youtubebeat/vendor/github.com/elastic/beats/metricbeat/module/munin/munin.go

132 lines
3 KiB
Go

// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package munin
import (
"bufio"
"fmt"
"io"
"net"
"strconv"
"strings"
"time"
"github.com/joeshaw/multierror"
"github.com/pkg/errors"
"github.com/elastic/beats/libbeat/common"
)
const (
unknownValue = "U"
)
// Node connection
type Node struct {
conn net.Conn
writer io.Writer
reader *bufio.Reader
}
// Connect with a munin node
func Connect(address string, timeout time.Duration) (*Node, error) {
conn, err := net.DialTimeout("tcp", address, timeout)
if err != nil {
return nil, err
}
n := &Node{conn: conn,
writer: conn,
reader: bufio.NewReader(conn),
}
// Consume and ignore first line returned by munin, it is a comment
// about the node
scanner := bufio.NewScanner(n.reader)
scanner.Scan()
return n, scanner.Err()
}
// Close node connection releasing its resources
func (n *Node) Close() error {
return n.conn.Close()
}
// List of items exposed by the node
func (n *Node) List() ([]string, error) {
_, err := io.WriteString(n.writer, "list\n")
if err != nil {
return nil, err
}
scanner := bufio.NewScanner(n.reader)
scanner.Scan()
return strings.Fields(scanner.Text()), scanner.Err()
}
// Fetch metrics from munin node
func (n *Node) Fetch(items ...string) (common.MapStr, error) {
var errs multierror.Errors
event := common.MapStr{}
for _, item := range items {
_, err := io.WriteString(n.writer, "fetch "+item+"\n")
if err != nil {
errs = append(errs, err)
continue
}
scanner := bufio.NewScanner(n.reader)
scanner.Split(bufio.ScanWords)
for scanner.Scan() {
name := strings.TrimSpace(scanner.Text())
// Munin delimits metrics with a dot
if name == "." {
break
}
name = strings.TrimSuffix(name, ".value")
if !scanner.Scan() {
if scanner.Err() == nil {
errs = append(errs, errors.New("unexpected EOF when expecting value"))
}
break
}
value := scanner.Text()
key := fmt.Sprintf("%s.%s", item, name)
if value == unknownValue {
errs = append(errs, errors.Errorf("unknown value for %s", key))
continue
}
if f, err := strconv.ParseFloat(value, 64); err == nil {
event.Put(key, f)
continue
}
event.Put(key, value)
}
if scanner.Err() != nil {
errs = append(errs, scanner.Err())
}
}
return event, errs.Err()
}