/
main.go
199 lines (167 loc) · 4.32 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
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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
package main
import (
"context"
"fmt"
"log"
"net/http"
"os"
"os/signal"
"strconv"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promhttp"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
)
func main() {
var contextTimeout time.Duration
if v, exists := os.LookupEnv("CONTEXT_TIMEOUT"); exists {
parsed, err := time.ParseDuration(v)
if err != nil {
log.Fatalf("bad env var: %s", err)
}
contextTimeout = parsed
}
tickInterval := time.Millisecond * 100
if v, exists := os.LookupEnv("TICK_INTERVAL"); exists {
parsed, err := time.ParseDuration(v)
if err != nil {
log.Fatalf("bad env var: %s", err)
}
tickInterval = parsed
}
namespace := "demo"
if v, exists := os.LookupEnv("NAMESPACE"); exists {
namespace = v
}
targetNamespace := "demo"
if v, exists := os.LookupEnv("TARGET_NAMESPACE"); exists {
targetNamespace = v
}
pod := ""
if v, exists := os.LookupEnv("POD_NAME"); exists {
pod = v
}
showErrorsOnly := true
if v, exists := os.LookupEnv("SHOW_ERRORS_ONLY"); exists {
if parsed, err := strconv.ParseBool(v); err == nil {
showErrorsOnly = parsed
}
}
log.Printf("namespace: %s, pod: %s, target namespace: %s, tick interval: %s, show errors only: %t",
namespace, pod, targetNamespace, tickInterval, showErrorsOnly)
var (
dataChan = make(chan string)
errChan = make(chan error)
exit = make(chan os.Signal, 1)
mainCtx, mainCancel = context.WithCancel(context.Background())
listOpts = metav1.ListOptions{}
)
signal.Notify(exit, os.Interrupt, os.Kill)
clientset, err := clientSet()
if err != nil {
log.Fatalf("can't set up K8s clientset: %s", err)
}
requestCounter, err := registerCounter()
if err != nil {
log.Fatalf("fail to register Prometheus counter: %s", err)
}
server, err := startHTTPServer()
defer func() {
ctx, cancel := context.WithTimeout(mainCtx, time.Second*5)
defer cancel()
server.Shutdown(ctx)
}()
go func() {
for {
select {
case <-mainCtx.Done():
msg := "exiting goroutine"
if err := mainCtx.Err(); err != nil {
msg += fmt.Sprintf(": %s", err)
}
log.Print(msg)
break
case <-time.Tick(tickInterval):
go func() {
ctx, cancel := context.WithCancel(mainCtx)
if contextTimeout > 0 {
ctx, cancel = context.WithTimeout(mainCtx, contextTimeout)
}
defer cancel()
requestLabels := prometheus.Labels{
"namespace": namespace,
"pod": pod,
"target_namespace": targetNamespace,
}
requestCounter.With(requestLabels).Inc()
pods, err := clientset.CoreV1().Pods(targetNamespace).List(ctx, listOpts)
if err != nil {
errChan <- fmt.Errorf("error while listing pods: %s", err)
return
}
if showErrorsOnly {
return
}
if len(pods.Items) == 0 {
dataChan <- fmt.Sprintf("no pods found in namespace %s", targetNamespace)
return
}
foundPods := []string{}
for _, pod := range pods.Items {
foundPods = append(foundPods, pod.Name)
}
dataChan <- fmt.Sprintf("%s", Result{Namespace: targetNamespace, Pods: foundPods})
}()
}
}
}()
for {
select {
case err := <-errChan:
log.Println(err)
case data := <-dataChan:
log.Println(data)
case <-exit:
mainCancel()
break
}
}
}
func registerCounter() (*prometheus.CounterVec, error) {
counter := prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "demo_http_requests_total",
Help: "A counter for requests issued by the demo controllers.",
},
[]string{"namespace", "target_namespace", "pod"},
)
if err := prometheus.Register(counter); err != nil {
return nil, err
}
return counter, nil
}
func clientSet() (*kubernetes.Clientset, error) {
config, err := rest.InClusterConfig()
if err != nil {
return nil, err
}
return kubernetes.NewForConfig(config)
}
func startHTTPServer() (*http.Server, error) {
server := &http.Server{Addr: ":8080"}
go func() {
mux := http.NewServeMux()
mux.Handle("/metrics", promhttp.Handler())
server.Handler = mux
if err := server.ListenAndServe(); err != nil {
log.Println(err)
}
}()
return server, nil
}
type Result struct {
Namespace string `json:"namespace"`
Pods []string `json:"pods"`
}