1 files changed, 72 insertions, 0 deletions
diff --git a/config/config.go b/config/config.go
new file mode 100644
index 0000000..5463c5f
--- /dev/null
+++ b/config/config.go
@@ -0,0 +1,72 @@
+package config
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+)
+
+// ControlUser is used for various DTail specific operations.
+const ControlUser string = "DTAIL-CONTROL-USER"
+
+// Client holds a DTail client configuration.
+var Client *ClientConfig
+
+// Server holds a DTail server configuration.
+var Server *ServerConfig
+
+// Common holds common configs of both both, client and server.
+var Common *CommonConfig
+
+// Used to initialize the configuration.
+type configInitializer struct {
+	Common *CommonConfig
+	Server *ServerConfig
+	Client *ClientConfig
+}
+
+// Parse and read a given config file in JSON format.
+func (c *configInitializer) parseConfig(configFile string) {
+	fd, err := os.Open(configFile)
+	if err != nil {
+		panic(err)
+	}
+	defer fd.Close()
+
+	cfgBytes, err := ioutil.ReadAll(fd)
+	if err != nil {
+		panic(err)
+	}
+
+	err = json.Unmarshal([]byte(cfgBytes), c)
+	if err != nil {
+		panic(err)
+	}
+}
+
+// Init the DTail configuration.
+func Init(configFile string) {
+	initializer := configInitializer{
+		Common: newDefaultCommonConfig(),
+		Server: newDefaultServerConfig(),
+		Client: newDefaultClientConfig(),
+	}
+
+	if configFile == "" {
+		configFile = "./cfg/dtail.json"
+	}
+
+	if _, err := os.Stat(configFile); !os.IsNotExist(err) {
+		initializer.parseConfig(configFile)
+	}
+
+	// Assign pointers to global variables, so that we can access the
+	// configuration from any place of the program.
+	Common = initializer.Common
+	Server = initializer.Server
+	Client = initializer.Client
+
+	if Server.MapreduceLogFormat == "" {
+		Server.MapreduceLogFormat = "default"
+	}
+}