feat: Implement config parsing and start a server based on config

.gitignore

@@ -0,0 +1 @@
+config.json

config.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"os"
+)
+
+const configPath = "config.json"
+
+type config struct {
+	Port      int    `json:"port"`
+	ThemeName string `json:"theme"`
+}
+
+// createDefaultConfig checks if a config file is present. If not, it creates the default config file.
+// It returns true if a file is created.
+func createDefaultConfig() (bool, error) {
+	info, err := os.Stat(configPath)
+	if err == nil {
+		if info.IsDir() {
+			return false, errors.New("config.json is a directory")
+		}
+		return false, nil
+	}
+	if !os.IsNotExist(err) {
+		return false, err
+	}
+
+	// Create the file.
+	f, err := os.Create(configPath)
+	if err != nil {
+		return false, err
+	}
+	encoder := json.NewEncoder(f)
+	encoder.SetIndent("", "\t")
+	err = encoder.Encode(config{
+		Port:      80,
+		ThemeName: "default",
+	})
+	return true, err
+}
+
+// parseConfig parses the config file into a struct
+func parseConfig() (config, error) {
+	// Open the file.
+	f, err := os.Open(configPath)
+	if err != nil {
+		return config{}, err
+	}
+	defer f.Close()
+	// Decode it into the config struct.
+	var cfg config
+	err = json.NewDecoder(f).Decode(&cfg)
+	return cfg, err
+}

go.mod

@@ -2,4 +2,7 @@ module gitea.teamortix.com/Team-Ortix/blgo
 
 go 1.15
 
-require github.com/stretchr/testify v1.6.1
+require (
+	github.com/sirupsen/logrus v1.7.0
+	github.com/stretchr/testify v1.6.1
+)

go.sum

@@ -1,10 +1,17 @@
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+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/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/sirupsen/logrus v1.7.0 h1:ShrD1U9pZB12TX0cVy0DtePoCH97K8EtX+mg7ZARUtM=
+github.com/sirupsen/logrus v1.7.0/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193GlqGZbnPFnPV/5Rsb4=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -1,9 +1,31 @@
 package main
 
 import (
-	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/sirupsen/logrus"
 )
 
 func main() {
-	fmt.Print("zoop")
+	created, err := createDefaultConfig()
+	if err != nil {
+		logrus.Fatalf("error while reading config file: %v", err)
+	}
+	if created {
+		logrus.Info("The default config file has been created. Please edit it and re-run the program.")
+		return
+	}
+
+	cfg, err := parseConfig()
+	if err != nil {
+		logrus.Fatalf("error while parsing the config: %v", err)
+	}
+
+	portStr := strconv.Itoa(cfg.Port)
+	logrus.Info("Listening on port " + portStr)
+	err = http.ListenAndServe(":"+portStr, nil)
+	if err != nil {
+		logrus.Fatalf("error while listen and serving: %v", err)
+	}
 }