lld.go

/*
 * g2z - Zabbix module adapter for Go
 * Copyright (C) 2015 - Ryan Armstrong <ryan@cavaliercoder.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package g2z

import (
	"bytes"
	"regexp"
	"strings"
)

// DiscoveryData is a slice of DiscoveryItems which is returned for registered discovery rules
// as a JSON encoded string.
type DiscoveryData []DiscoveryItem

// DiscoveryItem is a map of key/value pairs that represents a single instance of a discovered
// asset.
type DiscoveryItem map[string]string

// macroIllegalPattern is a regular expression pattern matching characters which are illegal in a
// Zabbix discovery macro name.
var macroIllegalPattern = regexp.MustCompile(`[^A-Z0-9_]+`)

// Json converts a DiscoveryData struct into a JSON encoded string, compatible with Zabbix
// Low-Level discovery rules from v2.2.0 and above.
func (c DiscoveryData) Json() string {
	b := bytes.Buffer{}

	b.WriteString("{\n\t\"data\":[")

	for i, item := range c {
		if i > 0 {
			b.WriteString(",")
		}

		b.WriteString("\n\t{")

		firstMacro := true
		for macro, val := range item {
			if firstMacro {
				firstMacro = false
			} else {
				b.WriteString(",")
			}

			b.WriteString("\n\t\t\"{#")
			b.WriteString(macroName(macro))
			b.WriteString("}\":\"")
			b.WriteString(jsonEscape(val))
			b.WriteString("\"")
		}

		b.WriteString("}")
	}

	b.WriteString("]}")

	return b.String()
}

// escape JSON values to prevent invalidating discovery response body
func jsonEscape(a string) string {
	return strings.Replace(a, "\"", "\\\"", -1)
}

// format a name string as a discovery macro (E.g `{#MY_MACRO}`)
func macroName(name string) string {
	name = strings.ToUpper(name)
	name = strings.Replace(name, " ", "_", -1)
	name = macroIllegalPattern.ReplaceAllString(name, "")
	return name
}