add a ping service (#372)

* add a ping service

* add examples and public api file

* add minecraft server ping

ping/handler/ping.go

@@ -0,0 +1,120 @@
+package handler
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/url"
+
+	"github.com/go-ping/ping"
+	"github.com/micro/micro/v3/service/errors"
+	"github.com/micro/micro/v3/service/logger"
+	pb "github.com/micro/services/ping/proto"
+)
+
+type Ping struct{}
+
+func (p *Ping) Ip(ctx context.Context, req *pb.IpRequest, rsp *pb.IpResponse) error {
+	if len(req.Address) == 0 {
+		return errors.BadRequest("ping.ip", "missing address")
+	}
+
+	pinger, err := ping.NewPinger(req.Address)
+	if err != nil {
+		rsp.Status = err.Error()
+		return nil
+	}
+
+	pinger.Count = 4
+	pinger.SetPrivileged(true)
+	err = pinger.Run() // Blocks until finished.
+	if err != nil {
+		rsp.Status = err.Error()
+		return nil
+	}
+
+	pinger.Stop()
+	stats := pinger.Statistics()
+
+	rsp.Status = "OK"
+	rsp.Latency = fmt.Sprintf("%v", stats.AvgRtt)
+
+	return nil
+}
+
+func (p *Ping) Url(ctx context.Context, req *pb.UrlRequest, rsp *pb.UrlResponse) error {
+	if len(req.Address) == 0 {
+		return errors.BadRequest("ping.url", "missing address")
+	}
+
+	u, err := url.Parse(req.Address)
+	if err != nil {
+		return errors.BadRequest("ping.url", "failed to parse url: %v", err)
+	}
+
+	if u.Scheme == "" {
+		u.Scheme = "https"
+	}
+
+	if req.Method == "" {
+		req.Method = "GET"
+	}
+
+	logger.Infof("Calling %s %s", req.Method, u.String())
+
+	hreq, err := http.NewRequest(req.Method, u.String(), nil)
+	if err != nil {
+		return errors.InternalServerError("ping.url", "failed to make request: %v", err)
+	}
+
+	resp, err := http.DefaultClient.Do(hreq)
+	if err != nil {
+		return errors.InternalServerError("ping.url", "failed to call %v: %v", req.Address, err)
+	}
+	defer resp.Body.Close()
+
+	// read body
+	ioutil.ReadAll(resp.Body)
+	// set status
+	rsp.Status = resp.Status
+	rsp.Code = int32(resp.StatusCode)
+
+	return nil
+}
+
+func (p *Ping) Tcp(ctx context.Context, req *pb.TcpRequest, rsp *pb.TcpResponse) error {
+	if len(req.Address) == 0 {
+		return errors.BadRequest("ping.tcp", "missing address")
+	}
+
+	c, err := net.Dial("tcp", req.Address)
+	if err != nil {
+		rsp.Status = err.Error()
+		return nil
+	}
+	defer c.Close()
+
+	// if no data being sent then just return
+	if len(req.Data) == 0 {
+		rsp.Status = "OK"
+		return nil
+	}
+
+	// write data to the connection
+	fmt.Fprint(c, req.Data)
+
+	// wait for a response
+	data, err := bufio.NewReader(c).ReadString('\n')
+	if err != nil {
+		rsp.Status = err.Error()
+		return nil
+	}
+
+	rsp.Status = "OK"
+	rsp.Data = data
+
+	return nil
+}