Fix some error logging - Msg() needs to be called for exiting with exit 1

.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
@@ -18,6 +20,12 @@ jobs:
     - name: Test
       run: go test -v ./...
 
+    - name: Lint source code
+      run: |
+        make tools lint
+        rm -rf .bin/
+        rm -rf dist/
+
     - name: Create release tag
       run: |
         git tag "v$(git show -s --format=%cd --date=format:%Y%m%d.%H%M%S)"

.golangci.yaml

@@ -0,0 +1,26 @@
+linters:
+  disable-all: true
+  enable:
+    - deadcode
+    - errcheck
+    - gofmt
+    - goimports
+    - gosimple
+    - ineffassign
+    - misspell
+    - staticcheck
+    - structcheck
+    - unconvert
+    - unused
+    - varcheck
+    - govet
+
+linters-settings:
+  goimports:
+    local-prefixes: github.com/bastiandoetsch/mullvad-best-server
+
+output:
+  format: tab
+
+run:
+  deadline: 10m

.goreleaser.yaml

@@ -1,19 +1,20 @@
 project_name: mullvad-best-server
-# This is an example .goreleaser.yml file with some sensible defaults.
-# Make sure to check the documentation at https://goreleaser.com
+
 before:
   hooks:
-    # You may remove this if you don't use go modules.
     - go mod tidy
-    # you may remove this if you don't need go generate
-    - go generate ./...
+
 builds:
-  - env:
+  - flags:
+    - -trimpath
+    env:
       - CGO_ENABLED=0
     goos:
       - linux
       - windows
       - darwin
+    mod_timestamp: "{{ .CommitTimestamp }}"
+
 archives:
   - replacements:
       darwin: Darwin
@@ -21,10 +22,15 @@ archives:
       windows: Windows
       386: i386
       amd64: x86_64
+    format: binary
+    name_template: "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}"
+
 checksum:
   name_template: 'checksums.txt'
+
 snapshot:
   name_template: "{{ incpatch .Version }}-next"
+
 changelog:
   sort: asc
   filters:

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.

Makefile

@@ -0,0 +1,60 @@
+# project variables
+PROJECT_NAME := mullvad-best-server
+
+# build variables
+.DEFAULT_GOAL = lint
+BUILD_DIR := dist
+DEV_GOARCH := $(shell go env GOARCH)
+DEV_GOOS := $(shell go env GOOS)
+
+
+## tools: Install required tooling.
+.PHONY: tools
+tools:
+ifeq (,$(wildcard ./.bin/golangci-lint*))
+	@curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b .bin/ v1.44.2
+else
+	@echo "==> Required tooling is already installed"
+endif
+
+## clean: Delete the build directory
+.PHONY: clean
+clean:
+	@echo "==> Removing '$(BUILD_DIR)' directory..."
+	@rm -rf $(BUILD_DIR)
+
+## lint: Lint code with golangci-lint.
+.PHONY: lint
+lint: tools
+	@echo "==> Linting code with 'golangci-lint'..."
+	@.bin/golangci-lint run ./...
+
+## test: Run all unit tests.
+.PHONY: test
+test:
+	@echo "==> Running unit tests..."
+	@mkdir -p $(BUILD_DIR)
+	@go test -count=1 -v -cover -coverprofile=$(BUILD_DIR)/coverage.out -parallel=4 ./...
+
+## build: Build binary for default local system's OS and architecture.
+.PHONY: build
+build:
+	@echo "==> Building binary..."
+	@echo "    running go build for GOOS=$(DEV_GOOS) GOARCH=$(DEV_GOARCH)"
+# workaround for missing .exe extension on Windows
+ifeq ($(OS),Windows_NT)
+	@go build -o $(BUILD_DIR)/$(PROJECT_NAME).$(DEV_GOOS).$(DEV_GOARCH).exe
+else
+	@go build -o $(BUILD_DIR)/$(PROJECT_NAME).$(DEV_GOOS).$(DEV_GOARCH)
+endif
+
+.PHONY: run
+run:
+	@echo "==> Running $(PROJECT_NAME)"
+	@go run main.go
+
+help: Makefile
+	@echo "Usage: make <command>"
+	@echo ""
+	@echo "Commands:"
+	@sed -n 's/^##//p' $< | column -t -s ':' | sed -e 's/^/ /'

README.md

@@ -0,0 +1,46 @@
+# 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")
+-l string
+  Log level. Allowed values: trace, debug, info, warn, error, fatal, panic (default "info")
+-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

@@ -2,38 +2,60 @@ package main
 
 import (
 	"encoding/json"
-	"github.com/go-ping/ping"
-	"github.com/rs/zerolog/log"
+	"flag"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
+	"strings"
 	"time"
+
+	"github.com/go-ping/ping"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
 )
 
-var pings = make(map[string]time.Duration)
-
 func main() {
+	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")
+	var logLevel = flag.String("l", "info", "Log level. Allowed values: trace, debug, info, warn, error, fatal, panic")
+	flag.Parse()
 
-	servers := getServers()
-	bestIndex := selectBestServerIndex(servers)
-	log.Info().Interface("best", servers[bestIndex]).Msg("Best Latency Server found.")
+	level, err := zerolog.ParseLevel(*logLevel)
+	if err != nil {
+		log.Fatal().Err(err).Msg("Unable to set log level")
+	}
+	zerolog.SetGlobalLevel(level)
+	servers := getServers(*typeFlag)
+	bestIndex := selectBestServerIndex(servers, *countryFlag)
+	if bestIndex == -1 {
+		log.Fatal().Str("country", *countryFlag).Msg("No servers for country found.")
+	}
+	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).Msg("Couldn't marshal server information to Json")
+		}
+		fmt.Println(string(serverJson))
+	}
 }
 
-func selectBestServerIndex(servers []server) int {
-	best := servers[0].Hostname
-	bestIndex := 0
-	allowedCountries := map[string]string{}
-	allowedCountries["de"] = "1"
-	allowedCountries["ch"] = "1"
-	allowedCountries["at"] = "1"
+func selectBestServerIndex(servers []server, country string) int {
+	bestIndex := -1
+	var bestPing time.Duration
 	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] {
-					best = server.Hostname
+				if bestIndex == -1 || bestPing > duration {
 					bestIndex = i
+					bestPing = duration
 				}
 			}
 		}
@@ -41,10 +63,10 @@ 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)
+		log.Fatal().Err(err).Msg("Couldn't retrieve servers")
 	}
 	responseBody, err := ioutil.ReadAll(resp.Body)
 	defer func(Body io.ReadCloser) {
@@ -53,10 +75,13 @@ func getServers() []server {
 			log.Err(err)
 		}
 	}(resp.Body)
+	if err != nil {
+		log.Fatal().Err(err)
+	}
 	var servers []server
 	err = json.Unmarshal(responseBody, &servers)
 	if err != nil {
-		log.Fatal().Err(err)
+		log.Fatal().Err(err).Msg("couldn't unmarshall server json")
 	}
 	return servers
 }
@@ -69,7 +94,7 @@ func serverLatency(s server) (time.Duration, error) {
 	}
 	var duration time.Duration
 	pinger.OnRecv = func(pkt *ping.Packet) {
-		log.Info().Str("Server", s.Hostname).IPAddr("IP", pkt.IPAddr.IP).Dur("RTT", pkt.Rtt).Msg("Added server latency.")
+		log.Debug().Str("Server", s.Hostname).IPAddr("IP", pkt.IPAddr.IP).Dur("RTT", pkt.Rtt).Msg("Added server latency.")
 		duration = pkt.Rtt
 	}
 	err = pinger.Run()