feat: added server configuration using env vars (#7)

* feat: added server configuration using env vars

* updated readme

* refactor: removed error returns where unneeded

README.md

@@ -2,35 +2,60 @@
 
 A service/library to extract product information from URLs.
 
+## Configuration
+
+| Variable name  | Default | Description                    |
+| -------------- | ------- | ------------------------------ |
+| `HTTP_ENABLED` | `true`  | Enable/Disable the HTTP server |
+| `HTTP_PORT`    | `8080`  | Port to serve the HTTP in      |
+
+## Servers
+
+### HTTP
+
+- `POST /item`
+
+  Parameters:
+  - **url**: The URL to extract information from
+
+  Responses:
+  - `200`: Information extracted
+  - `400`: Shop not supported, missing parameters
+  - `500`: Internal error, check logs
+
+
+- `GET /liveness`
+
+  Responses:
+  - `200`: Server running
+
+
 ## Data model
 
 Currently, this information is extracted from the site (if possbile):
 
 ``` js
 {
-    "image_url": "<url>", // (string) URL to an image file
-    "in_stock": false, // (bool) If the item is currently available for purchase
-    "name": "<name>", // (string) The name of the product as it appears on the site
-    "price": 14.21, // (optional, float) The price of the product [parsed by the library]
-    "price_text": "14,21 €", // (optional, string) The price of the product as it appears on the site (with currency)
-    "release_date": "2021-03-22T00:00:00Z", // (optional, string RFC3339) the release date of the item
-    "url": "<url>" // (string) The URL of the item
+    "description": "...",
+    "image_url": "https://...",
+    "in_stock": false,
+    "name": "...",
+    "price": 0.0,
+    "price_text": "0,0 €",
+    "release_date": "2019-03-08T00:00:00Z",
+    "url": "https://..."
 }
 ```
 
+[pkg/models/product.go](./pkg/models/product.go)
+
 ## Supported sites
 
 Support is handled in a _best effort_ basis. Some sites do not provided all exposed fields.
 
 - [Amazon.es](https://amazon.es)
 - [Amazon.com](https://amazon.com)
-- [Akira Comics](https://www.akiracomics.com)
+- [AkiraComics](https://www.akiracomics.com)
 - [Casa del libro](https://www.casadellibro.com)
 - [Heroes De Papel](https://heroesdepapel.es)
 - [Steam](https://store.steampowered.com)
-
-## Running
-
-```
-go run cmd/server/main.go
-```

cmd/bazaar/main.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"context"
+	"log"
+
 	"github.com/fmartingr/bazaar/internal/server"
 	"github.com/fmartingr/bazaar/pkg/manager"
 	"github.com/fmartingr/bazaar/pkg/shop/akiracomics"
@@ -20,11 +23,13 @@ func main() {
 	m.Register(gtmstore.Domains, gtmstore.NewGTMStoreShopFactory())
 	m.Register(casadellibro.Domains, casadellibro.NewCasaDelLibroShopFactory())
 
-	server := server.NewServer(server.ServerConf{
-		HttpPort: 8080,
-	}, &m)
+	ctx := context.Background()
 
-	server.Start()
+	server := server.NewServer(server.ParseServerConfiguration(ctx), &m)
+
+	if err := server.Start(ctx); err != nil {
+		log.Panicf("error starting server: %s", err)
+	}
 
 	server.WaitStop()
 }

go.mod

@@ -5,6 +5,7 @@ go 1.19
 require (
 	github.com/PuerkitoBio/goquery v1.8.0
 	github.com/goodsign/monday v1.0.0
+	github.com/sethvargo/go-envconfig v0.8.2
 	github.com/stretchr/testify v1.8.0
 )
 

go.sum

@@ -7,8 +7,11 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/goodsign/monday v1.0.0 h1:Yyk/s/WgudMbAJN6UWSU5xAs8jtNewfqtVblAlw0yoc=
 github.com/goodsign/monday v1.0.0/go.mod h1:r4T4breXpoFwspQNM+u2sLxJb2zyTaxVGqUfTBjWOu8=
+github.com/google/go-cmp v0.5.8 h1:e6P7q2lk1O+qJJb4BtCQXlK8vWEO8V1ZeuEdJNOqZyg=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sethvargo/go-envconfig v0.8.2 h1:DDUVuG21RMgeB/bn4leclUI/837y6cQCD4w8hb5797k=
+github.com/sethvargo/go-envconfig v0.8.2/go.mod h1:Iz1Gy1Sf3T64TQlJSvee81qDhf7YIlt8GMUX6yyNFs0=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=

internal/server/config.go

@@ -0,0 +1,64 @@
+package server
+
+import (
+	"bufio"
+	"context"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/sethvargo/go-envconfig"
+)
+
+// readDotEnv reads the configuration from variables in a .env file (only for contributing)
+func readDotEnv() map[string]string {
+	file, err := os.Open(".env")
+	if err != nil {
+		return nil
+	}
+	defer file.Close()
+
+	result := make(map[string]string)
+
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		keyval := strings.SplitN(line, "=", 2)
+		result[keyval[0]] = keyval[1]
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+
+	return result
+}
+
+type ServerConfig struct {
+	Hostname string `env:"HOSTNAME,required"`
+	Http     struct {
+		Enabled bool `env:"HTTP_ENABLED,default=True"`
+		Port    int  `env:"HTTP_PORT,default=8080"`
+	}
+}
+
+func ParseServerConfiguration(ctx context.Context) *ServerConfig {
+	var cfg ServerConfig
+
+	lookuper := envconfig.MultiLookuper(
+		envconfig.MapLookuper(map[string]string{"HOSTNAME": os.Getenv("HOSTNAME")}),
+		envconfig.MapLookuper(readDotEnv()),
+		envconfig.PrefixLookuper("BAZAAR_", envconfig.OsLookuper()),
+		envconfig.OsLookuper(),
+	)
+	if err := envconfig.ProcessWith(ctx, &cfg, lookuper); err != nil {
+		log.Fatalf("Error parsing configuration: %s", err)
+	}
+
+	return &cfg
+}

internal/server/http.go

@@ -50,7 +50,9 @@ func NewHttpServer(port int, m *manager.Manager) *httpServer {
 		payload, _ := json.Marshal(product)
 
 		rw.Header().Add("Content-Type", "application/json")
-		rw.Write(payload)
+		if _, err := rw.Write(payload); err != nil {
+			log.Printf("error writting response: %s", err)
+		}
 	})
 
 	mux.HandleFunc("/liveness", func(w http.ResponseWriter, r *http.Request) {

internal/server/server.go

@@ -14,54 +14,58 @@ import (
 	"github.com/fmartingr/bazaar/pkg/manager"
 )
 
-type ServerConf struct {
-	HttpPort int
-}
-
 type Server struct {
-	http internalModels.Server
+	Http   internalModels.Server
+	config *ServerConfig
 
 	cancel context.CancelFunc
 }
 
-func (s *Server) Start() error {
-	ctx, cancel := context.WithCancel(context.Background())
+func (s *Server) Start(ctx context.Context) error {
+	ctx, cancel := context.WithCancel(ctx)
 	s.cancel = cancel
 
-	go func() {
-		if err := s.http.Start(ctx); err != nil && !errors.Is(err, http.ErrServerClosed) {
-			log.Fatalf("error starting server: %s", err)
-		}
-	}()
+	if s.config.Http.Enabled {
+		go func() {
+			if err := s.Http.Start(ctx); err != nil && !errors.Is(err, http.ErrServerClosed) {
+				log.Fatalf("error starting server: %s", err)
+			}
+		}()
+	}
 
 	return nil
 }
 
-func (s *Server) WaitStop() error {
+func (s *Server) WaitStop() {
 	signals := make(chan os.Signal, 1)
 	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
 
 	sig := <-signals
 	log.Printf("signal %s received, shutting down", sig)
 
-	return s.Stop()
+	s.Stop()
 }
 
-func (s *Server) Stop() error {
+func (s *Server) Stop() {
 	s.cancel()
 
 	shuwdownContext, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	if err := s.http.Stop(shuwdownContext); err != nil && !errors.Is(err, http.ErrServerClosed) {
-		log.Fatalf("error shutting down http server: %s", err)
-	}
-
-	return nil
-}
-
-func NewServer(serverConf ServerConf, m *manager.Manager) *Server {
-	return &Server{
-		http: NewHttpServer(serverConf.HttpPort, m),
+	if s.config.Http.Enabled {
+		if err := s.Http.Stop(shuwdownContext); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			log.Fatalf("error shutting down http server: %s", err)
+		}
 	}
 }
+
+func NewServer(conf *ServerConfig, m *manager.Manager) *Server {
+	server := &Server{
+		config: conf,
+	}
+	if conf.Http.Enabled {
+		server.Http = NewHttpServer(conf.Http.Port, m)
+	}
+
+	return server
+}

pkg/manager/main.go

@@ -14,19 +14,15 @@ type Manager struct {
 	domains map[string]models.Shop
 }
 
-func (m *Manager) Register(domains []string, shopFactory models.ShopFactory) error {
+func (m *Manager) Register(domains []string, shopFactory models.ShopFactory) {
 	baseShop := models.NewShopOptions(clients.NewBasicHttpClient())
 	shop := shopFactory(baseShop)
 
 	for _, domain := range domains {
-		if _, exists := m.domains[domain]; exists {
-			return fmt.Errorf("domain %s is already registered", domain)
-		} else {
+		if _, exists := m.domains[domain]; !exists {
 			m.domains[domain] = shop
 		}
 	}
-
-	return nil
 }
 
 func (m *Manager) GetShop(host string) models.Shop {