Extract bind statistics parsing in sub-packages

This prepares the addition of statistics v3 parsing.

bind/v2/v2.go

@@ -0,0 +1,79 @@
+package v2
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/digitalocean/bind_exporter/bind"
+)
+
+// Client implements bind.Client and can be used to query a BIND v2 API.
+type Client struct {
+	url  string
+	http *http.Client
+}
+
+// NewClient returns an initialized Client.
+func NewClient(url string, c *http.Client) *Client {
+	return &Client{
+		url:  url,
+		http: c,
+	}
+}
+
+// Stats implements bind.Stats.
+func (c *Client) Stats() (bind.Statistics, error) {
+	s := bind.Statistics{}
+
+	resp, err := c.http.Get(c.url)
+	if err != nil {
+		return s, fmt.Errorf("error querying stats: %s", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return s, fmt.Errorf("failed to read response: %s", err)
+	}
+
+	root := Isc{}
+	if err := xml.Unmarshal([]byte(body), &root); err != nil {
+		return s, fmt.Errorf("Failed to unmarshal XML response: %s", err)
+	}
+
+	stats := root.Bind.Statistics
+	for _, t := range stats.Server.QueriesIn.Rdtype {
+		s.Server.IncomingQueries = append(s.Server.IncomingQueries, stat(t))
+	}
+	for _, t := range stats.Server.Requests.Opcode {
+		s.Server.IncomingRequests = append(s.Server.IncomingRequests, stat(t))
+	}
+	for _, t := range stats.Server.NsStats {
+		s.Server.NSStats = append(s.Server.NSStats, stat(t))
+	}
+	for _, view := range stats.Views {
+		v := bind.View{Name: view.Name}
+		for _, t := range view.Cache {
+			v.Cache = append(v.Cache, stat(t))
+		}
+		for _, t := range view.Rdtype {
+			v.ResolverQueries = append(v.ResolverQueries, stat(t))
+		}
+		for _, t := range view.Resstat {
+			v.ResolverStats = append(v.ResolverStats, stat(t))
+		}
+		s.Views = append(s.Views, v)
+	}
+	s.TaskManager = stats.Taskmgr
+
+	return s, nil
+}
+
+func stat(s Stat) bind.Stat {
+	return bind.Stat{
+		Name:    s.Name,
+		Counter: s.Counter,
+	}
+}