112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
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package client
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import (
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"math/rand"
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"net"
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"sort"
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"strings"
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"sync"
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)
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// serverlist is a prioritized randomized list of nomad servers. Users should
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// call all() to retrieve the full list, followed by failed(e) on each endpoint
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// that's failed and good(e) when a valid endpoint is found.
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type serverlist struct {
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e endpoints
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mu sync.RWMutex
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}
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func newServerList() *serverlist {
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return &serverlist{}
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}
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// set the server list to a new list. The new list will be shuffled and sorted
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// by priority.
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func (s *serverlist) set(in endpoints) {
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s.mu.Lock()
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s.e = in
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s.mu.Unlock()
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}
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// all returns a copy of the full server list, shuffled and then sorted by
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// priority
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func (s *serverlist) all() endpoints {
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s.mu.RLock()
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out := make(endpoints, len(s.e))
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copy(out, s.e)
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s.mu.RUnlock()
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// Randomize the order
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for i, j := range rand.Perm(len(out)) {
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out[i], out[j] = out[j], out[i]
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}
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// Sort by priority
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sort.Sort(out)
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return out
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}
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// failed endpoint will be deprioritized if its still in the list.
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func (s *serverlist) failed(e *endpoint) {
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s.mu.Lock()
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defer s.mu.Unlock()
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for _, cur := range s.e {
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if cur.equal(e) {
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cur.priority++
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return
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}
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}
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}
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// good endpoint will get promoted to the highest priority if it's still in the
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// list.
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func (s *serverlist) good(e *endpoint) {
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s.mu.Lock()
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defer s.mu.Unlock()
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for _, cur := range s.e {
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if cur.equal(e) {
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cur.priority = 0
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return
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}
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}
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}
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func (e endpoints) Len() int {
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return len(e)
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}
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func (e endpoints) Less(i int, j int) bool {
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// Sort only by priority as endpoints should be shuffled and ordered
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// only by priority
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return e[i].priority < e[j].priority
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}
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func (e endpoints) Swap(i int, j int) {
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e[i], e[j] = e[j], e[i]
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}
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type endpoints []*endpoint
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func (e endpoints) String() string {
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names := make([]string, 0, len(e))
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for _, endpoint := range e {
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names = append(names, endpoint.name)
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}
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return strings.Join(names, ",")
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}
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type endpoint struct {
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name string
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addr net.Addr
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// 0 being the highest priority
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priority int
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}
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// equal returns true if the name and addr match between two endpoints.
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// Priority is ignored because the same endpoint may be added by discovery and
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// heartbeating with different priorities.
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func (e *endpoint) equal(o *endpoint) bool {
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return e.name == o.name && e.addr == o.addr
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}
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