config.go

/*
  Copyright (c) 2014, Mike 'Fuzzy' Partin <[email protected]>
  All rights reserved.

  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice, this
     list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"regexp"
	"strings"
)

type Target struct {
	CarbonPrefix string `json:"carbon_prefix"`
	Hostname     string `json:"hostname"`
	Tables       []struct {
		Name       string `json:"name"`
		BaseOid    string `json:"base_oid"`
		LabelOid   int    `json:"label_oid"`
		OidEntries []struct {
			Oid  int    `json:"oid"`
			Path string `json:"path"`
		} `json:"entries"`
	} `json:"tables"`
	Metrics []struct {
		Oid  string `json:"oid"`
		Path string `json:"path"`
	}
}

type Config struct {
	Daemonize    bool   `json:"daemonize"`
	LogDir       string `json:"log_dir"`
	CfgDir       string `json:"cfg_dir"`
	LogName      string `json:"log_name"`
	Community    string `json:"snmp_community"`
	CarbonHost   string `json:"carbon_host"`
	CarbonPort   int    `json:"carbon_port"`
	CarbonPrefix string `json:"carbon_prefix"`
	Targets      []Target
}

func readFile(fpath string) []byte {
	// define our return variable
	var data []byte

	// and our comment syntax
	comments := regexp.MustCompile("//.*$")

	// and our file descriptor
	fp, err := os.Open(fpath)
	if err != nil {
		panic(err)
	}

	// and finally our line by line scanner
	scanner := bufio.NewScanner(fp)

	// now let's get to processing
	for scanner.Scan() {
		// strip all whitespace, and comments
		line := comments.ReplaceAllString(strings.TrimSpace(scanner.Text()), "")
		// store all valid data in our return variable
		for _, c := range line {
			data = append(data[:], byte(c))
		}
	}

	// one last status check
	err = scanner.Err()
	if err != nil {
		panic(err)
	}

	// and return
	return data
}

func ReadConfig(jsonCfg string) Config {
	// declare our return variable
	var cfg Config

	// read in our config and unmarshal it, or die tryin
	err := json.Unmarshal(readFile(jsonCfg), &cfg)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Polling SNMP Community: %s\n", cfg.Community)
	fmt.Printf("Using graphite instance at: %s:%d\n", cfg.CarbonHost, cfg.CarbonPort)

	dir, er := ioutil.ReadDir(cfg.CfgDir)
	if er != nil {
		panic(er)
	} else {
		for key := range dir {
			if strings.HasSuffix(dir[key].Name(), ".json") {
				fmt.Printf("Reading: %s/%s\n", cfg.CfgDir, dir[key].Name())
				var tCfg Target
				err = json.Unmarshal(readFile(fmt.Sprintf("%s/%s", cfg.CfgDir, dir[key].Name())), &tCfg)
				if err != nil {
					panic(err)
				}
				cfg.Targets = append(cfg.Targets, tCfg)
			}
		}
	}

	return cfg
}

corp-access01.json

{
		// 
		"hostname": "corp-access01.corp.theplatform.com",
		"carbon_prefix": "corp-access01",
		"tables": [
				{
						"name": "ports",
						"base_oid": "1.3.6.1.2.1.2.2.1",
						"label_oid": 2,
						"entries": [
								{"oid": 10, "path": "octets.in"},
								{"oid": 16, "path": "octets.out"},
								{"oid": 14, "path": "errors.in"},
								{"oid": 20, "path": "errors.out"}
						]
				}
		],
		"metrics": [
				{"oid": "1.2.3.4.5.6.7.8.9.10", "path": "specific.metric.path"}
		]
}

s2g.json

{
		// As a quick note on syntax, this is a comment...

		// This has no effect at current, but will....oh yes, and soon
		"daemonize": true,
		// This is kind of in the same boat
		"log_dir": "/Users/fuzzy/s2g/log",
		// This however should point to a directory where you will keep config files
		// on a per host basis. Any file in this directory with the extension '.json'
		// will be read in.
		"cfg_dir": "/Users/fuzzy/s2g/etc/s2g.d",
		// This is currently set as a global option, but I will be moving it to the
		// host configs at some point, with the global option only set as a default.
		"snmp_community": "tPnet0ps",
		// Where should I shove my metrics
		"carbon_host": "192.168.106.34",
		"carbon_port": 2003,
		// All our metric paths should begin with:
		"carbon_prefix": "network"
}