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// SPDX-License-Identifier: GPL-3.0-or-later
package netlisteners
import (
"bufio"
"bytes"
"context"
"errors"
"fmt"
"log/slog"
"os"
"os/exec"
"path/filepath"
"strings"
"time"
"github.com/netdata/netdata/go/go.d.plugin/agent/discovery/sd/model"
"github.com/netdata/netdata/go/go.d.plugin/agent/executable"
"github.com/netdata/netdata/go/go.d.plugin/logger"
"github.com/ilyam8/hashstructure"
)
var (
shortName = "net_listeners"
fullName = fmt.Sprintf("sd:%s", shortName)
)
func NewDiscoverer(cfg Config) (*Discoverer, error) {
tags, err := model.ParseTags(cfg.Tags)
if err != nil {
return nil, fmt.Errorf("parse tags: %v", err)
}
dir := os.Getenv("NETDATA_PLUGINS_DIR")
if dir == "" {
dir = executable.Directory
}
if dir == "" {
dir, _ = os.Getwd()
}
d := &Discoverer{
Logger: logger.New().With(
slog.String("component", "service discovery"),
slog.String("discoverer", shortName),
),
cfgSource: cfg.Source,
interval: time.Second * 60,
ll: &localListenersExec{
binPath: filepath.Join(dir, "local-listeners"),
timeout: time.Second * 5,
},
}
d.Tags().Merge(tags)
return d, nil
}
type Config struct {
Source string `yaml:"-"`
Tags string `yaml:"tags"`
}
type (
Discoverer struct {
*logger.Logger
model.Base
cfgSource string
interval time.Duration
ll localListeners
}
localListeners interface {
discover(ctx context.Context) ([]byte, error)
}
)
func (d *Discoverer) String() string {
return fullName
}
func (d *Discoverer) Discover(ctx context.Context, in chan<- []model.TargetGroup) {
if err := d.discoverLocalListeners(ctx, in); err != nil {
d.Error(err)
return
}
//tk := time.NewTicker(d.interval)
//defer tk.Stop()
//
//for {
// select {
// case <-ctx.Done():
// return
// case <-tk.C:
// if err := d.discoverLocalListeners(ctx, in); err != nil {
// d.Error(err)
// return
// }
// }
//}
}
func (d *Discoverer) discoverLocalListeners(ctx context.Context, in chan<- []model.TargetGroup) error {
bs, err := d.ll.discover(ctx)
if err != nil {
if errors.Is(err, context.Canceled) {
return nil
}
return err
}
tggs, err := d.parseLocalListeners(bs)
if err != nil {
return err
}
select {
case <-ctx.Done():
case in <- tggs:
}
return nil
}
func (d *Discoverer) parseLocalListeners(bs []byte) ([]model.TargetGroup, error) {
var tgts []model.Target
sc := bufio.NewScanner(bytes.NewReader(bs))
for sc.Scan() {
text := strings.TrimSpace(sc.Text())
if text == "" {
continue
}
// Protocol|Address|Port|Cmdline
parts := strings.SplitN(text, "|", 4)
if len(parts) != 4 {
return nil, fmt.Errorf("unexpected data: '%s'", text)
}
tgt := target{
Protocol: parts[0],
Address: parts[1],
Port: parts[2],
Comm: extractComm(parts[3]),
Cmdline: parts[3],
}
hash, err := calcHash(tgt)
if err != nil {
continue
}
tgt.hash = hash
tgt.Tags().Merge(d.Tags())
tgts = append(tgts, &tgt)
}
tgg := &targetGroup{
provider: fullName,
source: fmt.Sprintf("discoverer=%s,host=localhost", shortName),
targets: tgts,
}
if d.cfgSource != "" {
tgg.source += fmt.Sprintf(",%s", d.cfgSource)
}
return []model.TargetGroup{tgg}, nil
}
type localListenersExec struct {
binPath string
timeout time.Duration
}
func (e *localListenersExec) discover(ctx context.Context) ([]byte, error) {
execCtx, cancel := context.WithTimeout(ctx, e.timeout)
defer cancel()
// TCPv4 and UPDv4 sockets in LISTEN state
// https://github.com/netdata/netdata/blob/master/src/collectors/plugins.d/local_listeners.c
args := []string{
"no-udp6",
"no-tcp6",
"no-local",
"no-inbound",
"no-outbound",
"no-namespaces",
}
cmd := exec.CommandContext(execCtx, e.binPath, args...)
bs, err := cmd.Output()
if err != nil {
return nil, fmt.Errorf("error on executing '%s': %v", cmd, err)
}
return bs, nil
}
func extractComm(cmdLine string) string {
i := strings.IndexByte(cmdLine, ' ')
if i <= 0 {
return cmdLine
}
_, comm := filepath.Split(cmdLine[:i])
return comm
}
func calcHash(obj any) (uint64, error) {
return hashstructure.Hash(obj, nil)
}
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