package models import ( "encoding/json" "io/ioutil" "log" "os" "sync" "time" ) //Node struct type Node struct { Firstseen time.Time `json:"firstseen"` Lastseen time.Time `json:"lastseen"` Statistics interface{} `json:"statistics"` Nodeinfo interface{} `json:"nodeinfo"` Neighbours interface{} `json:"neighbours"` } //Nodes struct: cache DB of Node's structs type Nodes struct { Version int `json:"version"` Timestamp time.Time `json:"timestamp"` List map[string]*Node `json:"nodes"` // the current nodemap sync.Mutex } //NewNodes create Nodes structs (cache DB) func NewNodes() *Nodes { nodes := &Nodes{ Version: 1, List: make(map[string]*Node), } return nodes } //Get a Node by nodeid func (nodes *Nodes) Get(nodeID string) *Node { now := time.Now() nodes.Lock() node, _ := nodes.List[nodeID] if node == nil { node = &Node{ Firstseen: now, } nodes.List[nodeID] = node } nodes.Unlock() node.Lastseen = now return node } //Saver to save the cached DB to json file func (nodes *Nodes) Saver(outputFile string, saveInterval time.Duration) { c := time.Tick(saveInterval) for range c { nodes.save(outputFile) } } func (nodes *Nodes) save(outputFile string) { nodes.Timestamp = time.Now() nodes.Lock() data, err := json.Marshal(nodes) nodes.Unlock() if err != nil { log.Panic(err) } log.Println("saving", len(nodes.List), "nodes") tmpFile := outputFile + ".tmp" err = ioutil.WriteFile(tmpFile, data, 0644) if err != nil { log.Panic(err) } err = os.Rename(tmpFile, outputFile) if err != nil { log.Panic(err) } }