Basic configuration

This patch introduces a basic on disk configuration, comprised of a main
configuration file and per-domain directories.

It's still not complete, but will be extended in subsequent patches.

internal/config/config.go

@@ -0,0 +1,60 @@
+// Package config implements the chasquid configuration.
+package config
+
+// Generate the config protobuf.
+//go:generate protoc --go_out=. config.proto
+
+import (
+	"io/ioutil"
+	"os"
+
+	"github.com/golang/glog"
+	"github.com/golang/protobuf/proto"
+)
+
+// Load the config from the given file.
+func Load(path string) (*Config, error) {
+	c := &Config{}
+
+	buf, err := ioutil.ReadFile(path)
+	if err != nil {
+		glog.Errorf("Failed to read config at %q", path)
+		glog.Errorf("  (%v)", err)
+		return nil, err
+	}
+
+	err = proto.UnmarshalText(string(buf), c)
+	if err != nil {
+		glog.Errorf("Error parsing config: %v", err)
+		return nil, err
+	}
+
+	// Fill in defaults for anything that's missing.
+
+	if c.Hostname == "" {
+		c.Hostname, err = os.Hostname()
+		if err != nil {
+			glog.Errorf("Could not get hostname: %v", err)
+			return nil, err
+		}
+	}
+
+	if c.MaxDataSizeMb == 0 {
+		c.MaxDataSizeMb = 50
+	}
+
+	if len(c.Address) == 0 {
+		c.Address = append(c.Address, "systemd")
+	}
+
+	logConfig(c)
+	return c, nil
+}
+
+func logConfig(c *Config) {
+	glog.Infof("Configuration:")
+	glog.Infof("  Hostname: %q", c.Hostname)
+	glog.Infof("  Max data size (MB): %d", c.MaxDataSizeMb)
+	glog.Infof("  Addresses: %v", c.Address)
+	glog.Infof("  Monitoring address: %s", c.MonitoringAddress)
+}