Fantom-foundation/go-lachesis

package upgnotifier

import (
    "fmt"
    "math/big"
    "sync"
    "time"

    "github.com/Fantom-foundation/go-lachesis/logger"
    "github.com/Fantom-foundation/go-lachesis/version"
)

type Reader interface {
    GetNetworkVersion() *big.Int
    GetNonSupportedUpgrade() *big.Int
}

type Logger struct {
    logger.Instance
    reader Reader
    done   chan struct{}
    wg     sync.WaitGroup
}

func New(reader Reader) *Logger {
    return &Logger{
        reader:   reader,
        done:     make(chan struct{}),
        Instance: logger.MakeInstance(),
    }
}

func (l *Logger) Start() {
    l.wg.Add(1)
    go func() {
        defer l.wg.Done()
        ticker := time.NewTicker(5 * time.Second)
        defer ticker.Stop()
        for {
            select {
            case <-ticker.C:
                if l.reader.GetNetworkVersion().Cmp(version.AsBigInt()) > 0 {
                    l.Log.Warn(fmt.Sprintf("Network upgrade %s was activated. Current node version is %s. "+
                        "Please upgrade your node and re-sync the chain data.", version.BigToString(l.reader.GetNetworkVersion()), version.AsString()))
                } else if l.reader.GetNonSupportedUpgrade().Sign() > 0 {
                    l.Log.Warn(fmt.Sprintf("Node's state is dirty because node was upgraded after the network upgrade %s was activated. "+
                        "Please re-sync the chain data to continue.", version.BigToString(l.reader.GetNonSupportedUpgrade())))
                }
            case <-l.done:
                return
            }
        }
    }()
}

func (l *Logger) Stop() {
    close(l.done)
    l.wg.Wait()
}