1 files changed, 109 insertions, 0 deletions
diff --git a/lib/xdsconfig/configfile.go b/lib/xdsconfig/configfile.go
new file mode 100644
index 0000000..e3737f4
--- /dev/null
+++ b/lib/xdsconfig/configfile.go
@@ -0,0 +1,109 @@
+package xdsconfig
+
+import (
+	"encoding/json"
+	"os"
+	"path"
+
+	common "github.com/iotbzh/xds-common/golib"
+)
+
+type SyncThingConf struct {
+	BinDir     string `json:"binDir"`
+	Home       string `json:"home"`
+	GuiAddress string `json:"gui-address"`
+	GuiAPIKey  string `json:"gui-apikey"`
+}
+
+type XDSServerConf struct {
+	URL       string `json:"url"`
+	ConnRetry int    `json:"connRetry"`
+
+	// private/not exported fields
+	ID            string `json:"-"`
+	APIBaseURL    string `json:"-"`
+	APIPartialURL string `json:"-"`
+}
+
+type FileConfig struct {
+	HTTPPort    string          `json:"httpPort"`
+	WebAppDir   string          `json:"webAppDir"`
+	LogsDir     string          `json:"logsDir"`
+	XDSAPIKey   string          `json:"xds-apikey"`
+	ServersConf []XDSServerConf `json:"xdsServers"`
+	SThgConf    *SyncThingConf  `json:"syncthing"`
+}
+
+// readGlobalConfig reads configuration from a config file.
+// Order to determine which config file is used:
+//  1/ from command line option: "--config myConfig.json"
+//  2/ $HOME/.xds/agent/agent-config.json file
+//  3/ /etc/xds-agent/config.json file
+
+func readGlobalConfig(c *Config, confFile string) error {
+
+	searchIn := make([]string, 0, 3)
+	if confFile != "" {
+		searchIn = append(searchIn, confFile)
+	}
+	if homeDir := common.GetUserHome(); homeDir != "" {
+		searchIn = append(searchIn, path.Join(homeDir, ".xds", "agent", "agent-config.json"))
+	}
+
+	searchIn = append(searchIn, "/etc/xds-agent/agent-config.json")
+
+	var cFile *string
+	for _, p := range searchIn {
+		if _, err := os.Stat(p); err == nil {
+			cFile = &p
+			break
+		}
+	}
+	if cFile == nil {
+		c.Log.Infof("No config file found")
+		return nil
+	}
+
+	c.Log.Infof("Use config file: %s", *cFile)
+
+	// TODO move on viper package to support comments in JSON and also
+	// bind with flags (command line options)
+	// see https://github.com/spf13/viper#working-with-flags
+
+	fd, _ := os.Open(*cFile)
+	defer fd.Close()
+
+	// Decode config file content and save it in a first variable
+	fCfg := FileConfig{}
+	if err := json.NewDecoder(fd).Decode(&fCfg); err != nil {
+		return err
+	}
+
+	// Decode config file content and overwrite default settings
+	fd.Seek(0, 0)
+	json.NewDecoder(fd).Decode(&c.FileConf)
+
+	// Disable Syncthing support when there is no syncthing field in config
+	if fCfg.SThgConf == nil {
+		c.FileConf.SThgConf = nil
+	}
+
+	// Support environment variables (IOW ${MY_ENV_VAR} syntax) in agent-config.json
+	vars := []*string{
+		&c.FileConf.LogsDir,
+		&c.FileConf.WebAppDir,
+	}
+	if c.FileConf.SThgConf != nil {
+		vars = append(vars, &c.FileConf.SThgConf.Home,
+			&c.FileConf.SThgConf.BinDir)
+	}
+	for _, field := range vars {
+		var err error
+		*field, err = common.ResolveEnvVar(*field)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}