forked from pebbe/zmq4
-
Notifications
You must be signed in to change notification settings - Fork 0
/
flclient1.go
77 lines (68 loc) · 1.82 KB
/
flclient1.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
//
// Freelance client - Model 1.
// Uses REQ socket to query one or more services
//
package main
import (
zmq "github.com/pebbe/zmq4"
"errors"
"fmt"
"os"
"time"
)
const (
REQUEST_TIMEOUT = 1000 * time.Millisecond
MAX_RETRIES = 3 // Before we abandon
)
func try_request(endpoint string, request []string) (reply []string, err error) {
fmt.Printf("I: trying echo service at %s...\n", endpoint)
client, _ := zmq.NewSocket(zmq.REQ)
client.Connect(endpoint)
// Send request, wait safely for reply
client.SendMessage(request)
poller := zmq.NewPoller()
poller.Add(client, zmq.POLLIN)
polled, err := poller.Poll(REQUEST_TIMEOUT)
reply = []string{}
if len(polled) == 1 {
reply, err = client.RecvMessage(0)
} else {
err = errors.New("Time out")
}
return
}
// The client uses a Lazy Pirate strategy if it only has one server to talk
// to. If it has 2 or more servers to talk to, it will try each server just
// once:
func main() {
request := []string{"Hello world"}
reply := []string{}
var err error
endpoints := len(os.Args) - 1
if endpoints == 0 {
fmt.Printf("I: syntax: %s <endpoint> ...\n", os.Args[0])
} else if endpoints == 1 {
// For one endpoint, we retry N times
for retries := 0; retries < MAX_RETRIES; retries++ {
endpoint := os.Args[1]
reply, err = try_request(endpoint, request)
if err == nil {
break // Successful
}
fmt.Printf("W: no response from %s, retrying...\n", endpoint)
}
} else {
// For multiple endpoints, try each at most once
for endpoint_nbr := 0; endpoint_nbr < endpoints; endpoint_nbr++ {
endpoint := os.Args[endpoint_nbr+1]
reply, err = try_request(endpoint, request)
if err == nil {
break // Successful
}
fmt.Println("W: no response from", endpoint)
}
}
if len(reply) > 0 {
fmt.Printf("Service is running OK: %q\n", reply)
}
}