Maint: rework publicip package

- Use loopstate package
- Loop interface composition
- Return concrete struct from constructors
- Split into more files
- Add publicip/state package

internal/publicip/runner.go

@@ -0,0 +1,101 @@
+package publicip
+
+import (
+	"context"
+	"net"
+	"os"
+
+	"github.com/qdm12/gluetun/internal/constants"
+)
+
+type Runner interface {
+	Run(ctx context.Context, done chan<- struct{})
+}
+
+func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
+	defer close(done)
+
+	crashed := false
+
+	select {
+	case <-l.start:
+	case <-ctx.Done():
+		return
+	}
+
+	for ctx.Err() == nil {
+		getCtx, getCancel := context.WithCancel(ctx)
+		defer getCancel()
+
+		ipCh := make(chan net.IP)
+		errorCh := make(chan error)
+		go func() {
+			ip, err := l.fetcher.FetchPublicIP(getCtx)
+			if err != nil {
+				if getCtx.Err() == nil {
+					errorCh <- err
+				}
+				return
+			}
+			ipCh <- ip
+		}()
+
+		if !crashed {
+			l.running <- constants.Running
+			crashed = false
+		} else {
+			l.backoffTime = defaultBackoffTime
+			l.statusManager.SetStatus(constants.Running)
+		}
+
+		stayHere := true
+		for stayHere {
+			select {
+			case <-ctx.Done():
+				getCancel()
+				close(errorCh)
+				filepath := l.state.GetSettings().IPFilepath
+				l.logger.Info("Removing ip file " + filepath)
+				if err := os.Remove(filepath); err != nil {
+					l.logger.Error(err.Error())
+				}
+				return
+			case <-l.start:
+				getCancel()
+				stayHere = false
+			case <-l.stop:
+				l.logger.Info("stopping")
+				getCancel()
+				<-errorCh
+				l.stopped <- struct{}{}
+			case ip := <-ipCh:
+				getCancel()
+				l.state.SetPublicIP(ip)
+
+				message := "Public IP address is " + ip.String()
+				result, err := Info(ctx, l.client, ip)
+				if err != nil {
+					l.logger.Warn(err.Error())
+				} else {
+					message += " (" + result.Country + ", " + result.Region + ", " + result.City + ")"
+				}
+				l.logger.Info(message)
+
+				filepath := l.state.GetSettings().IPFilepath
+				err = persistPublicIP(filepath, ip.String(), l.puid, l.pgid)
+				if err != nil {
+					l.logger.Error(err.Error())
+				}
+				l.statusManager.SetStatus(constants.Completed)
+			case err := <-errorCh:
+				getCancel()
+				close(ipCh)
+				l.statusManager.SetStatus(constants.Crashed)
+				l.logAndWait(ctx, err)
+				crashed = true
+				stayHere = false
+			}
+		}
+		close(errorCh)
+	}
+}