Add logging across app and centralized error handling

cmd/cgnolink/main.go

@@ -6,6 +6,8 @@ import (
 )
 
 func main() {
+	cgnolink.ConfigureLogger()
+
 	conf := cgnolink.NewConfig()
 
 	pool := database.Pool(conf)

err/err.go

@@ -1,47 +0,0 @@
-package err
-
-import (
-	"github.com/labstack/echo/v4"
-	"net/http"
-)
-
-type NotFoundError struct {
-	Message string
-}
-
-func (err NotFoundError) Error() string {
-	return err.Message
-}
-
-type UnknownError struct {
-	Message string
-}
-
-func (err UnknownError) Error() string {
-	return err.Message
-}
-
-type AlreadyExistsError struct {
-	Message string
-}
-
-func (err AlreadyExistsError) Error() string {
-	return err.Message
-}
-
-func MapErrToHTTPErr(err interface{}) *echo.HTTPError {
-	switch v := err.(type) {
-	case NotFoundError:
-		return echo.NewHTTPError(http.StatusNotFound, v.Message)
-	case UnknownError:
-		if v.Message != "" {
-			return echo.NewHTTPError(http.StatusInternalServerError, v.Message)
-		} else {
-			return echo.NewHTTPError(http.StatusInternalServerError)
-		}
-	case AlreadyExistsError:
-		return echo.NewHTTPError(http.StatusBadRequest, v.Message)
-	default:
-		return nil
-	}
-}

errors/errors.go

@@ -0,0 +1,25 @@
+package errors
+
+type NotFoundError struct {
+	Message string
+}
+
+func (err NotFoundError) Error() string {
+	return err.Message
+}
+
+type UnknownError struct {
+	Err error
+}
+
+func (err UnknownError) Error() string {
+	return err.Err.Error()
+}
+
+type AlreadyExistsError struct {
+	Message string
+}
+
+func (err AlreadyExistsError) Error() string {
+	return err.Message
+}

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/knadh/koanf v0.15.0
 	github.com/labstack/echo/v4 v4.2.1
 	github.com/mitchellh/copystructure v1.1.1 // indirect
+	github.com/rs/zerolog v1.20.0
 	golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 // indirect
 	golang.org/x/text v0.3.5 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect

go.sum

@@ -237,6 +237,8 @@ github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFR
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/zerolog v1.13.0/go.mod h1:YbFCdg8HfsridGWAh22vktObvhZbQsZXe4/zB0OKkWU=
 github.com/rs/zerolog v1.15.0/go.mod h1:xYTKnLHcpfU2225ny5qZjxnj9NvkumZYjJHlAThCjNc=
+github.com/rs/zerolog v1.20.0 h1:38k9hgtUBdxFwE34yS8rTHmHBa4eN16E4DJlv177LNs=
+github.com/rs/zerolog v1.20.0/go.mod h1:IzD0RJ65iWH0w97OQQebJEvTZYvsCUm9WVLWBQrJRjo=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v2.1.0+incompatible/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/ryanuber/go-glob v1.0.0/go.mod h1:807d1WSdnB0XRJzKNil9Om6lcp/3a0v4qIHxIXzX/Yc=
@@ -363,6 +365,7 @@ golang.org/x/tools v0.0.0-20190425163242-31fd60d6bfdc/go.mod h1:RgjU9mgBXZiqYHBn
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
 golang.org/x/tools v0.0.0-20190823170909-c4a336ef6a2f/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20190828213141-aed303cbaa74/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/xerrors v0.0.0-20190410155217-1f06c39b4373/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

link/handlers.go

@@ -1,7 +1,6 @@
 package link
 
 import (
-	. "cgnolink/err"
 	"encoding/json"
 	"github.com/jackc/pgx/v4/pgxpool"
 	"github.com/labstack/echo/v4"
@@ -16,7 +15,7 @@ func redirectHandler(c echo.Context, pool *pgxpool.Pool) error {
 
 	link, err := serv.GetById(linkId)
 	if err != nil {
-		return MapErrToHTTPErr(err)
+		return err
 	}
 
 	return c.Redirect(http.StatusSeeOther, link.RedirectURL.String())
@@ -36,7 +35,7 @@ func creationHandler(c echo.Context, pool *pgxpool.Pool) error {
 	serv := PgService{rep: PgRepository{pool: pool}}
 
 	if err = serv.Create(entity); err != nil {
-		return MapErrToHTTPErr(err)
+		return err
 	}
 
 	return c.NoContent(http.StatusCreated)
@@ -49,7 +48,7 @@ func retrievalByIdHandler(c echo.Context, pool *pgxpool.Pool) error {
 
 	l, err := serv.GetById(linkId)
 	if err != nil {
-		return MapErrToHTTPErr(err)
+		return err
 	}
 
 	return c.JSON(http.StatusOK, MapEntityToModel(l))
@@ -80,7 +79,7 @@ func allRetrievalHandler(c echo.Context, pool *pgxpool.Pool) error {
 
 	links, err := serv.GetAll(limit, offset)
 	if err != nil {
-		return MapErrToHTTPErr(err)
+		return err
 	}
 
 	models := make([]ResourceModel, len(links))
@@ -97,7 +96,7 @@ func removalHandler(c echo.Context, pool *pgxpool.Pool) error {
 	serv := PgService{rep: PgRepository{pool: pool}}
 
 	if err := serv.DeleteById(linkId); err != nil {
-		return MapErrToHTTPErr(err)
+		return err
 	}
 
 	return c.NoContent(http.StatusNoContent)

link/service.go

@@ -1,7 +1,7 @@
 package link
 
 import (
-	. "cgnolink/err"
+	apperrors "cgnolink/errors"
 )
 
 type Service interface {
@@ -18,15 +18,15 @@ type PgService struct {
 func (s *PgService) Create(link *Link) error {
 	existingLink, err := s.rep.FindById(link.Id)
 	if err != nil {
-		return UnknownError{}
+		return apperrors.UnknownError{Err: err}
 	}
 
 	if existingLink != nil {
-		return AlreadyExistsError{Message: "Link with given ID already exists."}
+		return apperrors.AlreadyExistsError{Message: "Link with given ID already exists."}
 	}
 
 	if err = s.rep.Save(link); err != nil {
-		return UnknownError{}
+		return apperrors.UnknownError{Err: err}
 	}
 
 	return nil
@@ -35,11 +35,11 @@ func (s *PgService) Create(link *Link) error {
 func (s *PgService) GetById(id string) (*Link, error) {
 	link, err := s.rep.FindById(id)
 	if err != nil {
-		return nil, UnknownError{}
+		return nil, apperrors.UnknownError{Err: err}
 	}
 
 	if link == nil {
-		return nil, NotFoundError{Message: "Link with given ID was not found."}
+		return nil, apperrors.NotFoundError{Message: "Link with given ID was not found."}
 	}
 
 	return link, nil
@@ -48,7 +48,7 @@ func (s *PgService) GetById(id string) (*Link, error) {
 func (s *PgService) GetAll(limit int, offset int) (Links, error) {
 	links, err := s.rep.FindAll(limit, offset)
 	if err != nil {
-		return nil, UnknownError{}
+		return nil, apperrors.UnknownError{Err: err}
 	}
 
 	return links, nil
@@ -56,7 +56,7 @@ func (s *PgService) GetAll(limit int, offset int) (Links, error) {
 
 func (s *PgService) DeleteById(id string) error {
 	if err := s.rep.DeleteById(id); err != nil {
-		return UnknownError{}
+		return apperrors.UnknownError{Err: err}
 	}
 
 	return nil

logger.go

@@ -0,0 +1,13 @@
+package cgnolink
+
+import (
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"os"
+	"time"
+)
+
+func ConfigureLogger() {
+	zerolog.TimeFieldFormat = time.RFC3339Nano
+	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr})
+}

middleware/logger.go

@@ -0,0 +1,34 @@
+package middleware
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/rs/zerolog/log"
+	"time"
+)
+
+func Logger() echo.MiddlewareFunc {
+	return func(next echo.HandlerFunc) echo.HandlerFunc {
+		return func(c echo.Context) (err error) {
+			req := c.Request()
+			res := c.Response()
+			start := time.Now()
+			if err = next(c); err != nil {
+				c.Error(err)
+			}
+			stop := time.Now()
+
+			log.Info().
+				Str("remote_ip", c.RealIP()).
+				Str("host", req.Host).
+				Str("uri", req.RequestURI).
+				Str("method", req.Method).
+				Str("path", req.URL.Path).
+				Str("user_agent", req.UserAgent()).
+				Int("status", res.Status).
+				Str("latency", stop.Sub(start).String()).
+				Send()
+
+			return
+		}
+	}
+}

server.go

@@ -1,17 +1,22 @@
 package cgnolink
 
 import (
+	apperrors "cgnolink/errors"
 	"cgnolink/link"
+	appmiddleware "cgnolink/middleware"
 	"github.com/jackc/pgx/v4/pgxpool"
 	"github.com/knadh/koanf"
 	"github.com/labstack/echo/v4"
 	"github.com/labstack/echo/v4/middleware"
+	"github.com/rs/zerolog/log"
 	"net/http"
 )
 
 func NewServer(conf *koanf.Koanf, pool *pgxpool.Pool) *echo.Echo {
 	server := echo.New()
 
+	server.HTTPErrorHandler = errorHandler(server)
+
 	addMiddleware(server, conf)
 	addHandlers(server, pool)
 
@@ -21,7 +26,7 @@ func NewServer(conf *koanf.Koanf, pool *pgxpool.Pool) *echo.Echo {
 func addMiddleware(s *echo.Echo, conf *koanf.Koanf) {
 	s.Use(middleware.CORS())
 
-	s.Use(middleware.Logger())
+	s.Use(appmiddleware.Logger())
 
 	s.Use(middleware.JWTWithConfig(middleware.JWTConfig{
 		Skipper: func(ctx echo.Context) bool {
@@ -43,3 +48,21 @@ func addHandlers(s *echo.Echo, pool *pgxpool.Pool) {
 
 	link.AddHandlers(s, pool)
 }
+
+func errorHandler(s *echo.Echo) echo.HTTPErrorHandler {
+	return func(err error, c echo.Context) {
+		mappedErr := err
+
+		switch v := err.(type) {
+		case apperrors.NotFoundError:
+			mappedErr = echo.NewHTTPError(http.StatusNotFound, v.Error())
+		case apperrors.UnknownError:
+			log.Err(v.Err).Send()
+			mappedErr = echo.NewHTTPError(http.StatusInternalServerError)
+		case apperrors.AlreadyExistsError:
+			mappedErr = echo.NewHTTPError(http.StatusBadRequest, v.Error())
+		}
+
+		s.DefaultHTTPErrorHandler(mappedErr, c)
+	}
+}