/
falcosidekick.go
129 lines (109 loc) · 3.69 KB
/
falcosidekick.go
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// Copyright Dwi Siswanto and/or licensed to Dwi Siswanto under one
// or more contributor license agreements. Licensed under the Elastic License 2.0;
// you may not use this file except in compliance with the Elastic License 2.0.
// See the LICENSE-ELASTIC file in the project root for more information.
package teler
import (
"bytes"
"time"
"encoding/json"
"net/http"
"github.com/daniel-hutao/spinlock"
"github.com/sourcegraph/conc/pool"
"go.uber.org/zap/zapcore"
"golang.org/x/exp/slices"
)
// falcoEvent represents a Falco event structure.
// It is used for marshaling Falco events to JSON format.
type falcoEvent struct {
Output string `json:"output"`
Priority string `json:"priority"`
Rule string `json:"rule"`
Time string `json:"time"`
OutputFields struct {
Caller string `json:"teler.caller"`
ID string `json:"teler.id"`
Threat string `json:"teler.threat"`
RequestBody string `json:"request.body"`
RequestHeaders string `json:"request.headers"`
RequestIPAddr string `json:"request.ip_addr"`
RequestMethod string `json:"request.method"`
RequestPath string `json:"request.path"`
} `json:"output_fields"`
}
// falcoSidekick represents a data structure for managing
// a collection of Falco events and a SpinLock for concurrent
// access control.
type falcoSidekick struct {
events []*falcoEvent
sl spinlock.SpinLock
}
// checkFalcoEvents periodically checks for pending Falco events and
// sends them to a FalcoSidekick instance.
//
// If the FalcoSidekick URL is configured. It runs as a background goroutine.
func (t *Teler) checkFalcoEvents() {
// If the FalcoSidekick URL is not configured, do nothing.
if t.opt.FalcoSidekickURL == "" {
return
}
// Initialize ticker
ticker := time.NewTicker(time.Second * 5)
defer ticker.Stop()
// Check for pending Falco events every 5 seconds.
for range ticker.C {
// Lock the FalcoSidekick event
t.falcoSidekick.sl.Lock()
// Get the count of pending Falco events.
c := len(t.falcoSidekick.events)
if c > 0 {
// Send pending Falco events to FalcoSidekick.
t.sendFalcoEvents()
}
// Unlock the FalcoSidekick event
t.falcoSidekick.sl.Unlock()
}
}
// sendFalcoEvents sends pending Falco events to a FalcoSidekick instance.
// It uses a goroutine pool to parallelize the sending of events.
func (t *Teler) sendFalcoEvents() {
// Lock the FalcoSidekick event slice to prevent concurrent access.
t.falcoSidekick.sl.Lock()
defer t.falcoSidekick.sl.Unlock()
// Get the number of pending Falco events.
i := len(t.falcoSidekick.events)
// Initialize worker number
var w int
// Define worker number logic
w = i / 2
if w == 0 {
w = 1
}
// Create a goroutine pool with a maximum number of goroutines (workers)
// equal to half the number of pending events.
p := pool.New().WithMaxGoroutines(w)
// Iterate over the pending Falco events.
for _, event := range t.falcoSidekick.events {
e := event
p.Go(func() {
// Marshal the Falco event to JSON format.
payload, err := json.Marshal(e)
if err != nil {
// Handle JSON marshaling error by logging an error message.
t.error(zapcore.ErrorLevel, err.Error())
}
// Send a POST request to the FalcoSidekick instance with the JSON payload.
resp, err := http.Post(t.opt.FalcoSidekickURL, "application/json", bytes.NewBuffer(payload))
if err != nil {
// Handle HTTP POST request error by logging an error message.
t.error(zapcore.ErrorLevel, err.Error())
} else {
defer resp.Body.Close()
}
})
}
// Wait for all goroutines in the pool to complete.
p.Wait()
// Remove sent Falco events from the pending events slice.
t.falcoSidekick.events = slices.Delete(t.falcoSidekick.events, 0, i)
}