Created
May 19, 2019 16:46
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external-dns controller/controller.go
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/* | |
Copyright 2017 The Kubernetes 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 controller | |
import ( | |
"context" | |
"time" | |
"github.com/prometheus/client_golang/prometheus" | |
log "github.com/sirupsen/logrus" | |
"github.com/kubernetes-incubator/external-dns/plan" | |
"github.com/kubernetes-incubator/external-dns/provider" | |
"github.com/kubernetes-incubator/external-dns/registry" | |
"github.com/kubernetes-incubator/external-dns/source" | |
"github.com/davecgh/go-spew/spew" | |
) | |
var ( | |
registryErrors = prometheus.NewCounter( | |
prometheus.CounterOpts{ | |
Name: "registry_errors_total", | |
Help: "Number of Registry errors.", | |
}, | |
) | |
sourceErrors = prometheus.NewCounter( | |
prometheus.CounterOpts{ | |
Name: "source_errors_total", | |
Help: "Number of Source errors.", | |
}, | |
) | |
sourceEndpointsTotal = prometheus.NewGauge( | |
prometheus.GaugeOpts{ | |
Namespace: "external_dns", | |
Subsystem: "source", | |
Name: "endpoints_total", | |
Help: "Number of Endpoints in all sources", | |
}, | |
) | |
registryEndpointsTotal = prometheus.NewGauge( | |
prometheus.GaugeOpts{ | |
Namespace: "external_dns", | |
Subsystem: "registry", | |
Name: "endpoints_total", | |
Help: "Number of Endpoints in the registry", | |
}, | |
) | |
) | |
func init() { | |
prometheus.MustRegister(registryErrors) | |
prometheus.MustRegister(sourceErrors) | |
prometheus.MustRegister(sourceEndpointsTotal) | |
prometheus.MustRegister(registryEndpointsTotal) | |
} | |
// Controller is responsible for orchestrating the different components. | |
// It works in the following way: | |
// * Ask the DNS provider for current list of endpoints. | |
// * Ask the Source for the desired list of endpoints. | |
// * Take both lists and calculate a Plan to move current towards desired state. | |
// * Tell the DNS provider to apply the changes calucated by the Plan. | |
type Controller struct { | |
Source source.Source | |
Registry registry.Registry | |
// The policy that defines which changes to DNS records are allowed | |
Policy plan.Policy | |
// The interval between individual synchronizations | |
Interval time.Duration | |
} | |
// RunOnce runs a single iteration of a reconciliation loop. | |
func (c *Controller) RunOnce() error { | |
records, err := c.Registry.Records() | |
if err != nil { | |
registryErrors.Inc() | |
return err | |
} | |
registryEndpointsTotal.Set(float64(len(records))) | |
spew.Dump(records) | |
ctx := context.WithValue(context.Background(), provider.RecordsContextKey, records) | |
endpoints, err := c.Source.Endpoints() | |
if err != nil { | |
sourceErrors.Inc() | |
return err | |
} | |
sourceEndpointsTotal.Set(float64(len(endpoints))) | |
spew.Dump(endpoints) | |
plan := &plan.Plan{ | |
Policies: []plan.Policy{c.Policy}, | |
Current: records, | |
Desired: endpoints, | |
} | |
plan = plan.Calculate() | |
spew.Dump(plan) | |
err = c.Registry.ApplyChanges(ctx, plan.Changes) | |
if err != nil { | |
registryErrors.Inc() | |
return err | |
} | |
return nil | |
} | |
// Run runs RunOnce in a loop with a delay until stopChan receives a value. | |
func (c *Controller) Run(stopChan <-chan struct{}) { | |
ticker := time.NewTicker(c.Interval) | |
defer ticker.Stop() | |
for { | |
err := c.RunOnce() | |
if err != nil { | |
log.Error(err) | |
} | |
select { | |
case <-ticker.C: | |
case <-stopChan: | |
log.Info("Terminating main controller loop") | |
return | |
} | |
} | |
} |
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