Crimson client: created add-host and query-host

go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go

Index: go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go
diff --git a/go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go b/go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go
index ddb50ad060b6cce6157583f07f44ae3e1d10e7b4..23e55e91fabd91d861fbd4bda64a34c56fb0c62b 100644
--- a/go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go
+++ b/go/src/infra/crimson/cmd/cmdhelper/cmdhelper.go
@@ -342,3 +342,44 @@ func PrintIPRange(ipRanges []*crimson.IPRange, format FormatType) {
 		fmt.Println(s)
 	}
 }
+
+// FormatHostList formats a list of hosts for pretty-printing.
+func FormatHostList(hostList *crimson.HostList, format FormatType) ([]string, error) {
+	var formatter Formatter
+
+	switch format {
+	case jsonFormat:
+		jsonBytes, err := json.Marshal(hostList.Hosts)

[Vadim Sh., 2016/06/30 23:58:12]

nit: consider using https://golang.org/pkg/encoding/json/#MarshalIndent instead
(with indent == "  "). Otherwise it may be too dense.

[pgervais, 2016/07/01 01:01:00]

Done.

+		if err != nil {
+			return []string{}, err
+		}
+		return []string{string(jsonBytes)}, nil
+	case textFormat:
+		formatter = &TextFormatter{}
+	case csvFormat:
+		formatter = &CSVFormatter{}
+	}
+	rows := [][]string{{"mac", "ip", "site", "hostname", "class"}}
+	for _, host := range hostList.Hosts {
+		rows = append(rows, []string{
+			fmt.Sprintf("%s", host.MacAddr),
+			fmt.Sprintf("%s", host.Ip),
+			fmt.Sprintf("%s", host.Site),
+			fmt.Sprintf("%s", host.Hostname),
+			fmt.Sprintf("%s", host.BootClass),
+		})
+	}
+	return formatter.FormatRows(rows), nil
+}
+
+// PrintHostList pretty-prints a list of hosts.
+func PrintHostList(hostList *crimson.HostList, format FormatType) {
+	lines, err := FormatHostList(hostList, format)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "ERROR: %s", err)
+		return
+	}
+	for _, s := range lines {
+		fmt.Println(s)
+	}
+}