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package main
import (
"bufio"
"fmt"
"io"
"log"
"net/http"
"os"
"os/exec"
"path/filepath"
"regexp"
"strconv"
"strings"
"time"
)
type Filter struct {
keep bool
pattern *regexp.Regexp
}
const userAgent = "metra/0.1"
var filters []Filter
func responseHandler(body io.ReadCloser, timestamp int64) {
scanner := bufio.NewScanner(body)
defer body.Close()
for scanner.Scan() {
line := scanner.Text()
if line == "" || strings.HasPrefix(line, "#") {
continue
}
// XXX detect if a timestamp is there and forward it?
// XXX normalize label order
// XXX normalize spacing
// XXX add labels from config file, targets?
sp := strings.LastIndexByte(line, ' ')
if sp > 0 {
name := line[:sp]
value := line[sp+1:]
keep := true
for _, filter := range filters {
if filter.pattern.MatchString(name) {
keep = filter.keep
}
}
if keep {
fmt.Printf("%s %s %d\n", name, value, timestamp)
}
}
}
}
func sleepInterval(interval int) time.Time {
now := time.Now().UTC()
next := now.Add(time.Duration(interval) * time.Second).
Truncate(time.Duration(interval) * time.Second)
time.Sleep(next.Sub(now))
return next
}
func httpPoll(url string, interval int) {
client := http.Client{
Timeout: 5 * time.Second,
}
for {
now := sleepInterval(interval)
fmt.Printf("now: %v\n", time.Now().UTC())
req, _ := http.NewRequest("GET", url, nil)
req.Header.Set("User-Agent", userAgent)
res, err := client.Get(url)
if err != nil {
fmt.Fprintf(os.Stderr, "http error: %s\n", err)
continue
}
if res.StatusCode != 200 {
fmt.Fprintf(os.Stderr, "http status: %d\n", res.StatusCode)
continue
}
responseHandler(res.Body, now.UnixMilli())
}
}
func filePoll(path string, interval int) {
for {
now := sleepInterval(interval)
fmt.Printf("now: %v\n", time.Now().UTC())
file, err := os.Open(path)
if err != nil {
log.Print(err)
// handle the error and return
continue
}
fi, err := file.Stat()
switch mode := fi.Mode(); {
case mode.IsRegular():
responseHandler(file, now.UnixMilli())
case mode.IsDir():
file.Close()
files, err := filepath.Glob(path + "/*.prom")
if err != nil {
log.Fatal(err)
}
for _, filename := range files {
file, err := os.Open(filename)
if err != nil {
log.Print(err)
// handle the error and return
continue
}
responseHandler(file, now.UnixMilli())
}
}
}
}
func pipePoll(command string, interval int) {
for {
now := sleepInterval(interval)
fmt.Printf("now sh: %v\n", time.Now().UTC())
var cmd *exec.Cmd
if strings.Index(command, " ") != -1 {
cmd = exec.Command("/bin/sh", "-c", command)
} else {
cmd = exec.Command(command)
}
stdout, err := cmd.StdoutPipe()
if err != nil {
log.Print(err)
}
cmd.Start()
responseHandler(stdout, now.UnixMilli())
err = cmd.Wait()
if exiterr, ok := err.(*exec.ExitError); ok {
log.Printf("command exited with status %d\n",
exiterr.ExitCode())
}
}
}
func main() {
if len(os.Args) != 2 {
fmt.Fprintf(os.Stderr, "usage: %s configfile\n", os.Args[0])
os.Exit(-1)
}
file, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer file.Close()
interval := 60
interval = 1
scanner := bufio.NewScanner(file)
for scanner.Scan() {
line := scanner.Text()
if line == "" || strings.HasPrefix(line, "#") {
continue
} else if match, _ := regexp.MatchString(`^https?:`, line); match {
go httpPoll(line, interval)
} else if match, _ := regexp.MatchString(`^file://`, line); match {
go filePoll(line[7:], interval)
} else if match, _ := regexp.MatchString(`^/`, line); match {
go filePoll(line, interval)
} else if strings.HasPrefix(line, "-") || strings.HasPrefix(line, "+") {
pattern, err := regexp.Compile(strings.TrimSpace(line[1:]))
if err != nil {
log.Fatal(err)
}
filters = append(filters, Filter{line[0] == '+', pattern})
} else if strings.HasPrefix(line, "$") {
go pipePoll(strings.TrimSpace(line[1:]), interval)
} else if strings.HasPrefix(line, "@") {
i, err := strconv.Atoi(strings.TrimSpace(line[1:]))
if err != nil {
log.Fatal(err)
}
interval = i
} else {
log.Fatalf("invalid config line: %s\n", line)
}
}
if err := scanner.Err(); err != nil {
log.Fatal(err)
}
fmt.Println("hi")
select {}
}
|
