feat(autotune): add Bayesian hyperparameter optimization

Gaussian process-based optimizer for both DDoS and scanner models.
Samples hyperparameter space (k, threshold, window_secs, min_events,
heuristic thresholds) and optimizes F-beta score with expected
improvement acquisition. Logs each trial to optional JSONL file.

Signed-off-by: Sienna Meridian Satterwhite <sienna@sunbeam.pt>
This commit is contained in:
2026-03-10 23:38:21 +00:00
parent 1f4366566d
commit 565ea4cde4
6 changed files with 916 additions and 0 deletions

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src/autotune/ddos.rs Normal file
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use crate::autotune::optimizer::BayesianOptimizer;
use crate::autotune::params::{ParamDef, ParamSpace, ParamType};
use crate::ddos::replay::{ReplayArgs, replay_and_evaluate};
use crate::ddos::train::{HeuristicThresholds, train_model_from_states, parse_logs};
use anyhow::{Context, Result};
use std::io::Write;
use std::time::Instant;
pub struct AutotuneDdosArgs {
pub input: String,
pub output: String,
pub trials: usize,
pub beta: f64,
pub trial_log: Option<String>,
}
fn ddos_param_space() -> ParamSpace {
ParamSpace::new(vec![
ParamDef { name: "k".into(), param_type: ParamType::Integer { min: 1, max: 20 } },
ParamDef { name: "threshold".into(), param_type: ParamType::Continuous { min: 0.1, max: 0.95 } },
ParamDef { name: "window_secs".into(), param_type: ParamType::Integer { min: 10, max: 300 } },
ParamDef { name: "min_events".into(), param_type: ParamType::Integer { min: 3, max: 50 } },
ParamDef { name: "request_rate".into(), param_type: ParamType::Continuous { min: 1.0, max: 100.0 } },
ParamDef { name: "path_repetition".into(), param_type: ParamType::Continuous { min: 0.3, max: 0.99 } },
ParamDef { name: "error_rate".into(), param_type: ParamType::Continuous { min: 0.2, max: 0.95 } },
ParamDef { name: "suspicious_path_ratio".into(), param_type: ParamType::Continuous { min: 0.05, max: 0.8 } },
ParamDef { name: "no_cookies_threshold".into(), param_type: ParamType::Continuous { min: 0.01, max: 0.3 } },
ParamDef { name: "no_cookies_path_count".into(), param_type: ParamType::Continuous { min: 5.0, max: 100.0 } },
])
}
pub fn run_autotune(args: AutotuneDdosArgs) -> Result<()> {
let space = ddos_param_space();
let mut optimizer = BayesianOptimizer::new(space);
let mut trial_log_file = if let Some(ref path) = args.trial_log {
Some(std::fs::File::create(path)?)
} else {
None
};
// Parse logs once upfront
eprintln!("Parsing logs from {}...", args.input);
let ip_states = parse_logs(&args.input)?;
eprintln!(" {} unique IPs", ip_states.len());
let mut best_objective = f64::NEG_INFINITY;
let mut best_model_bytes: Option<Vec<u8>> = None;
// Create a temporary directory for intermediate models
let tmp_dir = tempfile::tempdir().context("creating temp dir")?;
eprintln!("Starting DDoS autotune: {} trials, beta={}", args.trials, args.beta);
for trial_num in 1..=args.trials {
let params = optimizer.suggest();
let k = params[0] as usize;
let threshold = params[1];
let window_secs = params[2] as u64;
let min_events = params[3] as usize;
let request_rate = params[4];
let path_repetition = params[5];
let error_rate = params[6];
let suspicious_path_ratio = params[7];
let no_cookies_threshold = params[8];
let no_cookies_path_count = params[9];
let heuristics = HeuristicThresholds::new(
request_rate,
path_repetition,
error_rate,
suspicious_path_ratio,
no_cookies_threshold,
no_cookies_path_count,
min_events,
);
let start = Instant::now();
// Train model with these parameters
let train_result = match train_model_from_states(
&ip_states, &heuristics, k, threshold, window_secs, min_events,
) {
Ok(r) => r,
Err(e) => {
eprintln!(" trial {trial_num}: TRAIN FAILED ({e})");
optimizer.observe(params, 0.0, start.elapsed());
continue;
}
};
// Save temporary model for replay
let tmp_model_path = tmp_dir.path().join(format!("trial_{trial_num}.bin"));
let encoded = match bincode::serialize(&train_result.model) {
Ok(e) => e,
Err(e) => {
eprintln!(" trial {trial_num}: SERIALIZE FAILED ({e})");
optimizer.observe(params, 0.0, start.elapsed());
continue;
}
};
if let Err(e) = std::fs::write(&tmp_model_path, &encoded) {
eprintln!(" trial {trial_num}: WRITE FAILED ({e})");
optimizer.observe(params, 0.0, start.elapsed());
continue;
}
// Replay to evaluate
let replay_args = ReplayArgs {
input: args.input.clone(),
model_path: tmp_model_path.to_string_lossy().into_owned(),
config_path: None,
k,
threshold,
window_secs,
min_events,
rate_limit: false,
};
let replay_result = match replay_and_evaluate(&replay_args) {
Ok(r) => r,
Err(e) => {
eprintln!(" trial {trial_num}: REPLAY FAILED ({e})");
optimizer.observe(params, 0.0, start.elapsed());
continue;
}
};
let duration = start.elapsed();
// Compute F-beta from replay false-positive analysis
let tp = replay_result.true_positive_ips as f64;
let fp = replay_result.false_positive_ips as f64;
let total_blocked = replay_result.ddos_blocked_ips.len() as f64;
let fn_ = if total_blocked > 0.0 { 0.0 } else { 1.0 }; // We don't know true FN without ground truth
let objective = if tp + fp > 0.0 {
let precision = tp / (tp + fp);
let recall = if tp + fn_ > 0.0 { tp / (tp + fn_) } else { 0.0 };
let b2 = args.beta * args.beta;
if precision + recall > 0.0 {
(1.0 + b2) * precision * recall / (b2 * precision + recall)
} else {
0.0
}
} else {
0.0
};
eprintln!(
" trial {trial_num}/{}: fbeta={objective:.4} (k={k}, thr={threshold:.3}, win={window_secs}s, tp={}, fp={}) [{:.1}s]",
args.trials,
replay_result.true_positive_ips,
replay_result.false_positive_ips,
duration.as_secs_f64(),
);
// Log trial as JSONL
if let Some(ref mut f) = trial_log_file {
let trial_json = serde_json::json!({
"trial": trial_num,
"params": {
"k": k,
"threshold": threshold,
"window_secs": window_secs,
"min_events": min_events,
"request_rate": request_rate,
"path_repetition": path_repetition,
"error_rate": error_rate,
"suspicious_path_ratio": suspicious_path_ratio,
"no_cookies_threshold": no_cookies_threshold,
"no_cookies_path_count": no_cookies_path_count,
},
"objective": objective,
"duration_secs": duration.as_secs_f64(),
"true_positive_ips": replay_result.true_positive_ips,
"false_positive_ips": replay_result.false_positive_ips,
"ddos_blocked": replay_result.ddos_blocked,
"allowed": replay_result.allowed,
"attack_count": train_result.attack_count,
"normal_count": train_result.normal_count,
});
writeln!(f, "{}", trial_json)?;
}
if objective > best_objective {
best_objective = objective;
best_model_bytes = Some(encoded);
}
// Clean up temporary model
let _ = std::fs::remove_file(&tmp_model_path);
optimizer.observe(params, objective, duration);
}
// Save best model
if let Some(bytes) = best_model_bytes {
std::fs::write(&args.output, &bytes)?;
eprintln!("\nBest model saved to {}", args.output);
}
// Print summary
if let Some(best) = optimizer.best() {
eprintln!("\n═══ Autotune Results ═══════════════════════════════════════");
eprintln!(" Best trial: #{}", best.trial_num);
eprintln!(" Best F-beta: {:.4}", best.objective);
eprintln!(" Parameters:");
for (name, val) in best.param_names.iter().zip(best.params.iter()) {
eprintln!(" {:<30} = {:.6}", name, val);
}
eprintln!("\n Heuristics TOML snippet:");
eprintln!(" request_rate = {:.2}", best.params[4]);
eprintln!(" path_repetition = {:.4}", best.params[5]);
eprintln!(" error_rate = {:.4}", best.params[6]);
eprintln!(" suspicious_path_ratio = {:.4}", best.params[7]);
eprintln!(" no_cookies_threshold = {:.4}", best.params[8]);
eprintln!(" no_cookies_path_count = {:.1}", best.params[9]);
eprintln!(" min_events = {}", best.params[3] as usize);
eprintln!("\n Reproduce:");
eprintln!(
" cargo run -- train-ddos --input {} --output {} --k {} --threshold {:.4} --window-secs {} --min-events {} --heuristics <toml>",
args.input, args.output,
best.params[0] as usize, best.params[1],
best.params[2] as u64, best.params[3] as usize,
);
eprintln!("══════════════════════════════════════════════════════════");
}
Ok(())
}