Add config package basic funcs

config/config.go

@@ -0,0 +1,62 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/user"
+)
+
+type Config struct {
+	GithubToken string `json:"github_token"`
+	JiraToken   string `json:"jira_token"`
+}
+
+func getConfigPath() (string, error) {
+	user, err := user.Current()
+	if err != nil {
+		return "", err
+	}
+	return user.HomeDir + "/.campaigner", nil
+}
+
+func ReadConfig() (*Config, error) {
+	configPath, err := getConfigPath()
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := os.Stat(configPath); err != nil {
+		return nil, fmt.Errorf("cannot read campaigner config file: %w", err)
+	}
+
+	fileContents, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		return nil, fmt.Errorf("there was a problem reading the config file: %w", err)
+	}
+
+	var config Config
+	if err := json.Unmarshal(fileContents, &config); err != nil {
+		return nil, fmt.Errorf("there was a problem parsing the config file: %w", err)
+	}
+
+	return &config, nil
+}
+
+func SaveConfig(config *Config) error {
+	configPath, err := getConfigPath()
+	if err != nil {
+		return err
+	}
+
+	marshaledConfig, err := json.MarshalIndent(config, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	if err := ioutil.WriteFile(configPath, marshaledConfig, 0600); err != nil {
+		return fmt.Errorf("cannot save the config: %w", err)
+	}
+	return nil
+}