expvarmon/utils.go

150 lines
3.5 KiB
Go

package main
import (
"errors"
"fmt"
"net/url"
"path/filepath"
"strings"
"github.com/bsiegert/ranges"
)
var ErrParsePorts = fmt.Errorf("cannot parse ports argument")
// ParseVars returns parsed and validated slice of strings with
// variables names that will be used for monitoring.
func ParseVars(vars string) ([]VarName, error) {
if vars == "" {
return nil, errors.New("no vars specified")
}
ss := strings.FieldsFunc(vars, func(r rune) bool { return r == ',' })
var ret []VarName
for _, s := range ss {
ret = append(ret, VarName(s))
}
return ret, nil
}
// BaseCommand returns cleaned command name from Cmdline array.
//
// I.e. "./some.service/binary.name -arg 1 -arg" will be "binary.name".
func BaseCommand(cmdline []string) string {
if len(cmdline) == 0 {
return ""
}
return filepath.Base(cmdline[0])
}
// flattenURLs returns URLs for the given addr and set of ports.
//
// Note, rawurl shouldn't contain port, as port will be appended.
func flattenURLs(rawurl string, ports []string) ([]url.URL, error) {
var urls []url.URL
// Add http by default
if !strings.HasPrefix(rawurl, "http") {
rawurl = fmt.Sprintf("http://%s", rawurl)
}
// Make URL from rawurl
baseURL, err := url.Parse(rawurl)
if err != nil {
return nil, err
}
if baseURL.Path == "" {
baseURL.Path = DefaultEndpoint
}
// Create new URL for each port
for _, port := range ports {
u := *baseURL
u.Host = fmt.Sprintf("%s:%s", u.Host, port)
urls = append(urls, u)
}
return urls, nil
}
// ParsePorts parses and flattens comma-separated ports/urls into URLs slice
func ParsePorts(s string) ([]url.URL, error) {
var urls []url.URL
fields := strings.FieldsFunc(s, func(r rune) bool { return r == ',' })
for _, field := range fields {
rawurl, portsRange := extractURLAndPorts(field)
ports, err := parseRange(portsRange)
if err != nil {
return nil, ErrParsePorts
}
purls, err := flattenURLs(rawurl, ports)
if err != nil {
return nil, ErrParsePorts
}
urls = append(urls, purls...)
}
return urls, nil
}
// extractUrlAndPorts attempts to split url and extract raw url
// for the single port and range of ports to parse.
//
// i.e. "http://name:1234-1236/_endpoint" would return "http://name/_endpoint" and
// "1234-1236"
func extractURLAndPorts(s string) (string, string) {
var rawurl, ports string
parts := strings.Split(s, ":")
switch len(parts) {
case 1:
// "1234-234"
rawurl = "http://localhost"
ports = parts[0]
case 2:
// "localhost:1234"
rawurl, ports = parts[0], parts[1]
default:
// "https://user:pass@remote.name:1234" or "http://name:1234-1236/_endpoint"
// construct endpoint from the first part of URI, before ports appera
rawurl = strings.Join(parts[:len(parts)-1], ":")
// get either "1234-1235" or "1234-1235/_endpoint"
lastPart := parts[len(parts)-1]
// try to find endpoint and attach it to rawurl
fields := strings.SplitN(lastPart, "/", 2)
ports = fields[0]
if len(fields) > 1 {
rawurl = fmt.Sprintf("%s/%s", rawurl, fields[1])
}
}
return rawurl, ports
}
// parseRange flattens port ranges, such as "1234-1240,1333"
func parseRange(s string) ([]string, error) {
portsInt, err := ranges.Parse(s)
if err != nil {
return nil, err
}
var ports []string
for _, port := range portsInt {
ports = append(ports, fmt.Sprintf("%d", port))
}
return ports, nil
}
// NewURL returns net.URL for the given port, with expvarmon defaults set.
func NewURL(port string) url.URL {
return url.URL{
Scheme: "http",
Host: fmt.Sprintf("localhost:%s", port),
Path: "/debug/vars",
}
}