Add debug build of calc-fee that outputs more information

README.md

@@ -27,6 +27,16 @@ yarn
 yarn start
 ```
 
+### Fee Calculation Debugging
+
+It is possible to get more information about the fee calculation process logged to
+the console. Because this fee calculation happens in the statically compiled web assembly part
+a re-compile with the proper environment variable set is necessary:
+
+```
+FEE_DEBUG=1 yarn
+```
+
 ### Available paths
 
 Block IDs may take two forms: a non-negative decimal integer that denotes the block _height_ **or**

calc-fee/Cargo.toml

@@ -12,13 +12,15 @@ description = "Calculate extrinsic fees off-chain"
 crate-type = ["cdylib"]
 
 [features]
-debug = ["console_error_panic_hook"]
+debug = ["console_error_panic_hook", "console_log"]
 
 [dependencies]
 wasm-bindgen = { version = "0.2", default_features = false, features = ["serde-serialize"] }
 serde_derive = { version = "1", default_features = false }
 serde = { version = "1", default_features = false }
 console_error_panic_hook = { version = "0.1", optional = true }
+console_log = { version = "0.2.0", optional = true }
+log = "0.4.8"
 
 [dependencies.sp-arithmetic]
 version = "2.0.0-rc3"

calc-fee/build.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+
+if [ -z ${FEE_DEBUG} ]; then
+    wasm-pack build --target nodejs --scope polkadot "$SCRIPT_DIR"
+else
+    echo "Fee debugging enabled"
+    wasm-pack build --target nodejs --scope polkadot "$SCRIPT_DIR" -- --features debug
+fi

calc-fee/src/debug.rs

@@ -0,0 +1,8 @@
+#[cfg(feature = "debug")]
+pub fn setup() {
+	console_error_panic_hook::set_once();
+	console_log::init_with_level(log::Level::Debug).ok();
+}
+
+#[cfg(not(feature = "debug"))]
+pub fn setup() {}

calc-fee/src/lib.rs

@@ -1,10 +1,11 @@
-mod panic;
+mod debug;
 
+use core::str::FromStr;
+use log::info;
 use serde_derive::Deserialize;
 use sp_arithmetic::{FixedI128, FixedPointNumber, Perbill};
 use sp_arithmetic_legacy::Fixed128 as Fixed128Legacy;
 use wasm_bindgen::prelude::*;
-use core::str::FromStr;
 
 type Balance = u128;
 type Weight = u64;
@@ -18,13 +19,15 @@ pub struct JSCoefficient {
 	degree: u8,
 }
 
+#[derive(Debug)]
 struct Coefficient {
 	coeff_integer: Balance,
 	coeff_frac: Perbill,
 	negative: bool,
 	degree: u8,
 }
 
+#[derive(Debug)]
 enum Multiplier {
 	Current((FixedI128, bool)),
 	Legacy(Fixed128Legacy),
@@ -48,13 +51,14 @@ impl Multiplier {
 				} else {
 					mult.0.saturating_mul_acc_int(balance)
 				}
-			},
+			}
 			Self::Legacy(mult) => mult.saturated_multiply_accumulate(balance),
 		}
 	}
 }
 
 #[wasm_bindgen]
+#[derive(Debug)]
 pub struct CalcFee {
 	polynomial: Vec<Coefficient>,
 	multiplier: Multiplier,
@@ -72,44 +76,50 @@ impl CalcFee {
 		fixed128_bug: bool,
 		fixed128_legacy: bool,
 	) -> Self {
-		panic::set_hook();
+		debug::setup();
+
 		let polynomial: Vec<Coefficient> = {
 			let poly: Vec<JSCoefficient> = polynomial.into_serde().unwrap();
-			poly.iter().map(|c|
-				Coefficient {
+			poly.iter()
+				.map(|c| Coefficient {
 					coeff_integer: Balance::from_str(&c.coeffInteger).unwrap(),
 					coeff_frac: Perbill::from_parts(c.coeffFrac),
 					negative: c.negative,
-					degree: c.degree
-				}
-			)
-			.collect()
+					degree: c.degree,
+				})
+				.collect()
 		};
 		let multiplier = Multiplier::new(
 			i128::from_str(multiplier).unwrap(),
 			fixed128_legacy,
-			fixed128_bug
+			fixed128_bug,
 		);
 		let per_byte_fee = Balance::from_str(per_byte_fee).unwrap();
 		let base_fee = weight_to_fee(&extrinsic_base_weight, &polynomial);
-		Self {
+		let calc = Self {
 			polynomial,
 			multiplier,
 			per_byte_fee,
 			base_fee,
-		}
+		};
+		info!("CalcFee::withParams -> {:#?}", calc);
+		calc
 	}
 
 	pub fn calc_fee(&self, weight: Weight, len: u32) -> String {
-		panic::set_hook();
-
 		let len_fee = self.per_byte_fee.saturating_mul(len.into());
-		let unadjusted_weight_fee = weight_to_fee(&weight, &self.polynomial);
+		let weight_fee = weight_to_fee(&weight, &self.polynomial);
 
-		let adjustable_fee = len_fee.saturating_add(unadjusted_weight_fee);
+		let adjustable_fee = len_fee.saturating_add(weight_fee);
 		let adjusted_fee = self.multiplier.calc(adjustable_fee);
 
-		self.base_fee.saturating_add(adjusted_fee).to_string()
+		let result = self.base_fee.saturating_add(adjusted_fee);
+
+		info!("calc_fee: ({}, {}) -> len_fee: {} weight_fee: {} adjustable_fee: {} \
+			adjusted_fee: {} result: {}",
+			weight, len, len_fee, weight_fee, adjustable_fee, adjusted_fee, result);
+
+		result.to_string()
 	}
 }
 

package.json

@@ -4,7 +4,7 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "preinstall": "wasm-pack build --target nodejs --scope polkadot calc-fee",
+    "preinstall": "./calc-fee/build.sh",
     "postinstall": "yarn upgrade @polkadot/calc-fee",
     "build": "tsc",
     "lint": "tsc && eslint . --ext ts",

src/ApiHandler.ts

@@ -68,6 +68,9 @@ export default class ApiHandler {
 		]);
 
 		const { parentHash, number, stateRoot, extrinsicsRoot } = block.header;
+
+		api.registry.setMetadata(await api.rpc.state.getMetadata(parentHash));
+
 		const onInitialize = { events: [] as SanitizedEvent[] };
 		const onFinalize = { events: [] as SanitizedEvent[] };