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DazWilkin/Dockerfile

Last active August 16, 2018 17:00
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Kubernetes Engine from sratch #2
Raw
Dockerfile
FROM golang:1.10-stretch as build
WORKDIR /go/src/app
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o /go/bin/app/main .
FROM scratch
LABEL maintainer="Your Name <[email protected]"
COPY --from=build /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
COPY --from=build /go/bin/app/ /
ARG VERSION=0
ENV VERSION=${VERSION}
EXPOSE 8080
ENTRYPOINT ["/main"]
Raw
main.go
package main
import (
"fmt"
"html/template"
"log"
"net"
"net/http"
"os"
"strings"
)
const (
html = `<!doctype html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name=viewport content="width=device-width, initial-scale=1">
<title>Knowing Node</title>
<style>
body {
font-family: Helvetica;
}
table,tr {
border: 2px solid #f5f5f5;
border-collapse: collapse;
}
tr:hover {
background-color: #f5f5f5;
}
</style>
</head>
<body border="1">
<table>
{{- range . }}
<tr>
<td><a href="{{.}}">{{.}}</a></td>
</tr>
{{- end }}
</table>
</body>
</html>`
)
func main() {
http.HandleFunc("/", defaultHandler)
http.HandleFunc("/_ah/health", healthzHandler)
http.HandleFunc("/backend", backendHandler)
http.HandleFunc("/healthz", healthzHandler)
http.HandleFunc("/hostz", hostzHandler)
http.HandleFunc("/requestz", requestzHandler)
http.HandleFunc("/varz", varzHandler)
http.HandleFunc("/version", versionHandler)
http.ListenAndServe(":8080", nil)
}
func defaultHandler(w http.ResponseWriter, r *http.Request) {
tpl := template.Must(template.New("out").Parse(html))
urls := []string{
"/",
"/_ah/health",
"/backend",
"/healthz",
"/hostz",
"/requestz",
"/varz",
"/version"}
tpl.Execute(w, urls)
}
func backendHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "[node] %v (%v)\n", os.Getenv("NODE_NAME"), os.Getenv("NODE_IP"))
fmt.Fprintf(w, "[pod] %v (%v)\n", os.Getenv("POD_NAME"), os.Getenv("POD_IP"))
}
func healthzHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, "OK")
}
func hostzHandler(w http.ResponseWriter, r *http.Request) {
cname, addrs, err := net.LookupSRV("http", "tcp", os.Getenv("SERVICE_NAME"))
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
log.Printf("CNAME: %v\n", cname)
for _, addr := range addrs {
url := fmt.Sprintf("http://%v:%v/backend",
strings.TrimSuffix(addr.Target, "."),
addr.Port)
resp, err := http.Get(url)
if err != nil {
log.Printf("%v: %v", url, err)
}
defer resp.Body.Close()
fmt.Fprintf(w, "%v: %v\n", url, resp.StatusCode)
}
}
func requestzHandler(w http.ResponseWriter, r *http.Request) {
urls := []string{
"https://www.cnn.com",
"https://www.cnn.com/robots.txt",
"http://www.bbc.com/robots.txt"}
for _, url := range urls {
resp, err := http.Get(url)
if err != nil {
}
defer resp.Body.Close()
fmt.Fprintf(w, "%v: %v\n", url, resp.StatusCode)
}
}
func varzHandler(w http.ResponseWriter, r *http.Request) {
for _, e := range os.Environ() {
fmt.Fprintf(w, "%v\n", e)
}
}
func versionHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, os.Getenv("VERSION"))
}
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