122 lines
3.2 KiB
Go
122 lines
3.2 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// A tiny web server for viewing the environment kubernetes creates for your
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// containers. It exposes the filesystem and environment variables via http
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// server.
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package main
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import (
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"flag"
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"fmt"
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"log"
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"net"
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"net/http"
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"os"
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"github.com/davecgh/go-spew/spew"
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)
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var (
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port = flag.Int("port", 8080, "Port number to serve at.")
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)
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func main() {
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flag.Parse()
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hostname, err := os.Hostname()
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if err != nil {
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log.Fatalf("Error getting hostname: %v", err)
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}
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links := []struct {
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link, desc string
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}{
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{"/fs/", "Complete file system as seen by this container."},
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{"/vars/", "Environment variables as seen by this container."},
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{"/hostname/", "Hostname as seen by this container."},
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{"/dns?q=google.com", "Explore DNS records seen by this container."},
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{"/quit", "Cause this container to exit."},
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}
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http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, "<b> Kubernetes environment explorer </b><br/><br/>")
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for _, v := range links {
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fmt.Fprintf(w, `<a href="%v">%v: %v</a><br/>`, v.link, v.link, v.desc)
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}
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})
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http.Handle("/fs/", http.StripPrefix("/fs/", http.FileServer(http.Dir("/"))))
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http.HandleFunc("/vars/", func(w http.ResponseWriter, r *http.Request) {
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for _, v := range os.Environ() {
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fmt.Fprintf(w, "%v\n", v)
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}
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})
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http.HandleFunc("/hostname/", func(w http.ResponseWriter, r *http.Request) {
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fmt.Fprintf(w, hostname)
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})
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http.HandleFunc("/quit", func(w http.ResponseWriter, r *http.Request) {
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os.Exit(0)
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})
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http.HandleFunc("/dns", dns)
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go log.Fatal(http.ListenAndServe(fmt.Sprintf("0.0.0.0:%d", *port), nil))
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select {}
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}
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func dns(w http.ResponseWriter, r *http.Request) {
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q := r.URL.Query().Get("q")
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// Note that the below is NOT safe from input attacks, but that's OK
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// because this is just for debugging.
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fmt.Fprintf(w, `<html><body>
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<form action="/dns">
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<input name="q" type="text" value="%v"></input>
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<button type="submit">Lookup</button>
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</form>
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<br/><br/><pre>`, q)
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{
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res, err := net.LookupNS(q)
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spew.Fprintf(w, "LookupNS(%v):\nResult: %#v\nError: %v\n\n", q, res, err)
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}
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{
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res, err := net.LookupTXT(q)
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spew.Fprintf(w, "LookupTXT(%v):\nResult: %#v\nError: %v\n\n", q, res, err)
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}
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{
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cname, res, err := net.LookupSRV("", "", q)
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spew.Fprintf(w, `LookupSRV("", "", %v):
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cname: %v
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Result: %#v
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Error: %v
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`, q, cname, res, err)
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}
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{
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res, err := net.LookupHost(q)
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spew.Fprintf(w, "LookupHost(%v):\nResult: %#v\nError: %v\n\n", q, res, err)
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}
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{
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res, err := net.LookupIP(q)
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spew.Fprintf(w, "LookupIP(%v):\nResult: %#v\nError: %v\n\n", q, res, err)
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}
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{
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res, err := net.LookupMX(q)
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spew.Fprintf(w, "LookupMX(%v):\nResult: %#v\nError: %v\n\n", q, res, err)
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}
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fmt.Fprintf(w, `</pre>
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</body>
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</html>`)
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}
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