describe usage in script

.github/workflows/go.yml

@@ -9,6 +9,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
 
     - name: Set up Go
       uses: actions/setup-go@v2

.goreleaser.yaml

@@ -14,6 +14,7 @@ builds:
       - linux
       - windows
       - darwin
+    mod_timestamp: "{{ .CommitTimestamp }}"
 archives:
   - replacements:
       darwin: Darwin
@@ -21,6 +22,8 @@ archives:
       windows: Windows
       386: i386
       amd64: x86_64
+    format: binary
+    name_template: "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
 checksum:
   name_template: 'checksums.txt'
 snapshot:

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Bastian Doetsch
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,44 @@
+# mullvad-best-server
+![Build](https://github.com/bastiandoetsch/mullvad-best-server/actions/workflows/go.yml/badge.svg)
+
+Determines the mullvad.net server with the lowest latency. 
+
+## Installation
+
+Download binary from releases for your platform and unpack.
+
+## Usage
+### Default usage
+Execute `mullvad-best-server`. It outputs the code, e.g. `de05`. You can then connect to it with e.g. wireguard using the normal shell scripts.
+
+### Command line parameters
+
+```angular2html
+Usage of dist/mullvad-best-server_darwin_amd64/mullvad-best-server:
+-c string
+  Server country code, e.g. ch for Switzerland (default "ch")
+-o string
+  Output format. 'json' outputs server json
+-t string
+  Server type, e.g. wireguard (default "wireguard")
+```
+
+If you want the full server information, execute `mullvad-best-server -o json`. It returns the full json output  of the server information.
+The `-c` flag allows to give a country code. Else `ch` will be used.
+
+
+## Background
+The program uses `https://api.mullvad.net/www/relays/<SERVER_TYPE/` to get the current server list, pings the ones with the right country
+and outputs the server with the lowest ping.
+
+## Integration into a script
+I use it on my router like this (yes, I know I could have done the whole thing with jq and shell scripting, but wanted to use go for maintainability).
+```
+#!/bin/sh
+set -e
+LATEST_RELEASE=$(curl -sSL https://api.github.com/repos/bastiandoetsch/mullvad-best-server/releases/latest | jq -r '.assets[]| .browser_download_url' | grep Linux_arm64)
+curl -sSL $LATEST_RELEASE > /root/mullvad-best-server
+chmod +x /root/mullvad-best-server
+/usr/bin/wg-quick down $(wg show|grep interface | cut -d: -f2)  || echo "nothing to shut down"
+/usr/bin/wg-quick up "mullvad-$(/root/mullvad-best-server -c de)"
+```

main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"flag"
 	"fmt"
 	"github.com/go-ping/ping"
 	"github.com/rs/zerolog"
@@ -17,26 +18,36 @@ var pings = make(map[string]time.Duration)
 
 func main() {
 	zerolog.SetGlobalLevel(zerolog.InfoLevel)
-	servers := getServers()
-	bestIndex := selectBestServerIndex(servers)
-	log.Debug().Interface("server", servers[bestIndex]).Msg("Best latency server found.")
-	hostname := strings.Split(servers[bestIndex].Hostname, "-")[0]
+	var outputFlag = flag.String("o", "", "Output format. 'json' outputs server json")
+	var countryFlag = flag.String("c", "ch", "Server country code, e.g. ch for Switzerland")
+	var typeFlag = flag.String("t", "wireguard", "Server type, e.g. wireguard")
+	flag.Parse()
+
+	servers := getServers(*typeFlag)
+	bestIndex := selectBestServerIndex(servers, *countryFlag)
+	best := servers[bestIndex]
+	log.Debug().Interface("server", best).Msg("Best latency server found.")
+	hostname := strings.TrimSuffix(best.Hostname, "-wireguard")
+	if *outputFlag != "json" {
 		fmt.Println(hostname)
+	} else {
+		serverJson, err := json.Marshal(best)
+		if err != nil {
+			log.Fatal().Err(err)
+		}
+		fmt.Println(string(serverJson))
+	}
 }
 
-func selectBestServerIndex(servers []server) int {
+func selectBestServerIndex(servers []server, country string) int {
 	best := servers[0].Hostname
-	bestIndex := 0
-	allowedCountries := map[string]string{}
-	allowedCountries["de"] = "1"
-	allowedCountries["ch"] = "1"
-	allowedCountries["at"] = "1"
+	bestIndex := -1
 	for i, server := range servers {
-		if server.Active && allowedCountries[server.CountryCode] != "" {
+		if server.Active && server.CountryCode == country {
 			duration, err := serverLatency(server)
 			if err == nil {
 				pings[server.Hostname] = duration
-				if best == "" || pings[best] > pings[server.Hostname] {
+				if bestIndex == -1 || pings[best] > pings[server.Hostname] {
 					best = server.Hostname
 					bestIndex = i
 				}
@@ -46,8 +57,8 @@ func selectBestServerIndex(servers []server) int {
 	return bestIndex
 }
 
-func getServers() []server {
-	resp, err := http.Get("https://api.mullvad.net/www/relays/wireguard/")
+func getServers(serverType string) []server {
+	resp, err := http.Get("https://api.mullvad.net/www/relays/" + serverType + "/")
 	if err != nil {
 		log.Fatal().Err(err)
 	}