forked from remeh/go-rrd
-
Notifications
You must be signed in to change notification settings - Fork 0
/
client.go
170 lines (145 loc) · 3.79 KB
/
client.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
// Package rrd provides a client which can talk to rrdtool's rrdcached
// It supports all known commands and uses native golang types where
// appropriate.
package rrd
import (
"bufio"
"fmt"
"io"
"net"
"regexp"
"strconv"
"strings"
"time"
)
const (
// DefaultPort is the default rrdcached port.
DefaultPort = 42217
)
var (
respRe = regexp.MustCompile(`^(-?\d+)\s+(.*)$`)
// DefaultTimeout is the default read / write / dial timeout for Clients.
DefaultTimeout = time.Second * 10
)
// Client is a rrdcached client.
type Client struct {
conn net.Conn
addr string
network string
timeout time.Duration
scanner *bufio.Scanner
}
// Timeout sets read / write / dial timeout for a rrdcached Client.
func Timeout(timeout time.Duration) func(*Client) error {
return func(c *Client) error {
c.timeout = timeout
return nil
}
}
// Unix sets the client to use a unix socket.
func Unix(c *Client) error {
c.network = "unix"
return nil
}
// NewClient returns a new rrdcached client connected to addr.
// By default addr is treated as a TCP address to use UNIX sockets pass Unix as an option.
// If addr for a TCP address doesn't include a port the DefaultPort will be used.
func NewClient(addr string, options ...func(c *Client) error) (*Client, error) {
c := &Client{timeout: DefaultTimeout, network: "tcp", addr: addr}
for _, f := range options {
if f == nil {
return nil, ErrNilOption
}
if err := f(c); err != nil {
return nil, err
}
}
if c.network == "tcp" {
if !strings.Contains(c.addr, ":") {
c.addr = fmt.Sprintf("%v:%v", c.addr, DefaultPort)
}
}
var err error
if c.conn, err = net.DialTimeout(c.network, c.addr, c.timeout); err != nil {
return nil, err
}
c.scanner = bufio.NewScanner(bufio.NewReader(c.conn))
c.scanner.Split(bufio.ScanLines)
return c, nil
}
// setDeadline updates the deadline on the connection based on the clients configured timeout.
func (c *Client) setDeadline() error {
return c.conn.SetDeadline(time.Now().Add(c.timeout))
}
// Exec executes cmd on the server and returns the response.
func (c *Client) Exec(cmd string) ([]string, error) {
return c.ExecCmd(NewCmd(cmd))
}
// ExecCmd executes cmd on the server and returns the response.
func (c *Client) ExecCmd(cmd *Cmd) ([]string, error) {
if err := c.setDeadline(); err != nil {
return nil, err
}
if _, err := c.conn.Write([]byte(cmd.String())); err != nil {
return nil, err
}
if err := c.setDeadline(); err != nil {
return nil, err
}
if !c.scanner.Scan() {
return nil, c.scanErr()
}
l := c.scanner.Text()
matches := respRe.FindStringSubmatch(l)
if len(matches) != 3 {
return nil, NewInvalidResponseError("bad header", l)
}
cnt, err := strconv.Atoi(matches[1])
if err != nil {
// This should be impossible given the regexp matched.
return nil, NewInvalidResponseError("bad header count", l)
}
switch {
case cnt < 0:
// rrdcached reported an error.
return nil, NewError(cnt, matches[2])
case cnt == 0:
// message is the line e.g. first.
return []string{matches[2]}, nil
}
if err := c.setDeadline(); err != nil {
return nil, err
}
lines := make([]string, 0, cnt)
for len(lines) < cnt && c.scanner.Scan() {
lines = append(lines, c.scanner.Text())
if err := c.setDeadline(); err != nil {
return nil, err
}
}
if len(lines) != cnt {
// Short response.
return nil, c.scanErr()
}
return lines, nil
}
// Close closes the connection to the server.
func (c *Client) Close() error {
errD := c.setDeadline()
_, errW := c.conn.Write([]byte("quit"))
err := c.conn.Close()
if err != nil {
return err
} else if errD != nil {
return errD
}
return errW
}
// scanError returns the error from the scanner if non-nil,
// io.ErrUnexpectedEOF otherwise.
func (c *Client) scanErr() error {
if err := c.scanner.Err(); err != nil {
return err
}
return io.ErrUnexpectedEOF
}