feat: config inheriting

Author: transmissions11

configs/aggressive.toml

@@ -0,0 +1,11 @@
+inherits = "default.toml"
+
+[rate_limiting]
+initial_ratelimit = 250
+ratelimit_thresholds = [
+    [500, 1_000],
+    [5_000, 2_500],
+    [50_000, 10_000],
+    [200_000, 50_000],
+    [400_000, 100_000],
+]

configs/default.toml

@@ -37,9 +37,6 @@ ratelimit_thresholds = [
     [300_000, 15_000],  # NUM_ACCOUNTS * 12
     [350_000, 20_000],  # NUM_ACCOUNTS * 14
     [400_000, 25_000],  # NUM_ACCOUNTS * 16
-    [450_000, 35_000],  # NUM_ACCOUNTS * 18
-    [550_000, 50_000],  # NUM_ACCOUNTS * 22
-    [600_000, 100_000],  # NUM_ACCOUNTS * 24
 ]
 
 [workers]

crescendo/src/config.rs

@@ -3,6 +3,8 @@ use std::sync::OnceLock;
 
 use serde::{Deserialize, Serialize};
 
+use crate::utils::merge_toml_values;
+
 /// Global configuration instance for the application.
 static CONFIG_INSTANCE: OnceLock<Config> = OnceLock::new();
 
@@ -30,8 +32,29 @@ pub struct Config {
 impl Config {
     pub fn from_file(path: &PathBuf) -> Result<Self, Box<dyn std::error::Error>> {
         let config_str = std::fs::read_to_string(path)?;
-        let config: Config = toml::from_str(&config_str)?;
-        Ok(config)
+        let mut config_value: toml::Value = toml::from_str(&config_str)?;
+
+        // Check if this config inherits from another.
+        if let Some(inherits) = config_value.get("inherits").and_then(|v| v.as_str()) {
+            // Load the inherited config recursively.
+            let inherited_config = Self::from_file(&{
+                if let Some(parent) = path.parent() {
+                    parent.join(inherits)
+                } else {
+                    PathBuf::from(inherits)
+                }
+            })?;
+
+            // Merge the current config over the inherited one.
+            config_value = merge_toml_values(toml::Value::try_from(inherited_config)?, config_value);
+        }
+
+        // Remove the inherits field before deserializing.
+        if let Some(table) = config_value.as_table_mut() {
+            table.remove("inherits");
+        }
+
+        Ok(config_value.try_into()?)
     }
 }
 

crescendo/src/utils.rs

@@ -69,3 +69,25 @@ pub fn format_ranges(nums: &[usize]) -> String {
 
     ranges.join(", ")
 }
+
+/// Merge two TOML values, with `overlay` taking precedence over `base`.
+pub fn merge_toml_values(base: toml::Value, overlay: toml::Value) -> toml::Value {
+    match (base, overlay) {
+        (toml::Value::Table(mut base_table), toml::Value::Table(overlay_table)) => {
+            for (key, overlay_value) in overlay_table {
+                match base_table.get(&key) {
+                    Some(base_value) if base_value.is_table() && overlay_value.is_table() => {
+                        // Recursively merge nested tables
+                        base_table.insert(key, merge_toml_values(base_value.clone(), overlay_value));
+                    }
+                    _ => {
+                        // Replace the value
+                        base_table.insert(key, overlay_value);
+                    }
+                }
+            }
+            toml::Value::Table(base_table)
+        }
+        (_, overlay) => overlay, // For non-table values, overlay completely replaces base.
+    }
+}