Add code checks, and resolve check errors

* gofmt
* errcheck: check if there is unchecked errors
  check if we correctly catch every errors
* gocyclo: check if cyclomatic complexity is over 15
  Help keeping functions simple
* gosimple: check if code can be simplified

Makefile

@@ -5,6 +5,8 @@ GIT_REPOSITORY		:= github.com/fydrah/loginapp
 GIT_COMMIT_ID		:= $(shell git log -n 1 --pretty=format:%h)
 GIT_TAG			:= $(shell git describe --tags)
 DOCKERFILES		:= dockerfiles
+CYCLO_MAX		:= 15
+SRC_FILES		:= $(shell find . -name "*.go" -not -path "./vendor*")
 
 LDFLAGS			= -w -s -X main.GitVersion=$(GIT_TAG) -X main.GitHash=$(GIT_COMMIT_ID)
 
@@ -23,3 +25,31 @@ build-static:
 .PHONY: docker-tmp
 docker-tmp:
 	docker build -t $(DOCKER_REPOSITORY):$(GIT_COMMIT_ID) .
+
+.PHONY: checks
+checks: errcheck gocyclo gosimple
+
+.PHONY: gofmt
+gofmt:
+	gofmt -w -s $(SRC_FILES)
+
+.PHONY: errcheck
+errcheck:
+	@echo
+	@echo "############ Run unchecked errors check"
+	which errcheck || go get github.com/kisielk/errcheck
+	errcheck $(GIT_REPOSITORY)
+
+.PHONY: gocyclo
+gocyclo:
+	@echo
+	@echo "############ Run cyclomatic complexity check"
+	which gocyclo || go get github.com/fzipp/gocyclo
+	gocyclo -over $(CYCLO_MAX) $(SRC_FILES)
+
+.PHONY: gosimple
+gosimple:
+	@echo
+	@echo "############ Run simplifying code check (codes reference at https://staticcheck.io/docs/gosimple)"
+	which gosimple || go get honnef.co/go/tools/cmd/gosimple
+	gosimple $(GIT_REPOSITORY)

config.go

@@ -17,10 +17,10 @@ package main
 
 import (
 	"fmt"
+	"github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
 	"io/ioutil"
 	"strings"
-	"github.com/sirupsen/logrus"
 )
 
 type AppConfig struct {
@@ -41,13 +41,13 @@ type AppConfig struct {
 		CrossClients   []string `yaml:"cross_clients"`
 	} `yaml:"oidc"`
 	Tls struct {
-		Enabled	bool	`yaml:"enabled"`
-		Cert	string	`yaml:"cert"`
-		Key	string	`yaml:"key"`
+		Enabled bool   `yaml:"enabled"`
+		Cert    string `yaml:"cert"`
+		Key     string `yaml:"key"`
 	} `yaml:"tls"`
 	Log struct {
-		Level	string	`yaml:"level"`
-		Format	string	`yaml:"format"`
+		Level  string `yaml:"level"`
+		Format string `yaml:"format"`
 	} `yaml:"log"`
 }
 
@@ -60,27 +60,27 @@ func (a *AppConfig) Init(config string) error {
 		return fmt.Errorf("error parse config file %s: %v", config, err)
 	}
 	switch f := strings.ToLower(a.Log.Format); f {
-		case "json":
-			logger.Formatter = &logrus.JSONFormatter{}
-		case "text":
-			logger.Formatter = &logrus.TextFormatter{}
-		default:
-			logger.Formatter = &logrus.JSONFormatter{}
-			logger.Warningf("Format %q not available, use json|text. Using json format", f)
+	case "json":
+		logger.Formatter = &logrus.JSONFormatter{}
+	case "text":
+		logger.Formatter = &logrus.TextFormatter{}
+	default:
+		logger.Formatter = &logrus.JSONFormatter{}
+		logger.Warningf("Format %q not available, use json|text. Using json format", f)
 	}
 	logger.Debugf("Using %s log format", a.Log.Format)
 	switch f := strings.ToLower(a.Log.Level); f {
-		case "debug":
-			logger.Level = logrus.DebugLevel
-		case "info":
-			logger.Level = logrus.InfoLevel
-		case "warning":
-			logger.Level = logrus.WarnLevel
-		case "error":
-			logger.Level = logrus.ErrorLevel
-		default:
-			logger.Level = logrus.InfoLevel
-			logger.Warningf("Log level %q not available, use debug|info|warning|error. Using Info log level", f)
+	case "debug":
+		logger.Level = logrus.DebugLevel
+	case "info":
+		logger.Level = logrus.InfoLevel
+	case "warning":
+		logger.Level = logrus.WarnLevel
+	case "error":
+		logger.Level = logrus.ErrorLevel
+	default:
+		logger.Level = logrus.InfoLevel
+		logger.Warningf("Log level %q not available, use debug|info|warning|error. Using Info log level", f)
 	}
 	logger.Debugf("Using %s log level", a.Log.Format)
 	logger.Debugf("Configuration loaded: %+v", a)

main.go

@@ -21,22 +21,22 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"github.com/cenkalti/backoff"
 	"github.com/coreos/go-oidc"
 	"github.com/julienschmidt/httprouter"
+	"github.com/sirupsen/logrus"
+	"github.com/urfave/cli"
 	"golang.org/x/oauth2"
 	"net/http"
 	"os"
-	"github.com/urfave/cli"
-	"github.com/sirupsen/logrus"
-	"time"
 	"strings"
-	"github.com/cenkalti/backoff"
+	"time"
 )
 
 var (
 	GitVersion = "X.X.X"
-	GitHash = "XXXXXXX"
-	logger = logrus.New()
+	GitHash    = "XXXXXXX"
+	logger     = logrus.New()
 )
 
 /**
@@ -79,9 +79,7 @@ func (s *Server) PrepareCallbackUrl(endpoint string) string {
 		authCodeURL string
 	)
 
-	for _, extra_scope := range s.config.OIDC.ExtraScopes {
-		scopes = append(scopes, extra_scope)
-	}
+	scopes = append(scopes, s.config.OIDC.ExtraScopes...)
 	// Prepare cross client auth
 	// see https://github.com/coreos/dex/blob/master/Documentation/custom-scopes-claims-clients.md
 	for _, cross_client := range s.config.OIDC.CrossClients {
@@ -190,7 +188,9 @@ func (s *Server) ProcessCallback(w http.ResponseWriter, r *http.Request, c strin
 		return KubeUserInfo{}, fmt.Errorf("Failed to unmarshal claims from idToken: %v", err)
 	}
 	buff := new(bytes.Buffer)
-	json.Indent(buff, []byte(claims), "", "  ")
+	if err := json.Indent(buff, []byte(claims), "", "  "); err != nil {
+		return KubeUserInfo{}, fmt.Errorf("Failed to format claims output: %v", err)
+	}
 	if err := json.Unmarshal(claims, &json_claims); err != nil {
 		panic(err)
 	}
@@ -213,13 +213,13 @@ func loggingHandler(next http.Handler) http.Handler {
 		t1 := time.Now()
 		next.ServeHTTP(w, r)
 		t2 := time.Now()
-	logger.WithFields(logrus.Fields{
-		"method": r.Method,
-		"path": r.URL.String(),
-		"request_duration": fmt.Sprintf("%s",t2.Sub(t1)),
-		"protocol": r.Proto,
-		"remote_address": r.RemoteAddr,
-	}).Info()
+		logger.WithFields(logrus.Fields{
+			"method":           r.Method,
+			"path":             r.URL.String(),
+			"request_duration": t2.Sub(t1).String(),
+			"protocol":         r.Proto,
+			"remote_address":   r.RemoteAddr,
+		}).Info()
 	}
 	return http.HandlerFunc(fn)
 }
@@ -229,8 +229,8 @@ func loggingHandler(next http.Handler) http.Handler {
  */
 func (s *Server) Run() error {
 	var (
-		provider	*oidc.Provider
-		backoffErr	error
+		provider   *oidc.Provider
+		backoffErr error
 	)
 	// router setup
 	s.router = httprouter.New()
@@ -323,23 +323,25 @@ GLOBAL OPTIONS:
 	app.UsageText = "Simple application for Kubernetes CLI configuration with OIDC"
 	app.Version = fmt.Sprintf("%v build %v", GitVersion, GitHash)
 	app.Authors = []cli.Author{
-		cli.Author{
+		{
 			Name:  "fydrah",
 			Email: "flav.hardy@gmail.com",
 		},
 	}
 	app.Commands = []cli.Command{
 		{
-			Name: "serve",
-			Usage: "Run loginapp application",
+			Name:            "serve",
+			Usage:           "Run loginapp application",
 			SkipFlagParsing: true,
-			ArgsUsage: "[configuration file]",
+			ArgsUsage:       "[configuration file]",
 			Before: func(c *cli.Context) error {
 				return nil
 			},
 			Action: func(c *cli.Context) error {
 				if len(c.Args()) == 0 {
-					cli.ShowCommandHelp(c, c.Command.Name)
+					if err := cli.ShowCommandHelp(c, c.Command.Name); err != nil {
+						return fmt.Errorf("Error while rendering command help: %v", err)
+					}
 					return fmt.Errorf("Missing argument")
 				}
 				s := &Server{}