Fix linter checks

internal/config/config.go

@@ -21,7 +21,6 @@ type Config struct {
 
 // Logging configuration.
 type Logging struct {
-
 	// AccessLog path.
 	AccessLog string `yaml:"accessLog,omitempty"`
 
@@ -34,14 +33,13 @@ type Logging struct {
 
 // Server configuration.
 type Server struct {
-
 	// PortHTTP is port where HTTP server must listen.
 	// If 0, HTTP is disabled.
-	PortHTTP int `yaml:"portHTTP,omitempty"`
+	PortHTTP int `yaml:"portHttp,omitempty"`
 
 	// PortHTTP is port where the HTTPS server must listen.
 	// If 0, HTTPS is disabled.
-	PortHTTPS int `yaml:"portHTTPS,omitempty"`
+	PortHTTPS int `yaml:"portHttps,omitempty"`
 
 	// TLSCertFile contains path to cert file for TLS Server.
 	TLSCertFile string `yaml:"tlsCertFile,omitempty"`
@@ -75,7 +73,7 @@ type Geo struct {
 	IPCache string `yaml:"ipCache,omitempty"`
 
 	// IPCacheDB contains the path to the SQLite DB with the IP Geodata cache.
-	IPCacheDB string `yaml:"ipCacheDB,omitempty"`
+	IPCacheDB string `yaml:"ipCacheDb,omitempty"`
 
 	IPCacheType types.CacheType `yaml:"cacheType,omitempty"`
 
@@ -83,7 +81,7 @@ type Geo struct {
 	LocationCache string `yaml:"locationCache,omitempty"`
 
 	// LocationCacheDB contains the path to the SQLite DB with the Location Geodata cache.
-	LocationCacheDB string `yaml:"locationCacheDB,omitempty"`
+	LocationCacheDB string `yaml:"locationCacheDb,omitempty"`
 
 	LocationCacheType types.CacheType `yaml:"locationCacheType,omitempty"`
 
@@ -165,5 +163,6 @@ func (c *Config) Dump() []byte {
 		// should never happen.
 		log.Fatalln("config.Dump():", err)
 	}
+
 	return data
 }

internal/geo/ip/convert.go

@@ -11,6 +11,7 @@ import (
 	"github.com/chubin/wttr.in/internal/util"
 )
 
+//nolint:cyclop
 func (c *Cache) ConvertCache() error {
 	dbfile := c.config.Geo.IPCacheDB
 
@@ -43,10 +44,12 @@ func (c *Cache) ConvertCache() error {
 		loc, err := c.Read(ip)
 		if err != nil {
 			log.Println("invalid entry for", ip)
+
 			continue
 		}
 
 		block = append(block, *loc)
+
 		if i%1000 != 0 || i == 0 {
 			continue
 		}
@@ -80,5 +83,6 @@ func createTable(db *godb.DB, tableName string) error {
 	`, tableName)
 
 	_, err := db.CurrentDB().Exec(createTable)
+
 	return err
 }

internal/geo/ip/ip.go

@@ -35,6 +35,7 @@ func (l *Location) String() string {
 			"%s;%s;%s;%s",
 			l.CountryCode, l.CountryCode, l.Region, l.City)
 	}
+
 	return fmt.Sprintf(
 		"%s;%s;%s;%s;%v;%v",
 		l.CountryCode, l.CountryCode, l.Region, l.City, l.Latitude, l.Longitude)
@@ -68,16 +69,18 @@ func NewCache(config *config.Config) (*Cache, error) {
 //
 // Format:
 //
-//     [CountryCode];Country;Region;City;[Latitude];[Longitude]
+//  [CountryCode];Country;Region;City;[Latitude];[Longitude]
 //
 // Example:
 //
-//     DE;Germany;Free and Hanseatic City of Hamburg;Hamburg;53.5736;9.9782
+//  DE;Germany;Free and Hanseatic City of Hamburg;Hamburg;53.5736;9.9782
 //
+
 func (c *Cache) Read(addr string) (*Location, error) {
 	if c.config.Geo.IPCacheType == types.CacheTypeDB {
 		return c.readFromCacheDB(addr)
 	}
+
 	return c.readFromCacheFile(addr)
 }
 
@@ -86,6 +89,7 @@ func (c *Cache) readFromCacheFile(addr string) (*Location, error) {
 	if err != nil {
 		return nil, types.ErrNotFound
 	}
+
 	return NewLocationFromString(addr, string(bytes))
 }
 
@@ -97,17 +101,19 @@ func (c *Cache) readFromCacheDB(addr string) (*Location, error) {
 	if err != nil {
 		return nil, err
 	}
+
 	return &result, nil
 }
 
 func (c *Cache) Put(addr string, loc *Location) error {
 	if c.config.Geo.IPCacheType == types.CacheTypeDB {
-		return c.putToCacheDB(addr, loc)
+		return c.putToCacheDB(loc)
 	}
+
 	return c.putToCacheFile(addr, loc)
 }
 
-func (c *Cache) putToCacheDB(addr string, loc *Location) error {
+func (c *Cache) putToCacheDB(loc *Location) error {
 	err := c.db.Insert(loc).Do()
 	// it should work like this:
 	//
@@ -121,14 +127,15 @@ func (c *Cache) putToCacheDB(addr string, loc *Location) error {
 	if strings.Contains(fmt.Sprint(err), "UNIQUE constraint failed") {
 		return c.db.Update(loc).Do()
 	}
+
 	return err
 }
 
-func (c *Cache) putToCacheFile(addr string, loc *Location) error {
-	return os.WriteFile(c.cacheFile(addr), []byte(loc.String()), 0644)
+func (c *Cache) putToCacheFile(addr string, loc fmt.Stringer) error {
+	return os.WriteFile(c.cacheFile(addr), []byte(loc.String()), 0o600)
 }
 
-// cacheFile retuns path to the cache entry for addr.
+// cacheFile returns path to the cache entry for addr.
 func (c *Cache) cacheFile(addr string) string {
 	return path.Join(c.config.Geo.IPCache, addr)
 }
@@ -170,14 +177,15 @@ func NewLocationFromString(addr, s string) (*Location, error) {
 	}, nil
 }
 
-// Reponse provides routing interface to the geo cache.
+// Response provides routing interface to the geo cache.
 //
 // Temporary workaround to switch IP addresses handling to the Go server.
 // Handles two queries:
 //
-//		/:geo-ip-put?ip=IP&value=VALUE
-//      /:geo-ip-get?ip=IP
+// - /:geo-ip-put?ip=IP&value=VALUE
+// - /:geo-ip-get?ip=IP
 //
+//nolint:cyclop
 func (c *Cache) Response(r *http.Request) *routing.Cadre {
 	var (
 		respERR = &routing.Cadre{Body: []byte("ERR")}
@@ -186,6 +194,7 @@ func (c *Cache) Response(r *http.Request) *routing.Cadre {
 
 	if ip := util.ReadUserIP(r); ip != "127.0.0.1" {
 		log.Printf("geoIP access from %s rejected\n", ip)
+
 		return nil
 	}
 
@@ -194,6 +203,7 @@ func (c *Cache) Response(r *http.Request) *routing.Cadre {
 		value := r.URL.Query().Get("value")
 		if !validIP4(ip) || value == "" {
 			log.Printf("invalid geoIP put query: ip='%s' value='%s'\n", ip, value)
+
 			return respERR
 		}
 
@@ -206,6 +216,7 @@ func (c *Cache) Response(r *http.Request) *routing.Cadre {
 		if err != nil {
 			return respERR
 		}
+
 		return respOK
 	}
 	if r.URL.Path == "/:geo-ip-get" {
@@ -218,12 +229,16 @@ func (c *Cache) Response(r *http.Request) *routing.Cadre {
 		if result == nil || err != nil {
 			return respERR
 		}
+
 		return &routing.Cadre{Body: []byte(result.String())}
 	}
+
 	return nil
 }
 
 func validIP4(ipAddress string) bool {
-	re, _ := regexp.Compile(`^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$`)
+	re := regexp.MustCompile(
+		`^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$`)
+
 	return re.MatchString(strings.Trim(ipAddress, " "))
 }

internal/geo/ip/ip_test.go

@@ -1,14 +1,17 @@
-package ip
+package ip_test
 
 import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
 
+	. "github.com/chubin/wttr.in/internal/geo/ip"
 	"github.com/chubin/wttr.in/internal/types"
 )
 
+//nolint:funlen
 func TestParseCacheEntry(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		addr     string
 		input    string

internal/geo/location/location.go

@@ -9,13 +9,14 @@ import (
 
 type Location struct {
 	Name     string `db:"name,key"`
-	Fullname string `db:"displayName" json:"display_name"`
 	Lat      string `db:"lat"`
 	Lon      string `db:"lon"`
 	Timezone string `db:"timezone"`
+	//nolint:tagliatelle
+	Fullname string `db:"displayName" json:"display_name"`
 }
 
-// String returns string represenation of location
+// String returns string representation of location.
 func (l *Location) String() string {
 	bytes, err := json.Marshal(l)
 	if err != nil {

internal/geo/location/nominatim.go

@@ -7,6 +7,8 @@ import (
 	"log"
 	"net/http"
 	"net/url"
+
+	"github.com/chubin/wttr.in/internal/types"
 )
 
 type Nominatim struct {
@@ -41,6 +43,7 @@ func (n *Nominatim) Query(location string) (*Location, error) {
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", n.name, err)
 	}
+	defer resp.Body.Close()
 
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
@@ -49,7 +52,7 @@ func (n *Nominatim) Query(location string) (*Location, error) {
 
 	err = json.Unmarshal(body, &errResponse)
 	if err == nil && errResponse.Error != "" {
-		return nil, fmt.Errorf("%s: %s", n.name, errResponse.Error)
+		return nil, fmt.Errorf("%w: %s: %s", types.ErrUpstream, n.name, errResponse.Error)
 	}
 
 	err = json.Unmarshal(body, &result)
@@ -58,9 +61,8 @@ func (n *Nominatim) Query(location string) (*Location, error) {
 	}
 
 	if len(result) != 1 {
-		return nil, fmt.Errorf("%s: invalid response", n.name)
+		return nil, fmt.Errorf("%w: %s: invalid response", types.ErrUpstream, n.name)
 	}
 
 	return &result[0], nil
-
 }

internal/logging/logging.go

@@ -63,6 +63,7 @@ func (rl *RequestLogger) Log(r *http.Request) error {
 	if time.Since(rl.lastFlush) > rl.period {
 		return rl.flush()
 	}
+
 	return nil
 }
 
@@ -85,7 +86,8 @@ func (rl *RequestLogger) flush() error {
 		}
 
 		// Open log file.
-		f, err := os.OpenFile(rl.filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+		//nolint:nosnakecase
+		f, err := os.OpenFile(rl.filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0o600)
 		if err != nil {
 			return err
 		}

internal/logging/suppress.go

@@ -31,11 +31,15 @@ func NewLogSuppressor(filename string, suppress []string, linePrefix string) *Lo
 
 // Open opens log file.
 func (ls *LogSuppressor) Open() error {
+	var err error
+
 	if ls.filename == "" {
 		return nil
 	}
-	var err error
-	ls.logFile, err = os.OpenFile(ls.filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
+
+	//nolint:nosnakecase
+	ls.logFile, err = os.OpenFile(ls.filename, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0o600)
+
 	return err
 }
 
@@ -44,15 +48,14 @@ func (ls *LogSuppressor) Close() error {
 	if ls.filename == "" {
 		return nil
 	}
+
 	return ls.logFile.Close()
 }
 
 // Write writes p to log, and returns number f bytes written.
 // Implements io.Writer interface.
-func (ls *LogSuppressor) Write(p []byte) (n int, err error) {
-	var (
-		output string
-	)
+func (ls *LogSuppressor) Write(p []byte) (int, error) {
+	var output string
 
 	if ls.filename == "" {
 		return os.Stdin.Write(p)
@@ -63,19 +66,19 @@ func (ls *LogSuppressor) Write(p []byte) (n int, err error) {
 
 	lines := strings.Split(string(p), ls.linePrefix)
 	for _, line := range lines {
-		if (func() bool {
+		if (func(line string) bool {
 			for _, suppress := range ls.suppress {
 				if strings.Contains(line, suppress) {
 					return true
 				}
 			}
+
 			return false
-		})() {
+		})(line) {
 			continue
 		}
 		output += line
 	}
 
-	n, err = ls.logFile.Write([]byte(output))
-	return n, err
+	return ls.logFile.Write([]byte(output))
 }

internal/processor/peak.go

@@ -9,38 +9,49 @@ import (
 	"github.com/robfig/cron"
 )
 
-func (rp *RequestProcessor) startPeakHandling() {
+func (rp *RequestProcessor) startPeakHandling() error {
+	var err error
+
 	c := cron.New()
 	// cronTime := fmt.Sprintf("%d,%d * * * *", 30-prefetchInterval/60, 60-prefetchInterval/60)
-	c.AddFunc(
+	err = c.AddFunc(
 		"24 * * * *",
 		func() { rp.prefetchPeakRequests(&rp.peakRequest30) },
 	)
-	c.AddFunc(
+	if err != nil {
+		return err
+	}
+
+	err = c.AddFunc(
 		"54 * * * *",
 		func() { rp.prefetchPeakRequests(&rp.peakRequest60) },
 	)
+	if err != nil {
+		return err
+	}
+
 	c.Start()
+
+	return nil
 }
 
 func (rp *RequestProcessor) savePeakRequest(cacheDigest string, r *http.Request) {
-	_, min, _ := time.Now().Clock()
-	if min == 30 {
+	if _, min, _ := time.Now().Clock(); min == 30 {
 		rp.peakRequest30.Store(cacheDigest, *r)
 	} else if min == 0 {
 		rp.peakRequest60.Store(cacheDigest, *r)
 	}
 }
 
-func (rp *RequestProcessor) prefetchRequest(r *http.Request) {
-	rp.ProcessRequest(r)
+func (rp *RequestProcessor) prefetchRequest(r *http.Request) error {
+	_, err := rp.ProcessRequest(r)
+
+	return err
 }
 
 func syncMapLen(sm *sync.Map) int {
 	count := 0
-
 	f := func(key, value interface{}) bool {
-
 		// Not really certain about this part, don't know for sure
 		// if this is a good check for an entry's existence
 		if key == "" {
@@ -65,10 +76,14 @@ func (rp *RequestProcessor) prefetchPeakRequests(peakRequestMap *sync.Map) {
 	sleepBetweenRequests := time.Duration(rp.config.Uplink.PrefetchInterval*1000/peakRequestLen) * time.Millisecond
 	peakRequestMap.Range(func(key interface{}, value interface{}) bool {
 		go func(r http.Request) {
-			rp.prefetchRequest(&r)
+			err := rp.prefetchRequest(&r)
+			if err != nil {
+				log.Println("prefetch request:", err)
+			}
 		}(value.(http.Request))
 		peakRequestMap.Delete(key)
 		time.Sleep(sleepBetweenRequests)
+
 		return true
 	})
 }

internal/processor/processor.go

@@ -22,19 +22,21 @@ import (
 )
 
 // plainTextAgents contains signatures of the plain-text agents.
-var plainTextAgents = []string{
-	"curl",
-	"httpie",
-	"lwp-request",
-	"wget",
-	"python-httpx",
-	"python-requests",
-	"openbsd ftp",
-	"powershell",
-	"fetch",
-	"aiohttp",
-	"http_get",
-	"xh",
+func plainTextAgents() []string {
+	return []string{
+		"curl",
+		"httpie",
+		"lwp-request",
+		"wget",
+		"python-httpx",
+		"python-requests",
+		"openbsd ftp",
+		"powershell",
+		"fetch",
+		"aiohttp",
+		"http_get",
+		"xh",
+	}
 }
 
 type responseWithHeader struct {
@@ -99,8 +101,8 @@ func NewRequestProcessor(config *config.Config) (*RequestProcessor, error) {
 }
 
 // Start starts async request processor jobs, such as peak handling.
-func (rp *RequestProcessor) Start() {
-	rp.startPeakHandling()
+func (rp *RequestProcessor) Start() error {
+	return rp.startPeakHandling()
 }
 
 func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader, error) {
@@ -124,11 +126,13 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader
 
 	if resp, ok := redirectInsecure(r); ok {
 		rp.stats.Inc("redirects")
+
 		return resp, nil
 	}
 
 	if dontCache(r) {
 		rp.stats.Inc("uncached")
+
 		return get(r, rp.upstreamTransport)
 	}
 
@@ -193,11 +197,11 @@ func (rp *RequestProcessor) ProcessRequest(r *http.Request) (*responseWithHeader
 			rp.lruCache.Remove(cacheDigest)
 		}
 	}
+
 	return response, nil
 }
 
 func get(req *http.Request, transport *http.Transport) (*responseWithHeader, error) {
-
 	client := &http.Client{
 		Transport: transport,
 	}
@@ -226,6 +230,7 @@ func get(req *http.Request, transport *http.Transport) (*responseWithHeader, err
 	if err != nil {
 		return nil, err
 	}
+	defer res.Body.Close()
 
 	body, err := ioutil.ReadAll(res.Body)
 	if err != nil {
@@ -241,9 +246,8 @@ func get(req *http.Request, transport *http.Transport) (*responseWithHeader, err
 	}, nil
 }
 
-// implementation of the cache.get_signature of original wttr.in
+// getCacheDigest is an implementation of the cache.get_signature of original wttr.in.
 func getCacheDigest(req *http.Request) string {
-
 	userAgent := req.Header.Get("User-Agent")
 
 	queryHost := req.Host
@@ -256,11 +260,11 @@ func getCacheDigest(req *http.Request) string {
 	return fmt.Sprintf("%s:%s%s:%s:%s", userAgent, queryHost, queryString, clientIPAddress, lang)
 }
 
-// return true if request should not be cached
+// dontCache returns true if req should not be cached.
 func dontCache(req *http.Request) bool {
-
 	// dont cache cyclic requests
 	loc := strings.Split(req.RequestURI, "?")[0]
+
 	return strings.Contains(loc, ":")
 }
 
@@ -269,10 +273,7 @@ func dontCache(req *http.Request) bool {
 //
 // Insecure queries are marked by the frontend web server
 // with X-Forwarded-Proto header:
-//
-//    proxy_set_header   X-Forwarded-Proto $scheme;
-//
-//
+// `proxy_set_header   X-Forwarded-Proto $scheme;`.
 func redirectInsecure(req *http.Request) (*responseWithHeader, bool) {
 	if isPlainTextAgent(req.Header.Get("User-Agent")) {
 		return nil, false
@@ -304,14 +305,15 @@ The document has moved
 	}, true
 }
 
-// isPlainTextAgent returns true if userAgent is a plain-text agent
+// isPlainTextAgent returns true if userAgent is a plain-text agent.
 func isPlainTextAgent(userAgent string) bool {
 	userAgentLower := strings.ToLower(userAgent)
-	for _, signature := range plainTextAgents {
+	for _, signature := range plainTextAgents() {
 		if strings.Contains(userAgentLower, signature) {
 			return true
 		}
 	}
+
 	return false
 }
 
@@ -325,6 +327,7 @@ func ipFromAddr(s string) string {
 	if pos == -1 {
 		return s
 	}
+
 	return s[:pos]
 }
 
@@ -336,5 +339,4 @@ func fromCadre(cadre *routing.Cadre) *responseWithHeader {
 		StatusCode: 200,
 		InProgress: false,
 	}
-
 }

internal/routing/routing.go

@@ -56,6 +56,7 @@ func (r *Router) Route(req *http.Request) Handler {
 			return re.Handler
 		}
 	}
+
 	return nil
 }
 

internal/stats/stats.go

@@ -36,6 +36,7 @@ func (c *Stats) Inc(key string) {
 func (c *Stats) Get(key string) int {
 	c.m.Lock()
 	defer c.m.Unlock()
+
 	return c.v[key]
 }
 
@@ -45,14 +46,13 @@ func (c *Stats) Reset(key string) int {
 	defer c.m.Unlock()
 	result := c.v[key]
 	c.v[key] = 0
+
 	return result
 }
 
 // Show returns current statistics formatted as []byte.
 func (c *Stats) Show() []byte {
-	var (
-		b bytes.Buffer
-	)
+	var b bytes.Buffer
 
 	c.m.Lock()
 	defer c.m.Unlock()
@@ -63,11 +63,13 @@ func (c *Stats) Show() []byte {
 	fmt.Fprintf(&b, "%-20s: %d\n", "Uptime (min)", uptime/60)
 
 	fmt.Fprintf(&b, "%-20s: %d\n", "Total queries", c.v["total"])
+
 	if uptime != 0 {
 		fmt.Fprintf(&b, "%-20s: %d\n", "Throughput (QpM)", c.v["total"]*60/int(uptime))
 	}
 
 	fmt.Fprintf(&b, "%-20s: %d\n", "Cache L1 queries", c.v["cache1"])
+
 	if c.v["total"] != 0 {
 		fmt.Fprintf(&b, "%-20s: %d\n", "Cache L1 queries (%)", (100*c.v["cache1"])/c.v["total"])
 	}

internal/types/errors.go

@@ -0,0 +1,9 @@
+package types
+
+import "errors"
+
+var (
+	ErrNotFound          = errors.New("cache entry not found")
+	ErrInvalidCacheEntry = errors.New("invalid cache entry format")
+	ErrUpstream          = errors.New("upstream error")
+)

internal/types/types.go

@@ -1,15 +1,8 @@
 package types
 
-import "errors"
-
 type CacheType string
 
 const (
 	CacheTypeDB    = "db"
 	CacheTypeFiles = "files"
 )
-
-var (
-	ErrNotFound          = errors.New("cache entry not found")
-	ErrInvalidCacheEntry = errors.New("invalid cache entry format")
-)

internal/util/http.go

@@ -21,5 +21,6 @@ func ReadUserIP(r *http.Request) string {
 			log.Printf("ERROR: userip: %q is not IP:port\n", IPAddress)
 		}
 	}
+
 	return IPAddress
 }

internal/util/yaml.go

@@ -10,5 +10,6 @@ import (
 func YamlUnmarshalStrict(in []byte, out interface{}) error {
 	dec := yaml.NewDecoder(bytes.NewReader(in))
 	dec.KnownFields(true)
+
 	return dec.Decode(out)
 }

srv.go

@@ -18,15 +18,15 @@ import (
 	"github.com/chubin/wttr.in/internal/processor"
 )
 
+//nolint:gochecknoglobals
 var cli struct {
-	ConfigCheck bool   `name:"config-check" help:"Check configuration"`
-	ConfigDump  bool   `name:"config-dump" help:"Dump configuration"`
-	GeoResolve  string `name:"geo-resolve" help:"Resolve location"`
-
 	ConfigFile string `name:"config-file" arg:"" optional:"" help:"Name of configuration file"`
 
-	ConvertGeoIPCache       bool `name:"convert-geo-ip-cache" help:"Convert Geo IP data cache to SQlite"`
-	ConvertGeoLocationCache bool `name:"convert-geo-location-cache" help:"Convert Geo Location data cache to SQlite"`
+	ConfigCheck             bool   `name:"config-check" help:"Check configuration"`
+	ConfigDump              bool   `name:"config-dump" help:"Dump configuration"`
+	ConvertGeoIPCache       bool   `name:"convert-geo-ip-cache" help:"Convert Geo IP data cache to SQlite"`
+	ConvertGeoLocationCache bool   `name:"convert-geo-location-cache" help:"Convert Geo Location data cache to SQlite"`
+	GeoResolve              string `name:"geo-resolve" help:"Resolve location"`
 }
 
 const logLineStart = "LOG_LINE_START "
@@ -84,7 +84,7 @@ func serve(conf *config.Config) error {
 		rp *processor.RequestProcessor
 
 		// errs is the servers errors channel.
-		errs chan error = make(chan error, 1)
+		errs = make(chan error, 1)
 
 		// numberOfServers started. If 0, exit.
 		numberOfServers int
@@ -110,15 +110,18 @@ func serve(conf *config.Config) error {
 
 	rp, err = processor.NewRequestProcessor(conf)
 	if err != nil {
-		log.Fatalln("log processor initialization:", err)
+		return fmt.Errorf("log processor initialization: %w", err)
 	}
 
 	err = errorsLog.Open()
 	if err != nil {
-		log.Fatalln("errors log:", err)
+		return err
 	}
 
-	rp.Start()
+	err = rp.Start()
+	if err != nil {
+		return err
+	}
 
 	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		if err := logger.Log(r); err != nil {
@@ -128,17 +131,22 @@ func serve(conf *config.Config) error {
 		response, err := rp.ProcessRequest(r)
 		if err != nil {
 			log.Println(err)
+
 			return
 		}
 		if response.StatusCode == 0 {
 			log.Println("status code 0", response)
+
 			return
 		}
 
 		copyHeader(w.Header(), response.Header)
 		w.Header().Set("Access-Control-Allow-Origin", "*")
 		w.WriteHeader(response.StatusCode)
-		w.Write(response.Body)
+		_, err = w.Write(response.Body)
+		if err != nil {
+			log.Println(err)
+		}
 	})
 
 	if conf.Server.PortHTTP != 0 {
@@ -152,6 +160,7 @@ func serve(conf *config.Config) error {
 	if numberOfServers == 0 {
 		return errors.New("no servers configured")
 	}
+
 	return <-errs // block until one of the servers writes an error
 }
 
@@ -185,7 +194,9 @@ func main() {
 		if err != nil {
 			ctx.FatalIfErrorf(err)
 		}
+
 		ctx.FatalIfErrorf(geoIPCache.ConvertCache())
+
 		return
 	}
 
@@ -194,7 +205,9 @@ func main() {
 		if err != nil {
 			ctx.FatalIfErrorf(err)
 		}
+
 		ctx.FatalIfErrorf(geoLocCache.ConvertCache())
+
 		return
 	}
 
@@ -204,7 +217,6 @@ func main() {
 		ctx.FatalIfErrorf(err)
 		if loc != nil {
 			fmt.Println(*loc)
-
 		}
 	}