sample-go.go

package main

import (
  "os"
  "fmt"
  "time"
  "errors"
  "math/rand"
  ioutil "io/ioutil"
  http "net/http"
)

// HealthBadCount suck it
var HealthBadCount = 0

func statusServer() {
    http.HandleFunc("/ping", pingHandle)
    http.HandleFunc("/health", healthHandle)
    http.HandleFunc("/healthBad", healthBadHandle)
    http.HandleFunc("/pvDataReturn", pvDataReturn)
    http.HandleFunc("/pvDataSet", pvDataSet)
    http.HandleFunc("/apiTest", downwardAPITester)

    //  create server that doesn't leave things open forever
    s := &http.Server{
            Addr:           ":8080",
            ReadTimeout:    10 * time.Second,
            WriteTimeout:   10 * time.Second,
        }
    s.ListenAndServe()
}

func pingHandle(w http.ResponseWriter, r *http.Request){
    if r.Method == "GET" {
        fmt.Fprintf(w, "PONG\n")
    }
}

func healthHandle(w http.ResponseWriter, r *http.Request){
    if r.Method == "GET" {
        fmt.Fprintf(w, "health\n")
    }
}

func pvDataReturn(w http.ResponseWriter, r *http.Request){
    if r.Method == "GET" {
        pvData, err := ioutil.ReadFile("/mnt/cephfs/pvData")
        if err != nil {
            fmt.Fprintf(w, "PV not present\n")
        } else {
            fmt.Fprintf(w, string(pvData[:]) + "\n")
        }
    }
}

func pvDataSet(w http.ResponseWriter, r *http.Request){
    if r.Method == "PUT" {
        bytes := make([]byte, 100)
        _, err := r.Body.Read(bytes)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)            
            fmt.Fprintf(w, "Failed to read PUT data\n")
        }
        
        err = ioutil.WriteFile("/mnt/cephfs/pvData", bytes, os.ModePerm)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            fmt.Fprintf(w, "PV not present\n")
        } else {
            fmt.Fprintf(w, "Data saved")
        }
    }
}

var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")

func randSeq(n int) string {
    b := make([]rune, n)
    for i := range b {
        b[i] = letters[rand.Intn(len(letters))]
    }
    return string(b)
}

func downwardAPITester(w http.ResponseWriter, r *http.Request){
    bytes := make([]byte, 100)
    _, err := r.Body.Read(bytes)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)            
        fmt.Fprintf(w, "Failed to read PUT data\n")
    }
        
    err = ioutil.WriteFile("/var/log/containers/sample-go/" + randSeq(10), bytes, os.ModePerm)
    if err != nil {
        w.WriteHeader(http.StatusInternalServerError)
        fmt.Fprintf(w, "PV not present\n")
    } else {
        fmt.Fprintf(w, "Data saved")
    }
}

func healthBadHandle(w http.ResponseWriter, r *http.Request){
    if r.Method == "GET" {
        HealthBadCount++
        if HealthBadCount > 15 {
            w.WriteHeader(http.StatusInternalServerError)
        }
        fmt.Fprintf(w, "health count %d next\n", HealthBadCount)
    }
}

func namedOutput(filehandle *os.File) {
    counter := 0
    for {
        time.Sleep(time.Second)
        fmt.Fprintf(filehandle, "oh look!  a message on %s! id:  %d\n", filehandle.Name(), counter)
        counter++
    }
}

func forTesting(number, multiplier int) (calculated int, err error) {
    if number * multiplier > 50 {
        err = errors.New("Number too high")
    } else {
        calculated = number * multiplier
    }

    return
}

func main() {
    custom, err := os.Create("/lorst")
    if err != nil {
        fmt.Fprintln(os.Stderr, "Failed to open custom log handle")
    } else {
        go namedOutput(custom)
    }
    go namedOutput(os.Stderr)
    go namedOutput(os.Stdout)
    statusServer()
}