Default configuration, save to file, load from file

internal/config/configuration.go

@@ -1,20 +1,35 @@
 package config
 
 import (
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
+	"math/rand"
 	"os"
 	"path/filepath"
+	"strconv"
+
+	"github.com/OpenDroneMap/CloudODM/internal/fs"
+	"github.com/OpenDroneMap/CloudODM/internal/logger"
 
 	homedir "github.com/mitchellh/go-homedir"
 )
 
+var cfgPath string
+
+func NewConfiguration() Configuration {
+	conf := Configuration{}
+	conf.Nodes = map[string]Node{}
+	return conf
+}
+
 type Configuration struct {
-	nodes map[string]Node
+	Nodes map[string]Node `json:"nodes"`
 }
 
 type Node struct {
-	url   string
-	token string
+	Url   string `json:"url"`
+	Token string `json:"token"`
 }
 
 // Initialize the configuration
@@ -26,7 +41,66 @@ func Initialize() {
 		os.Exit(1)
 	}
 
-	cfgPath := filepath.Join(home, ".odm.json")
-	GetPublicNodes()
-	fmt.Println(cfgPath)
+	cfgPath = filepath.Join(home, ".odm.json")
+	if exists, _ := fs.FileExists(cfgPath); exists {
+		// Read existing config
+		loadFromFile()
+	} else {
+		// Download public nodes, choose a default
+		nodes := GetPublicNodes()
+		defaultConfig := NewConfiguration()
+
+		logger.Info("Found " + strconv.Itoa(len(nodes)) + " public nodes")
+
+		if len(nodes) > 0 {
+			logger.Info("Picking a random one...")
+
+			randomNode := nodes[rand.Intn(len(nodes))]
+
+			logger.Info("Setting default node to " + randomNode.String())
+			defaultConfig.Nodes["default"] = Node{Url: randomNode.Url, Token: ""}
+		}
+
+		saveToFile(defaultConfig)
+	}
+}
+
+func saveToFile(conf Configuration) {
+	jsonData, err := json.MarshalIndent(conf, "", " ")
+	if err != nil {
+		logger.Error(err)
+	}
+
+	jsonFile, err := os.Create(cfgPath)
+	if err != nil {
+		logger.Error(err)
+	}
+	defer jsonFile.Close()
+
+	jsonFile.Write(jsonData)
+
+	logger.Info("Wrote default configuration in " + cfgPath)
+}
+
+func loadFromFile() Configuration {
+	jsonFile, err := os.Open(cfgPath)
+	if err != nil {
+		logger.Error(err)
+	}
+	logger.Debug("Loaded configuration from " + cfgPath)
+
+	defer jsonFile.Close()
+
+	jsonData, err := ioutil.ReadAll(jsonFile)
+	if err != nil {
+		logger.Error("Cannot read configuration file: " + cfgPath)
+	}
+
+	conf := Configuration{}
+	err = json.Unmarshal([]byte(jsonData), &conf)
+	if err != nil {
+		logger.Error("Cannot parse configuration file: " + err.Error())
+	}
+
+	return conf
 }

internal/config/publicnodes.go

@@ -2,9 +2,9 @@ package config
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"net/http"
-	"strconv"
 
 	"github.com/OpenDroneMap/CloudODM/internal/logger"
 )
@@ -16,28 +16,31 @@ type PublicNode struct {
 	Website    string `json:"website"`
 }
 
+func (n PublicNode) String() string {
+	return fmt.Sprintf("%s", n.Url)
+}
+
 func GetPublicNodes() []PublicNode {
 	logger.Debug("Retrieving public nodes...")
+	nodes := []PublicNode{}
 
 	resp, err := http.Get("https://raw.githubusercontent.com/OpenDroneMap/CloudODM/master/public_nodes.json")
 	if err != nil {
 		logger.Info(err)
-		return nil
+		return nodes
 	}
 	defer resp.Body.Close()
 
 	body, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
 		logger.Info(err)
-		return nil
+		return nodes
 	}
 
-	nodes := []PublicNode{}
 	if err := json.Unmarshal(body, &nodes); err != nil {
 		logger.Info("Invalid JSON content: " + string(body))
-		return nil
+		return nodes
 	}
 
-	logger.Info("Loaded " + strconv.Itoa(len(nodes)) + " public nodes")
 	return nodes
 }

internal/fs/fs.go

@@ -0,0 +1,17 @@
+package fs
+
+import "os"
+
+// FileExists checks if a file path exists
+func FileExists(filePath string) (bool, error) {
+	exists := true
+	if _, err := os.Stat(filePath); err != nil {
+		if os.IsNotExist(err) {
+			exists = false
+		} else {
+			return false, err
+		}
+	}
+
+	return exists, nil
+}