.RemoveHost(host)
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}
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func (r *hostPoolHostPolicy) Pick(qry gocql.ExecutableQuery) gocql.NextHost {
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return func() gocql.SelectedHost {
105+
r.mu.RLock()
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defer r.mu.RUnlock()
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if len(r.hostMap) == 0 {
109+
return nil
110+
}
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hostR := r.hp.Get()
113+
host, ok := r.hostMap[hostR.Host()]
114+
if !ok {
115+
return nil
116+
}
117+
118+
return selectedHostPoolHost{
119+
policy: r,
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info: host,
121+
hostR: hostR,
122+
}
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}
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}
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// selectedHostPoolHost is a host returned by the hostPoolHostPolicy and
127+
// implements the SelectedHost interface
128+
type selectedHostPoolHost struct {
129+
policy *hostPoolHostPolicy
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info *gocql.HostInfo
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hostR hostpool.HostPoolResponse
132+
}
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func (host selectedHostPoolHost) Info() *gocql.HostInfo {
135+
return host.info
136+
}
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func (host selectedHostPoolHost) Mark(err error) {
139+
ip := host.info.ConnectAddress().String()
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141+
host.policy.mu.RLock()
142+
defer host.policy.mu.RUnlock()
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if _, ok := host.policy.hostMap[ip]; !ok {
145+
// host was removed between pick and mark
146+
return
147+
}
148+
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host.hostR.Mark(err)
150+
}

‎hostpool/hostpool_test.go‎

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@@ -0,0 +1,57 @@
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package hostpool
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import (
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"fmt"
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"net"
6+
"testing"
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"github.com/hailocab/go-hostpool"
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10+
"github.com/gocql/gocql"
11+
)
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func TestHostPolicy_HostPool(t *testing.T) {
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policy := HostPoolHostPolicy(hostpool.New(nil))
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16+
//hosts := []*gocql.HostInfo{
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// {hostId: "0", connectAddress: net.IPv4(10, 0, 0, 0)},
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// {hostId: "1", connectAddress: net.IPv4(10, 0, 0, 1)},
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//}
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firstHost := &gocql.HostInfo{}
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firstHost.SetHostID("0")
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firstHost.SetConnectAddress(net.IPv4(10, 0, 0, 0))
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secHost := &gocql.HostInfo{}
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secHost.SetHostID("1")
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secHost.SetConnectAddress(net.IPv4(10, 0, 0, 1))
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hosts := []*gocql.HostInfo{firstHost, secHost}
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// Using set host to control the ordering of the hosts as calling "AddHost" iterates the map
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// which will result in an unpredictable ordering
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policy.SetHosts(hosts)
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// the first host selected is actually at [1], but this is ok for RR
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// interleaved iteration should always increment the host
33+
iter := policy.Pick(nil)
34+
actualA := iter()
35+
if actualA.Info().HostID() != "0" {
36+
t.Errorf("Expected hosts[0] but was hosts[%s]", actualA.Info().HostID())
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}
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actualA.Mark(nil)
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actualB := iter()
41+
if actualB.Info().HostID() != "1" {
42+
t.Errorf("Expected hosts[1] but was hosts[%s]", actualB.Info().HostID())
43+
}
44+
actualB.Mark(fmt.Errorf("error"))
45+
46+
actualC := iter()
47+
if actualC.Info().HostID() != "0" {
48+
t.Errorf("Expected hosts[0] but was hosts[%s]", actualC.Info().HostID())
49+
}
50+
actualC.Mark(nil)
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actualD := iter()
53+
if actualD.Info().HostID() != "0" {
54+
t.Errorf("Expected hosts[0] but was hosts[%s]", actualD.Info().HostID())
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}
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actualD.Mark(nil)
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}

‎policies.go‎

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Original file line numberDiff line numberDiff line change
@@ -36,8 +36,6 @@ import (
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"sync"
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"sync/atomic"
3838
"time"
39-
40-
"github.com/hailocab/go-hostpool"
4139
)
4240

4341
// cowHostList implements a copy on write host list, its equivalent type is []*HostInfo
@@ -690,147 +688,6 @@ func (t *tokenAwareHostPolicy) Pick(qry ExecutableQuery) NextHost {
690688
}
691689
}
692690

693-
// HostPoolHostPolicy is a host policy which uses the bitly/go-hostpool library
694-
// to distribute queries between hosts and prevent sending queries to
695-
// unresponsive hosts. When creating the host pool that is passed to the policy
696-
// use an empty slice of hosts as the hostpool will be populated later by gocql.
697-
// See below for examples of usage:
698-
//
699-
// // Create host selection policy using a simple host pool
700-
// cluster.PoolConfig.HostSelectionPolicy = HostPoolHostPolicy(hostpool.New(nil))
701-
//
702-
// // Create host selection policy using an epsilon greedy pool
703-
// cluster.PoolConfig.HostSelectionPolicy = HostPoolHostPolicy(
704-
// hostpool.NewEpsilonGreedy(nil, 0, &hostpool.LinearEpsilonValueCalculator{}),
705-
// )
706-
func HostPoolHostPolicy(hp hostpool.HostPool) HostSelectionPolicy {
707-
return &hostPoolHostPolicy{hostMap: map[string]*HostInfo{}, hp: hp}
708-
}
709-
710-
type hostPoolHostPolicy struct {
711-
hp hostpool.HostPool
712-
mu sync.RWMutex
713-
hostMap map[string]*HostInfo
714-
}
715-
716-
func (r *hostPoolHostPolicy) Init(*Session) {}
717-
func (r *hostPoolHostPolicy) KeyspaceChanged(KeyspaceUpdateEvent) {}
718-
func (r *hostPoolHostPolicy) SetPartitioner(string) {}
719-
func (r *hostPoolHostPolicy) IsLocal(*HostInfo) bool { return true }
720-
721-
func (r *hostPoolHostPolicy) SetHosts(hosts []*HostInfo) {
722-
peers := make([]string, len(hosts))
723-
hostMap := make(map[string]*HostInfo, len(hosts))
724-
725-
for i, host := range hosts {
726-
ip := host.ConnectAddress().String()
727-
peers[i] = ip
728-
hostMap[ip] = host
729-
}
730-
731-
r.mu.Lock()
732-
r.hp.SetHosts(peers)
733-
r.hostMap = hostMap
734-
r.mu.Unlock()
735-
}
736-
737-
func (r *hostPoolHostPolicy) AddHost(host *HostInfo) {
738-
ip := host.ConnectAddress().String()
739-
740-
r.mu.Lock()
741-
defer r.mu.Unlock()
742-
743-
// If the host addr is present and isn't nil return
744-
if h, ok := r.hostMap[ip]; ok && h != nil {
745-
return
746-
}
747-
// otherwise, add the host to the map
748-
r.hostMap[ip] = host
749-
// and construct a new peer list to give to the HostPool
750-
hosts := make([]string, 0, len(r.hostMap))
751-
for addr := range r.hostMap {
752-
hosts = append(hosts, addr)
753-
}
754-
755-
r.hp.SetHosts(hosts)
756-
}
757-
758-
func (r *hostPoolHostPolicy) RemoveHost(host *HostInfo) {
759-
ip := host.ConnectAddress().String()
760-
761-
r.mu.Lock()
762-
defer r.mu.Unlock()
763-
764-
if _, ok := r.hostMap[ip]; !ok {
765-
return
766-
}
767-
768-
delete(r.hostMap, ip)
769-
hosts := make([]string, 0, len(r.hostMap))
770-
for _, host := range r.hostMap {
771-
hosts = append(hosts, host.ConnectAddress().String())
772-
}
773-
774-
r.hp.SetHosts(hosts)
775-
}
776-
777-
func (r *hostPoolHostPolicy) HostUp(host *HostInfo) {
778-
r.AddHost(host)
779-
}
780-
781-
func (r *hostPoolHostPolicy) HostDown(host *HostInfo) {
782-
r.RemoveHost(host)
783-
}
784-
785-
func (r *hostPoolHostPolicy) Pick(qry ExecutableQuery) NextHost {
786-
return func() SelectedHost {
787-
r.mu.RLock()
788-
defer r.mu.RUnlock()
789-
790-
if len(r.hostMap) == 0 {
791-
return nil
792-
}
793-
794-
hostR := r.hp.Get()
795-
host, ok := r.hostMap[hostR.Host()]
796-
if !ok {
797-
return nil
798-
}
799-
800-
return selectedHostPoolHost{
801-
policy: r,
802-
info: host,
803-
hostR: hostR,
804-
}
805-
}
806-
}
807-
808-
// selectedHostPoolHost is a host returned by the hostPoolHostPolicy and
809-
// implements the SelectedHost interface
810-
type selectedHostPoolHost struct {
811-
policy *hostPoolHostPolicy
812-
info *HostInfo
813-
hostR hostpool.HostPoolResponse
814-
}
815-
816-
func (host selectedHostPoolHost) Info() *HostInfo {
817-
return host.info
818-
}
819-
820-
func (host selectedHostPoolHost) Mark(err error) {
821-
ip := host.info.ConnectAddress().String()
822-
823-
host.policy.mu.RLock()
824-
defer host.policy.mu.RUnlock()
825-
826-
if _, ok := host.policy.hostMap[ip]; !ok {
827-
// host was removed between pick and mark
828-
return
829-
}
830-
831-
host.hostR.Mark(err)
832-
}
833-
834691
type dcAwareRR struct {
835692
local string
836693
localHosts cowHostList

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