recover gracefully if no server found

.github/workflows/go.yml

@@ -20,6 +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

@@ -5,15 +5,15 @@ before:
     - go mod tidy
 
 builds:
-  - env:
+  - flags:
+    - -trimpath
+    env:
       - CGO_ENABLED=0
     goos:
       - linux
       - windows
       - darwin
     mod_timestamp: "{{ .CommitTimestamp }}"
-    ldflags:
-      - -s -w
 
 archives:
   - replacements:

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

@@ -17,6 +17,8 @@ Execute `mullvad-best-server`. It outputs the code, e.g. `de05`. You can then co
 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

main.go

@@ -4,25 +4,34 @@ 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"
+
+	"github.com/go-ping/ping"
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
 )
 
 func main() {
-	zerolog.SetGlobalLevel(zerolog.InfoLevel)
 	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()
 
+	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")
@@ -66,6 +75,9 @@ 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 {