forked from flynn/flynn
/
discoverd.go
139 lines (123 loc) · 2.84 KB
/
discoverd.go
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package main
import (
"errors"
"fmt"
"os"
"sync"
"sync/atomic"
"github.com/flynn/flynn/discoverd/client"
"github.com/flynn/flynn/host/logmux"
"github.com/flynn/flynn/host/types"
"github.com/flynn/flynn/pkg/shutdown"
)
func NewDiscoverdManager(backend Backend, mux *logmux.Mux, hostID, publishAddr string, tags map[string]string) *DiscoverdManager {
d := &DiscoverdManager{
backend: backend,
mux: mux,
inst: &discoverd.Instance{
Addr: publishAddr,
Meta: map[string]string{"id": hostID},
},
}
for k, v := range tags {
d.inst.Meta[host.TagPrefix+k] = v
}
d.local.Store(false)
return d
}
type DiscoverdManager struct {
backend Backend
mux *logmux.Mux
inst *discoverd.Instance
mtx sync.Mutex
hb discoverd.Heartbeater
local atomic.Value // bool
}
func (d *DiscoverdManager) Close() error {
d.mtx.Lock()
defer d.mtx.Unlock()
if d.hb != nil {
// explicitly indicate in the metadata that the host is
// shutting down so that the scheduler removes the host
// immediately (rather than treating it as unhealthy for a
// short time)
d.inst.Meta["shutdown"] = "true"
d.hb.SetMeta(d.inst.Meta)
err := d.hb.Close()
d.hb = nil
return err
}
return nil
}
func (d *DiscoverdManager) localConnected() bool {
return d.local.Load().(bool)
}
func (d *DiscoverdManager) heartbeat(url string) error {
disc := discoverd.NewClientWithURL(url)
d.mtx.Lock()
defer d.mtx.Unlock()
if d.hb != nil {
d.hb.SetClient(disc)
return nil
}
hb, err := disc.AddServiceAndRegisterInstance("flynn-host", d.inst)
if err != nil {
return err
}
d.hb = hb
return nil
}
func (d *DiscoverdManager) ConnectLocal(url string) error {
if d.localConnected() {
return errors.New("host: discoverd is already configured")
}
if err := d.heartbeat(url); err != nil {
return err
}
d.local.Store(true)
d.backend.SetDefaultEnv("DISCOVERD", url)
os.Setenv("DISCOVERD", url)
discoverd.DefaultClient = discoverd.NewClient()
go func() {
if err := d.mux.StreamToAggregators(discoverd.NewClientWithURL(url).Service("logaggregator")); err != nil {
shutdown.Fatal(err)
}
}()
return nil
}
func (d *DiscoverdManager) ConnectPeer(ips []string) error {
if d.localConnected() {
return nil
}
if len(ips) == 0 {
return errors.New("host: no discoverd peers available")
}
var err error
for _, ip := range ips {
// TODO: log attempt
url := fmt.Sprintf("http://%s:1111", ip)
if err = d.heartbeat(url); err != nil {
// TODO: log error
continue
}
break
}
return err
}
func (d *DiscoverdManager) UpdateTags(tags map[string]string) error {
d.mtx.Lock()
defer d.mtx.Unlock()
for k, v := range tags {
name := host.TagPrefix + k
// treat empty tags as ones to delete
if v == "" {
delete(d.inst.Meta, name)
continue
}
d.inst.Meta[name] = v
}
if d.hb == nil {
return nil
}
return d.hb.SetMeta(d.inst.Meta)
}