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/*
* Copyright 2019 Intel Corporation, Inc
*
* 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 namegenerator
import (
"encoding/json"
"log"
"strings"
"sync"
"github.com/onap/multicloud-k8s/src/k8splugin/internal/db"
"github.com/docker/engine/pkg/namesgenerator"
pkgerrors "github.com/pkg/errors"
)
const (
storeName = "instanceNames"
tag = "names"
)
var (
nameCache = &cache{}
cacheKeyGlobal = cacheKey{"k8sPluginCacheKey"}
)
type cache struct {
cache map[string]bool
mux sync.Mutex
}
type cacheKey struct {
Key string `json:"key"`
}
func (c cacheKey) String() string {
out, err := json.Marshal(c)
if err != nil {
return ""
}
return string(out)
}
func (c *cache) init() {
// We have either restarted or this is the first time
// that a name is being requested since the service came
// up.
if c.cache == nil {
c.cache = make(map[string]bool)
err := c.readCacheFromDB()
if err != nil {
log.Println("Error Reading from DB: ", err.Error())
return
}
}
}
func (c *cache) isAlreadyUsed(name string) bool {
if _, ok := c.cache[name]; ok {
return true
}
return false
}
func (c *cache) readCacheFromDB() error {
// Read the latest from cache
data, err := db.DBconn.Read(storeName, cacheKeyGlobal, tag)
if err != nil {
log.Println("Error reading name cache from Database: ", err)
return pkgerrors.Wrap(err, "Reading cache from DB")
}
err = db.DBconn.Unmarshal(data, &c.cache)
if err != nil {
log.Println("Error unmarshaling data into cache: ", err)
return pkgerrors.Wrap(err, "Unmarshaling cache from DB")
}
return nil
}
// writeCacheToDB will update the DB with the updated cache
func (c *cache) writeCacheToDB() {
//Update the database as well
err := db.DBconn.Update(storeName, cacheKeyGlobal, tag, c.cache)
if err != nil {
// TODO: Replace with DBconn variable
if strings.Contains(err.Error(), "Error finding master table") {
err = db.DBconn.Create(storeName, cacheKeyGlobal, tag, c.cache)
if err != nil {
log.Println("Error creating the entry in DB. Will try later...")
return
}
} else {
log.Println("Error updating DB: ", err.Error())
return
}
}
}
func (c *cache) generateName() string {
c.mux.Lock()
defer c.mux.Unlock()
c.init()
for {
//Call moby package here to generate name
name := namesgenerator.GetRandomName(0)
if c.isAlreadyUsed(name) {
// Generate another name
log.Printf("Name %s already used", name)
continue
}
c.cache[name] = true
// Update the cache and db
c.writeCacheToDB()
return name
}
}
// Generate returns an autogenerated name
func Generate() string {
return nameCache.generateName()
}
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