/
main.go
126 lines (102 loc) · 2.83 KB
/
main.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
package main
import (
"context"
"errors"
"flag"
"fmt"
"log"
"net/http"
"os"
"os/signal"
"strings"
"sync"
"syscall"
"time"
)
var (
listenFlag string
responseStatusCodeFlag int
responseBodyFlag string
logFullHeader bool
VersionFlag bool
Name string
Version string
GitCommit string
)
const (
SEP = ","
)
func init() {
flag.StringVar(&listenFlag, "listen", ":8081,", "Ports on an HTTP echo server is going to be listening (Comma separated values)")
flag.IntVar(&responseStatusCodeFlag, "response_status", 200, "Response status code to be sent")
flag.StringVar(&responseBodyFlag, "response_body", "Hello, World!", "Response body to be sent")
flag.BoolVar(&logFullHeader, "log_headers", false, "Log full header")
flag.BoolVar(&VersionFlag, "version", false, "Display version information at start")
}
func listenAndServe(addr string, handler http.Handler, closeCtx context.Context, wg *sync.WaitGroup) {
defer wg.Done()
server := http.Server{
Addr: addr,
Handler: handler,
}
go func() {
log.Printf("[INFO] Server listening on address '%s'", server.Addr)
if err := server.ListenAndServe(); err != http.ErrServerClosed {
log.Printf("[ERROR] Error starting server. Err: %s", err)
os.Exit(1)
}
}()
<-closeCtx.Done()
timeoutCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
err := server.Shutdown(timeoutCtx)
if err != nil {
log.Printf("[ERROR] Error shutting down server. Err: %s", err)
} else {
log.Printf("[INFO] Server '%s' gracefully shutdown", server.Addr)
}
}
func parseListenAddresses(listen string) ([]string, error) {
var addressesList []string
for _, addr := range strings.Split(listen, SEP) {
trimmedAddr := strings.TrimSpace(addr)
if trimmedAddr == "" {
continue
}
addressesList = append(addressesList, trimmedAddr)
}
if len(addressesList) == 0 {
return nil, errors.New("[ERROR] Invalid list of addresses provided")
}
return addressesList, nil
}
func main() {
// Parse and validate flags
flag.Parse()
if len(flag.Args()) > 0 {
log.Fatalln("[ERROR] Invalid number of flags provided, see `-help` flag")
}
// Return version details if flag is set
if VersionFlag {
fmt.Printf("%s - version: %s (SHA: %s)", Name, Version, GitCommit)
os.Exit(0)
}
mux := http.NewServeMux()
mux.HandleFunc("/", appendHeaders(logRequest(httpEcho)))
mux.HandleFunc("/health", appendHeaders(httpHealth))
addressesList, err := parseListenAddresses(listenFlag)
if err != nil {
log.Fatalf("%s", err)
}
wg := &sync.WaitGroup{}
closeCtx, closeServer := context.WithCancel(context.Background())
for _, addr := range addressesList {
go listenAndServe(addr, mux, closeCtx, wg)
wg.Add(1)
}
exitChan := make(chan os.Signal, 0)
signal.Notify(exitChan, os.Interrupt, syscall.SIGTERM)
<-exitChan
closeServer()
wg.Wait()
}