open-nomad/command/agent/consul/check.go
2016-08-24 01:33:44 +03:00

92 lines
2 KiB
Go

package consul
import (
"log"
"sync"
"time"
"github.com/hashicorp/consul/lib"
cstructs "github.com/hashicorp/nomad/client/driver/structs"
)
// CheckRunner runs a given check in a specific interval and update a
// corresponding Consul TTL check
type CheckRunner struct {
check Check
runCheck func(Check)
logger *log.Logger
stop bool
stopCh chan struct{}
stopLock sync.Mutex
started bool
startedLock sync.Mutex
}
// NewCheckRunner configures and returns a CheckRunner
func NewCheckRunner(check Check, runCheck func(Check), logger *log.Logger) *CheckRunner {
cr := CheckRunner{
check: check,
runCheck: runCheck,
logger: logger,
stopCh: make(chan struct{}),
}
return &cr
}
// Start is used to start the check. The check runs until stop is called
func (r *CheckRunner) Start() {
r.startedLock.Lock()
defer r.startedLock.Unlock()
if r.started {
return
}
r.stopLock.Lock()
defer r.stopLock.Unlock()
go r.run()
r.started = true
}
// Started returns if the check runner has started running
func (r *CheckRunner) Started() bool {
r.startedLock.Lock()
defer r.startedLock.Unlock()
return r.started
}
// Stop is used to stop the check.
func (r *CheckRunner) Stop() {
r.stopLock.Lock()
defer r.stopLock.Unlock()
if !r.stop {
r.stop = true
close(r.stopCh)
}
}
// run is invoked by a goroutine to run until Stop() is called
func (r *CheckRunner) run() {
// Get the randomized initial pause time
initialPauseTime := lib.RandomStagger(r.check.Interval())
r.logger.Printf("[DEBUG] agent: pausing %v before first invocation of %s", initialPauseTime, r.check.ID())
next := time.NewTimer(initialPauseTime)
for {
select {
case <-next.C:
r.runCheck(r.check)
next.Reset(r.check.Interval())
case <-r.stopCh:
next.Stop()
return
}
}
}
// Check is an interface which check providers can implement for Nomad to run
type Check interface {
Run() *cstructs.CheckResult
ID() string
Interval() time.Duration
Timeout() time.Duration
}