prometheus/retrieval/discovery/marathon.go

106 lines
2.8 KiB
Go

// Copyright 2015 The Prometheus Authors
// Licensed 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 discovery
import (
"time"
"github.com/prometheus/common/log"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/retrieval/discovery/marathon"
)
// MarathonDiscovery provides service discovery based on a Marathon instance.
type MarathonDiscovery struct {
servers []string
refreshInterval time.Duration
done chan struct{}
lastRefresh map[string]*config.TargetGroup
client marathon.AppListClient
}
// NewMarathonDiscovery creates a new Marathon based discovery.
func NewMarathonDiscovery(conf *config.MarathonSDConfig) *MarathonDiscovery {
return &MarathonDiscovery{
servers: conf.Servers,
refreshInterval: time.Duration(conf.RefreshInterval),
done: make(chan struct{}),
client: marathon.FetchMarathonApps,
}
}
// Sources implements the TargetProvider interface.
func (md *MarathonDiscovery) Sources() []string {
var sources []string
tgroups, err := md.fetchTargetGroups()
if err == nil {
for source := range tgroups {
sources = append(sources, source)
}
}
return sources
}
// Run implements the TargetProvider interface.
func (md *MarathonDiscovery) Run(ch chan<- config.TargetGroup, done <-chan struct{}) {
defer close(ch)
for {
select {
case <-done:
return
case <-time.After(md.refreshInterval):
err := md.updateServices(ch)
if err != nil {
log.Errorf("Error while updating services: %s", err)
}
}
}
}
func (md *MarathonDiscovery) updateServices(ch chan<- config.TargetGroup) error {
targetMap, err := md.fetchTargetGroups()
if err != nil {
return err
}
// Update services which are still present
for _, tg := range targetMap {
ch <- *tg
}
// Remove services which did disappear
for source := range md.lastRefresh {
_, ok := targetMap[source]
if !ok {
log.Debugf("Removing group for %s", source)
ch <- config.TargetGroup{Source: source}
}
}
md.lastRefresh = targetMap
return nil
}
func (md *MarathonDiscovery) fetchTargetGroups() (map[string]*config.TargetGroup, error) {
url := marathon.RandomAppsURL(md.servers)
apps, err := md.client(url)
if err != nil {
return nil, err
}
groups := marathon.AppsToTargetGroups(apps)
return groups, nil
}