From e9d3c9aed078e58501dfb6690cf4188fd8de5d45 Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Mon, 7 Nov 2022 04:08:31 +0100
Subject: [PATCH] hunter/scheduler: add jitter to interval on no new posts

---
 Cargo.lock              | 48 +++++++++++++++++++++++++++++++++++++++++
 hunter/Cargo.toml       |  1 +
 hunter/src/scheduler.rs |  7 ++++--
 3 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4bc9d03..39c5b64 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -267,6 +267,7 @@ dependencies = [
  "cave",
  "chrono",
  "log",
+ "rand",
  "redis",
  "reqwest",
  "serde",
@@ -592,6 +593,17 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c05aeb6a22b8f62540c194aac980f2115af067bfe15a0734d7277a768d396b31"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+]
+
 [[package]]
 name = "h2"
 version = "0.3.15"
@@ -1076,6 +1088,12 @@ version = "0.3.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ac9a59f73473f1b8d852421e59e64809f025994837ef743615c6d0c5b305160"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.47"
@@ -1094,6 +1112,36 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "redis"
 version = "0.22.1"
diff --git a/hunter/Cargo.toml b/hunter/Cargo.toml
index cdfdb8a..8d165aa 100644
--- a/hunter/Cargo.toml
+++ b/hunter/Cargo.toml
@@ -13,3 +13,4 @@ redis = { version = "0.22", features = ["tokio-comp", "connection-manager"] }
 log = "0.4"
 systemd = "0.10"
 cave = { path = "../cave" }
+rand = "0.8"
diff --git a/hunter/src/scheduler.rs b/hunter/src/scheduler.rs
index a84ba9c..a0dc838 100644
--- a/hunter/src/scheduler.rs
+++ b/hunter/src/scheduler.rs
@@ -1,5 +1,6 @@
 use std::collections::{HashMap, BTreeMap};
 use std::time::Duration;
+use rand::{thread_rng, Rng};
 use tokio::time::Instant;
 
 const MIN_INTERVAL: Duration = Duration::from_secs(30);
@@ -56,8 +57,10 @@ impl Scheduler {
         let next_interval = match (new_post_ratio, mean_interval, last_interval) {
             (Some(new_post_ratio), Some(mean_interval), _) if new_post_ratio > 0. =>
                 mean_interval,
-            (_, _, Some(last_interval)) =>
-                2 * last_interval,
+            (_, _, Some(last_interval)) => {
+                let a = thread_rng().gen_range(2. .. 3.);
+                last_interval.mul_f64(a)
+            }
             _ =>
                 DEFAULT_INTERVAL,
         }.max(MIN_INTERVAL).min(MAX_INTERVAL);