clair/health/health.go
2016-02-24 16:34:54 -05:00

83 lines
2.5 KiB
Go

// Copyright 2015 clair 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 health defines a standard healthcheck response format and expose
// a function that summarizes registered healthchecks.
package health
import (
"fmt"
"sync"
"github.com/coreos/clair/database"
)
// Status defines a way to know the health status of a service
type Status struct {
// IsEssential determines if the service is essential to the app, which can't
// run in case of a failure
IsEssential bool
// IsHealthy defines whether the service is working or not
IsHealthy bool
// Details gives informations specific to the service
Details interface{}
}
// A Healthchecker function is a method returning the Status of the tested service
type Healthchecker func(database.Datastore) Status
var (
healthcheckersLock sync.Mutex
healthcheckers = make(map[string]Healthchecker)
)
// RegisterHealthchecker registers a Healthchecker function which will be part of Healthchecks
func RegisterHealthchecker(name string, f Healthchecker) {
if name == "" {
panic("Could not register a Healthchecker with an empty name")
}
if f == nil {
panic("Could not register a nil Healthchecker")
}
healthcheckersLock.Lock()
defer healthcheckersLock.Unlock()
if _, alreadyExists := healthcheckers[name]; alreadyExists {
panic(fmt.Sprintf("Healthchecker '%s' is already registered", name))
}
healthcheckers[name] = f
}
// Healthcheck calls every registered Healthchecker and summarize their output
func Healthcheck(datastore database.Datastore) (bool, map[string]interface{}) {
globalHealth := true
statuses := make(map[string]interface{})
for serviceName, serviceChecker := range healthcheckers {
status := serviceChecker(datastore)
globalHealth = globalHealth && (!status.IsEssential || status.IsHealthy)
statuses[serviceName] = struct {
IsHealthy bool
Details interface{} `json:",omitempty"`
}{
IsHealthy: status.IsHealthy,
Details: status.Details,
}
}
return globalHealth, statuses
}