Version 1.0.1 with server

Dockerfile

@@ -0,0 +1,60 @@
+# Accept the Go version for the image to be set as a build argument.
+# Default to Go 1.11
+ARG GO_VERSION=1.11
+
+# First stage: build the executable.
+FROM golang:${GO_VERSION}-alpine AS builder
+
+# Create the user and group files that will be used in the running container to
+# run the process as an unprivileged user.
+# RUN mkdir /user && \
+#     echo 'nobody:x:65534:65534:nobody:/:' > /user/passwd && \
+#     echo 'nobody:x:65534:' > /user/group
+
+# Install the Certificate-Authority certificates for the app to be able to make
+# calls to HTTPS endpoints.
+# Git is required for fetching the dependencies.
+# libcap might be needed in the future for setcap
+RUN apk add --no-cache ca-certificates git
+
+# Set the working directory outside $GOPATH to enable the support for modules.
+WORKDIR /src
+
+# Fetch dependencies first; they are less susceptible to change on every build
+# and will therefore be cached for speeding up the next build
+COPY ./go.mod ./go.sum ./
+RUN go mod download
+
+# Import the code from the context.
+COPY ./ ./
+
+# Build the executable to `/app`. Mark the build as statically linked.
+RUN CGO_ENABLED=0 go build \
+    -installsuffix 'static' \
+    -o /app .
+
+# Add ping privileges
+# RUN setcap cap_net_raw+ep /app
+
+# Final stage: the running container.
+FROM scratch AS final
+
+# Import the user and group files from the first stage.
+# COPY --from=builder /user/group /user/passwd /etc/
+
+# Import the Certificate-Authority certificates for enabling HTTPS.
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+
+# Import the compiled executable from the first stage.
+COPY --from=builder /app /app
+
+# Declare the port on which the webserver will be exposed.
+# As we're going to run the executable as an unprivileged user, we can't bind
+# to ports below 1024.
+EXPOSE 8080
+
+# Perform any further action as an unprivileged user.
+# USER nobody:nobody
+
+# Run the compiled binary.
+ENTRYPOINT ["/app"]

Makefile

@@ -1,5 +1,8 @@
 build:
 	CGO_ENABLED=0 go build -ldflags="-s -w" -o pingish
 
+docker-build:
+	docker build -t balkian/pingish .
+
 run: build
 	./pingish -c 10 -host www.google.es

README.md

@@ -5,6 +5,20 @@ Just copy the binary to the container, and problem solved.
 
 The binary has to be built with `CGO_ENABLED=0` to avoid problems with alpine-based images.
 
+Example of use:
+
+```
+pingish www.google.es
+```
+
+# Server
+
+You can start a server that will accept requests on `/ping?host=<target>`, using the `--server` flag. e.g.
+
+```
+pingish --server
+```
+
 # TROUBLESHOOTING
 
 To run it as a normal user in ubuntu, you might need to configure your host first: `sudo sysctl -w net.ipv4.ping_group_range="0   2147483647"` 

main.go

@@ -1,23 +1,81 @@
 package main
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
+	"log"
 	"net"
+	"net/http"
 	"os"
+	"strconv"
+	"strings"
+	"sync"
 	"time"
 
 	"github.com/tatsushid/go-fastping"
 )
 
-func main() {
-	name := flag.String("host", "www.google.es", "Hostname to ping")
-	count := flag.Int("c", 3, "Number of times to wait for the ")
-	flag.Parse()
+type Response struct {
+	Host string
+	Up   bool
+	RTT  []time.Duration `json:"RTT,omitempty"`
+}
+
+var PING_COUNT = 1
+
+func homeHandler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprint(w, "<h1>Ping a hostname</h1>"+
+		"<form action=\"/ping/\" method=\"GET\">"+
+		"<input type=\"text\"  name=\"host\"><br>"+
+		"<input type=\"submit\" value=\"Ping\">"+
+		"</form>")
+	return
+}
+
+func pingHandler(w http.ResponseWriter, r *http.Request) {
+	name := r.URL.Query().Get("host")
+	if name == "" {
+		tokens := strings.Split(r.URL.Path, "/")
+		if len(tokens) < 3 || tokens[2] == "" {
+			http.Error(w, "You have to specify a hostname to ping", http.StatusBadRequest)
+			return
+		}
+		name = tokens[2]
+	}
+	times := PING_COUNT
+	count := r.URL.Query().Get("count")
+	fmt.Printf("Requested %s %s times\n", name, count)
+
+	if count != "" {
+		if counts, err := strconv.Atoi(count); err == nil {
+			times = counts
+		}
+	}
+
+	up, rtt, err := CheckHost(name, times)
+
+	response := Response{Host: name, Up: up, RTT: rtt}
+	js, err := json.Marshal(response)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if !up {
+		http.Error(w, string(js), http.StatusNotFound)
+		return
+	}
+	w.Write(js)
 
-	adds, err := net.LookupHost(*name)
+}
+
+func CheckHost(name string, times int) (bool, []time.Duration, error) {
+	fmt.Printf("Checking %s\n", name)
+	adds, err := net.LookupHost(name)
 	if err != nil {
-		panic(err)
+		return false, nil, err
 	}
 	fmt.Println("List of addresses:")
 	for _, add := range adds {
@@ -25,21 +83,56 @@ func main() {
 	}
 
 	p := fastping.NewPinger()
-	ra, err := net.ResolveIPAddr("ip4:icmp", *name)
+	ra, err := net.ResolveIPAddr("ip4:icmp", name)
 	if err != nil {
-		fmt.Println(err)
-		os.Exit(1)
+		return false, nil, err
 	}
+	rtttimes := make([]time.Duration, 0)
+	recv := make(chan time.Duration)
 	p.AddIPAddr(ra)
 	p.OnRecv = func(addr *net.IPAddr, rtt time.Duration) {
 		fmt.Printf("IP Addr: %s receive, RTT: %v\n", addr.String(), rtt)
+		recv <- rtt
 	}
-	for i := 0; i < *count; i++ {
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		// Do work
+		for t := range recv {
+			rtttimes = append(rtttimes, t)
+			fmt.Printf("Ping %s: %s\n", name, t)
+		}
+		wg.Done()
+	}()
+
+	for i := 0; i < times; i++ {
 		err = p.Run()
 		if err != nil {
 			fmt.Println(err)
 		}
 	}
+	close(recv)
+	wg.Wait()
 	fmt.Println("finished")
+	return len(rtttimes) > 0, rtttimes, nil
+}
 
+func main() {
+	name := flag.String("host", "www.google.es", "Hostname to ping")
+	count := flag.Int("c", 3, "Number of ping attempts")
+	serve := flag.Bool("server", false, "Start the http server")
+	address := flag.String("address", ":8080", "Host and port to start the http server on")
+	flag.Parse()
+
+	if !*serve {
+		_, _, err := CheckHost(*name, *count)
+		if err == nil {
+			fmt.Printf("could not find host %s: %s\n", *name, err)
+			os.Exit(1)
+		}
+		os.Exit(0)
+	}
+	http.HandleFunc("/", homeHandler)
+	http.HandleFunc("/ping/", pingHandler)
+	log.Fatal(http.ListenAndServe(*address, nil))
 }