More features (#9)

* added config file implementation, refactoring
* add gitignore
* improved test
* preperations for more metrics
* added resource metrics
* added first bgp metrics
* added asn as label for bgp metrics
* added prefix and message counts to bgp metrics
* simplified
* Update README.md
* added yaml dependency
* fixed go routine call
* added timeout
* clean up
* added TLS support
* set default api port for TLS
* added routes metric
* added missing log information
* added type collectorContext to reduce the count of parameters for better readability
* added DHCP and DHCPv6 metrics
* filter for active dhcp leases only
* added pool metrics
* enable/disable feature in config file
* refactoring

* clean up

* comment fix

config/config.go

@@ -7,10 +7,19 @@ import (
 	yaml "gopkg.in/yaml.v2"
 )
 
+// Config represents the configuration for the exporter
 type Config struct {
-	Devices []Device `yaml:"devices"`
+	Devices  []Device `yaml:"devices"`
+	Features struct {
+		BGP    bool `yaml:"bgp,omitempty"`
+		DHCP   bool `yaml:"dhcp,omitempty"`
+		DHCPv6 bool `yaml:"dhcpv6,omitempty"`
+		Routes bool `yaml:"routes,omitempty"`
+		Pools  bool `yaml:"pools,omitempty"`
+	} `yaml:"features,omitempty"`
 }
 
+// Device represents a target device
 type Device struct {
 	Name     string `yaml:"name"`
 	Address  string `yaml:"address"`
@@ -18,6 +27,7 @@ type Device struct {
 	Password string `yaml:"password"`
 }
 
+// Load reads YAML from reader and unmashals in Config
 func Load(r io.Reader) (*Config, error) {
 	b, err := ioutil.ReadAll(r)
 	if err != nil {