🐛 Fix error handling and logging

app/db/cassandra.go

@@ -1,10 +1,10 @@
 package db
 
 import (
-	"errors"
 	"log"
 	"sync"
 
+	"github.com/aykhans/oh-my-url/app/errors"
 	"github.com/aykhans/oh-my-url/app/utils"
 	"github.com/gocql/gocql"
 )
@@ -58,11 +58,11 @@ func (c *Cassandra) CreateURL(url string) (string, error) {
 	applied, err := c.db.Query(query, id, key, url, 0).Consistency(gocql.All).MapScanCAS(m)
 	if err != nil {
 		log.Println(err)
-		return "", err
+		return "", errors.ErrDBCreateURL
 	}
 	if !applied {
 		log.Println("Failed to insert unique key")
-		return "", errors.New("an error occurred, please try again later")
+		return "", errors.ErrDBCreateURL
 	}
 	c.currentID.ID = id
 
@@ -76,7 +76,11 @@ func (c *Cassandra) GetURL(key string) (string, error) {
 		Consistency(gocql.One).
 		Scan(&url)
 	if err != nil {
-		return "", err
+		log.Println(err)
+		if err == gocql.ErrNotFound {
+			return "", errors.ErrDBURLNotFound
+		}
+		return "", errors.ErrDBGetURL
 	}
 	return url, nil
 }

app/db/postgres.go

@@ -1,6 +1,9 @@
 package db
 
 import (
+	"log"
+
+	"github.com/aykhans/oh-my-url/app/errors"
 	"gorm.io/gorm"
 )
 
@@ -9,10 +12,10 @@ type Postgres struct {
 }
 
 type url struct {
-	ID  uint   `gorm:"primaryKey"`
+	ID    uint   `gorm:"primaryKey"`
-	Key string `gorm:"unique;not null;size:15;default:null"`
+	Key   string `gorm:"unique;not null;size:15;default:null"`
-	URL string `gorm:"not null;default:null"`
+	URL   string `gorm:"not null;default:null"`
-	Count int `gorm:"not null;default:0"`
+	Count int    `gorm:"not null;default:0"`
 }
 
 func (p *Postgres) Init() {
@@ -30,7 +33,8 @@ func (p *Postgres) CreateURL(mainUrl string) (string, error) {
 	url := url{URL: mainUrl}
 	tx := p.gormDB.Create(&url)
 	if tx.Error != nil {
-		return "", tx.Error
+		log.Println(tx.Error)
+		return "", errors.ErrDBCreateURL
 	}
 	return url.Key, nil
 }
@@ -39,7 +43,11 @@ func (p *Postgres) GetURL(key string) (string, error) {
 	var result url
 	tx := p.gormDB.Where("key = ?", key).First(&result)
 	if tx.Error != nil {
-		return "", tx.Error
+		log.Println(tx.Error)
+		if tx.Error == gorm.ErrRecordNotFound {
+			return "", errors.ErrDBURLNotFound
+		}
+		return "", errors.ErrDBGetURL
 	}
 	result.Count++
 	p.gormDB.Save(&result)

app/errors/api.go

@@ -0,0 +1,9 @@
+package errors
+
+import "errors"
+
+var (
+	ErrAPITemplateParsing = errors.New("an error occured while parsing template please try again later")
+	ErrAPIInvalidURL      = errors.New("invalid URL")
+	ErrAPI503             = errors.New("service unavailable please try again later")
+)

app/errors/db.go

@@ -0,0 +1,9 @@
+package errors
+
+import "errors"
+
+var (
+	ErrDBCreateURL   = errors.New("an error occured please try again later")
+	ErrDBGetURL      = errors.New("an error occured please try again later")
+	ErrDBURLNotFound = errors.New("url not found")
+)

app/http_handlers/base.go

@@ -23,3 +23,8 @@ func InternalServerError(w http.ResponseWriter, err error) {
 	log.Fatal(err)
 	http.Error(w, "Internal Server Error", http.StatusInternalServerError)
 }
+
+func Error503(w http.ResponseWriter, err error) {
+	log.Println(err)
+	http.Error(w, "Service Unavailable", http.StatusServiceUnavailable)
+}

app/http_handlers/url_create.go

@@ -1,18 +1,21 @@
 package httpHandlers
 
 import (
-	"github.com/aykhans/oh-my-url/app/utils"
-	"github.com/aykhans/oh-my-url/app/config"
 	"html/template"
+	"log"
 	"net/http"
 	netUrl "net/url"
 	"regexp"
+
+	"github.com/aykhans/oh-my-url/app/config"
+	"github.com/aykhans/oh-my-url/app/errors"
+	"github.com/aykhans/oh-my-url/app/utils"
 )
 
 type CreateData struct {
 	ShortedURL string
 	MainURL    string
-	Error      string
+	Error      error
 }
 
 func (hl *HandlerCreate) UrlCreate(w http.ResponseWriter, r *http.Request) {
@@ -23,7 +26,8 @@ func (hl *HandlerCreate) UrlCreate(w http.ResponseWriter, r *http.Request) {
 
 	tmpl, err := template.ParseFiles(utils.GetTemplatePaths("index.html")...)
 	if err != nil {
-		InternalServerError(w, err)
+		log.Println(err)
+		InternalServerError(w, errors.ErrAPITemplateParsing)
 		return
 	}
 
@@ -31,7 +35,8 @@ func (hl *HandlerCreate) UrlCreate(w http.ResponseWriter, r *http.Request) {
 	case http.MethodGet:
 		err = tmpl.Execute(w, nil)
 		if err != nil {
-			InternalServerError(w, err)
+			log.Println(err)
+			InternalServerError(w, errors.ErrAPITemplateParsing)
 			return
 		}
 	case http.MethodPost:
@@ -41,23 +46,33 @@ func (hl *HandlerCreate) UrlCreate(w http.ResponseWriter, r *http.Request) {
 		if !isValidUrl {
 			data := CreateData{
 				MainURL: url,
-				Error:   "Invalid URL",
+				Error:   errors.ErrAPIInvalidURL,
 			}
 			err = tmpl.Execute(w, data)
 			if err != nil {
-				InternalServerError(w, err)
+				log.Println(err)
+				InternalServerError(w, errors.ErrAPITemplateParsing)
 			}
 			return
 		}
 
 		key, err := hl.DB.CreateURL(url)
 		if err != nil {
-			InternalServerError(w, err)
+			data := CreateData{
+				MainURL: url,
+				Error:   errors.ErrAPI503,
+			}
+			err = tmpl.Execute(w, data)
+			if err != nil {
+				log.Println(err)
+				InternalServerError(w, errors.ErrAPITemplateParsing)
+			}
 			return
 		}
 		shortedURL, err := netUrl.JoinPath(config.GetForwardDomain(), key)
 		if err != nil {
-			InternalServerError(w, err)
+			log.Println(err)
+			InternalServerError(w, errors.ErrAPITemplateParsing)
 			return
 		}
 		data := CreateData{
@@ -66,7 +81,8 @@ func (hl *HandlerCreate) UrlCreate(w http.ResponseWriter, r *http.Request) {
 		}
 		err = tmpl.Execute(w, data)
 		if err != nil {
-			InternalServerError(w, err)
+			log.Println(err)
+			InternalServerError(w, errors.ErrAPITemplateParsing)
 			return
 		}
 

app/main.go

@@ -1,11 +1,13 @@
 package main
 
 import (
+	"log"
+	"net/http"
+	"sync"
+
 	"github.com/aykhans/oh-my-url/app/config"
 	"github.com/aykhans/oh-my-url/app/db"
 	"github.com/aykhans/oh-my-url/app/http_handlers"
-	"net/http"
-	"sync"
 )
 
 func main() {
@@ -27,11 +29,25 @@ func main() {
 	wg.Add(2)
 	go func() {
 		defer wg.Done()
-		panic(http.ListenAndServe(":"+appConfig.LISTEN_PORT_CREATE, urlCreateMux))
+		for {
+			err := http.ListenAndServe(":"+appConfig.LISTEN_PORT_CREATE, urlCreateMux)
+			if err != nil {
+				log.Println(err)
+				continue
+			}
+			break
+		}
 	}()
 	go func() {
 		defer wg.Done()
-		panic(http.ListenAndServe(":"+appConfig.LISTEN_PORT_FORWARD, urlReadMux))
+		for {
+			err := http.ListenAndServe(":"+appConfig.LISTEN_PORT_FORWARD, urlReadMux)
+			if err != nil {
+				log.Println(err)
+				continue
+			}
+			break
+		}
 	}()
 	wg.Wait()
 }

app/templates/index.html

@@ -93,7 +93,7 @@
     <h1>Oh My URL!</h1>
     <form action="/" method="post">
       {{ if .Error }}
-        <label for="urlInput" style="color: red;">{{ .Error }}</label>
+        <label for="urlInput" style="color: red;">{{ .Error.Error }}</label>
       {{ end }}
       <input type="url" id="urlInput" name="url" placeholder="https://example.com/" value="{{ if .MainURL }}{{ .MainURL }}{{ end }}" required>
       {{ if .ShortedURL }}