youtubebeat/vendor/github.com/elastic/beats/metricbeat/mb/module/runner.go

98 lines
2.7 KiB
Go

// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package module
import (
"fmt"
"sync"
"github.com/elastic/beats/libbeat/beat"
"github.com/elastic/beats/libbeat/monitoring"
)
var (
moduleList *monitoring.UniqueList
)
func init() {
moduleList = monitoring.NewUniqueList()
monitoring.NewFunc(monitoring.GetNamespace("state").GetRegistry(), "module", moduleList.Report, monitoring.Report)
}
// Runner is a facade for a Wrapper that provides a simple interface
// for starting and stopping a Module.
type Runner interface {
// fmt.Stringer is required here because when used as a cfgfile.Runner
// we need a way to print a threadsafe set of fields since it will likely
// be printed from a concurrent goroutine.
fmt.Stringer
// Start starts the Module. If Start is called more than once, only the
// first will start the Module.
Start()
// Stop stops the Module and waits for module's MetricSets to exit. The
// publisher.Client will be closed by Stop. If Stop is called more than
// once, only the first stop the Module and wait for it to exit.
Stop()
}
// NewRunner returns a Runner facade. The events generated by
// the Module will be published to a new publisher.Client generated from the
// pubClientFactory.
func NewRunner(client beat.Client, mod *Wrapper) Runner {
return &runner{
done: make(chan struct{}),
mod: mod,
client: client,
}
}
type runner struct {
done chan struct{}
wg sync.WaitGroup
startOnce sync.Once
stopOnce sync.Once
mod *Wrapper
client beat.Client
}
func (mr *runner) Start() {
mr.startOnce.Do(func() {
output := mr.mod.Start(mr.done)
mr.wg.Add(1)
moduleList.Add(mr.mod.Name())
go func() {
defer mr.wg.Done()
PublishChannels(mr.client, output)
}()
})
}
func (mr *runner) Stop() {
mr.stopOnce.Do(func() {
close(mr.done)
mr.client.Close()
mr.wg.Wait()
moduleList.Remove(mr.mod.Name())
})
}
func (mr *runner) String() string {
return fmt.Sprintf("%s [metricsets=%d]", mr.mod.Name(), len(mr.mod.metricSets))
}