create endpoints to retrieve and sign bill

src/billing_handler.rs

@@ -1,34 +1,63 @@
 use crate::model::AppState;
 
-use actix_web::web::Data;
-use actix_web::HttpResponse;
+use actix_web::web::{Data, Json};
+use actix_web::{get, post, HttpResponse, Responder};
 use anyhow::Context;
 use k256::elliptic_curve::generic_array::sequence::Lengthen;
 use serde_json::json;
 use tiny_keccak::{Hasher, Keccak};
 
-pub async fn billing_data(appstate: Data<AppState>) -> HttpResponse {
-    let mut execution_costs_gaurd = appstate.execution_costs.lock().unwrap();
+#[derive(Debug, serde::Deserialize)]
+pub struct SigningData {
+    nonce: String,
+    txhashes: Vec<String>,
+}
 
-    if execution_costs_gaurd.is_empty() {
-        return HttpResponse::BadRequest().body("No billing data available");
+#[get("/bill")]
+pub async fn get_bill(appstate: Data<AppState>) -> impl Responder {
+    let bill = appstate.execution_costs.lock().unwrap().clone();
+    if bill.is_empty() {
+        return HttpResponse::NoContent().body("No bill data available");
     }
 
-    let mut billing_data: Vec<u8> = Vec::new();
+    HttpResponse::Ok().json(json!({
+        "bill": bill,
+    }))
+}
+
+#[post("/sign")]
+pub async fn sign_data(appstate: Data<AppState>, data: Json<SigningData>) -> impl Responder {
+    let signing_data = data.into_inner();
+    if signing_data.nonce.is_empty() {
+        return HttpResponse::BadRequest().body("Nonce must not be empty");
+    }
 
-    for (tx_hash, cost) in execution_costs_gaurd.iter() {
-        let mut bytes32_tx_hash = [0u8; 32];
-        if let Err(err) = hex::decode_to_slice(&tx_hash[2..], &mut bytes32_tx_hash) {
-            return HttpResponse::InternalServerError()
-                .body(format!("Error decoding transaction hash: {:?}", err));
+    if signing_data.txhashes.is_empty() {
+        return HttpResponse::BadRequest().body("List of tx hashes must not be empty");
+    }
+
+    let mut signed_data: Vec<u8> = Vec::new();
+    for txhash in signing_data.txhashes {
+        if let Some(cost) = appstate.execution_costs.lock().unwrap().remove(&txhash) {
+            let mut bytes32_txhash = [0u8; 32];
+            if let Err(err) = hex::decode_to_slice(&txhash[2..], &mut bytes32_txhash) {
+                return HttpResponse::InternalServerError()
+                    .body(format!("Error decoding transaction hash: {:?}", err));
+            }
+
+            signed_data.append(&mut bytes32_txhash.to_vec());
+            signed_data.append(&mut cost.to_be_bytes().to_vec());
+        } else {
+            return HttpResponse::BadRequest().body(format!(
+                "{} tx hash doesn't exist in the current bill",
+                txhash
+            ));
         }
-
-        billing_data.append(&mut bytes32_tx_hash.to_vec());
-        billing_data.append(&mut cost.to_be_bytes().to_vec());
     }
+    signed_data.append(&mut signing_data.nonce.as_bytes().to_vec());
 
     let mut hasher = Keccak::v256();
-    hasher.update(&billing_data);
+    hasher.update(&signed_data);
 
     let mut hash = [0u8; 32];
     hasher.finalize(&mut hash);
@@ -41,13 +70,12 @@ pub async fn billing_data(appstate: Data<AppState>) -> HttpResponse {
         return HttpResponse::InternalServerError().body(format!("{}", sign.unwrap_err()));
     }
     let (rs, v) = sign.unwrap();
-    let signature = hex::encode(rs.to_bytes().append(27 + v.to_byte()).as_slice());
 
-    let billing_data = hex::encode(billing_data.as_slice());
-    execution_costs_gaurd.clear();
+    let signature = hex::encode(rs.to_bytes().append(27 + v.to_byte()).as_slice());
+    let signed_data = hex::encode(signed_data.as_slice());
 
     HttpResponse::Ok().json(json!({
-        "billing_data": billing_data,
+        "signed_data": signed_data,
         "signature": signature,
     }))
 }

src/contracts/billing_contract_abi.json

@@ -17,28 +17,5 @@
 		],
 		"stateMutability": "view",
 		"type": "function"
-	},
-	{
-		"inputs": [
-			{
-				"internalType": "bytes32[]",
-				"name": "_txhashes",
-				"type": "bytes32[]"
-			},
-			{
-				"internalType": "uint256[]",
-				"name": "_amounts",
-				"type": "uint256[]"
-			},
-			{
-				"internalType": "bytes",
-				"name": "signature",
-				"type": "bytes"
-			}
-		],
-		"name": "settle",
-		"outputs": [],
-		"stateMutability": "nonpayable",
-		"type": "function"
 	}
 ]

src/lib.rs

@@ -6,8 +6,12 @@ mod tests;
 pub mod workerd;
 
 use ethers::contract::abigen;
+use ethers::providers::{Http, Provider};
+
 abigen!(
     BillingContract,
     "src/contracts/billing_contract_abi.json",
     derives(serde::Serialize, serde::Deserialize)
 );
+
+type BillContract = BillingContract<Provider<Http>>;

src/main.rs

@@ -6,7 +6,7 @@ use serverless::cgroups::Cgroups;
 use serverless::model::AppState;
 use serverless::BillingContract;
 
-use actix_web::{web, App, HttpServer};
+use actix_web::{web, App, HttpResponse, HttpServer};
 use anyhow::{anyhow, Context};
 use clap::Parser;
 use ethers::providers::{Http, Provider};
@@ -116,7 +116,9 @@ async fn main() -> anyhow::Result<()> {
     let billing_server = HttpServer::new(move || {
         App::new()
             .app_data(app_data_clone.clone())
-            .default_service(web::to(serverless::billing_handler::billing_data))
+            .service(serverless::billing_handler::get_bill)
+            .service(serverless::billing_handler::sign_data)
+            .default_service(web::to(HttpResponse::NotFound))
     })
     .bind(("0.0.0.0", billing_port))
     .context(format!("could not bind to port {billing_port}"))?

src/model.rs

@@ -3,9 +3,7 @@ use std::sync::atomic::AtomicBool;
 use std::sync::Mutex;
 
 use crate::cgroups::Cgroups;
-use crate::BillingContract;
-
-use ethers::providers::{Http, Provider};
+use crate::BillContract;
 
 pub struct AppState {
     pub cgroups: Mutex<Cgroups>,
@@ -17,6 +15,6 @@ pub struct AppState {
     pub rpc: String,
     pub contract: String,
     pub signer: k256::ecdsa::SigningKey,
-    pub billing_contract: BillingContract<Provider<Http>>,
+    pub billing_contract: BillContract,
     pub execution_costs: Mutex<HashMap<String, u128>>,
 }

src/workerd.rs

@@ -2,7 +2,7 @@ use std::process::Child;
 use std::time::{Duration, Instant};
 
 use crate::cgroups::{Cgroups, CgroupsError};
-use crate::BillingContract;
+use crate::BillContract;
 
 use actix_web::{HttpRequest, HttpResponse};
 use anyhow::Error;
@@ -53,7 +53,7 @@ pub enum ServerlessError {
 
 async fn get_current_deposit(
     tx_hash: &str,
-    billing_contract: &BillingContract<Provider<Http>>,
+    billing_contract: &BillContract,
 ) -> Result<U256, Error> {
     let mut bytes32_tx_hash = [0u8; 32];
     hex::decode_to_slice(&tx_hash[2..], &mut bytes32_tx_hash)?;
@@ -88,7 +88,7 @@ pub async fn create_code_file(
     workerd_runtime_path: &str,
     rpc: &str,
     contract: &str,
-    billing_contract: &BillingContract<Provider<Http>>,
+    billing_contract: &BillContract,
 ) -> Result<(), ServerlessError> {
     // get tx data
     let mut tx_data = match get_transaction_data(tx_hash, rpc).await?["result"].take() {