remove build folder after linting to enable clean state repo for goreleaser

.github/workflows/go.yml

@@ -19,7 +19,13 @@ 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

@@ -1,13 +1,12 @@
 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:
+  - flags:
+    - -trimpath
   - env:
       - CGO_ENABLED=0
     goos:
@@ -15,6 +14,7 @@ builds:
       - windows
       - darwin
     mod_timestamp: "{{ .CommitTimestamp }}"
+
 archives:
   - replacements:
       darwin: Darwin
@@ -24,10 +24,13 @@ archives:
       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:

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

@@ -30,3 +30,15 @@ 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

@@ -4,17 +4,16 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"github.com/go-ping/ping"
-	"github.com/rs/zerolog"
-	"github.com/rs/zerolog/log"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"strings"
 	"time"
-)
 
-var pings = make(map[string]time.Duration)
+	"github.com/go-ping/ping"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+)
 
 func main() {
 	zerolog.SetGlobalLevel(zerolog.InfoLevel)
@@ -40,16 +39,15 @@ func main() {
 }
 
 func selectBestServerIndex(servers []server, country string) int {
-	best := servers[0].Hostname
 	bestIndex := -1
+	var bestPing time.Duration
 	for i, server := range servers {
 		if server.Active && server.CountryCode == country {
 			duration, err := serverLatency(server)
 			if err == nil {
-				pings[server.Hostname] = duration
-				if bestIndex == -1 || pings[best] > pings[server.Hostname] {
-					best = server.Hostname
+				if bestIndex == -1 || bestPing > duration {
 					bestIndex = i
+					bestPing = duration
 				}
 			}
 		}
@@ -69,6 +67,9 @@ func getServers(serverType string) []server {
 			log.Err(err)
 		}
 	}(resp.Body)
+	if err != nil {
+		log.Fatal().Err(err)
+	}
 	var servers []server
 	err = json.Unmarshal(responseBody, &servers)
 	if err != nil {