added gas consumption stdout to zkvm program

cmd/ethrex_l2/src/commands/prove.rs

@@ -1,7 +1,6 @@
 use clap::Args;
 use ethrex_l2::utils::test_data_io::{generate_program_input, read_chain_file, read_genesis_file};
 use ethrex_prover_lib::prover::Prover;
-use log::info;
 
 #[derive(Args)]
 pub(crate) struct Command {
@@ -33,8 +32,12 @@ impl Command {
 
         let mut prover = Prover::new();
         prover.prove(program_input).expect("proving failed");
-
-        info!("Successfully proven block");
+        println!(
+            "Total gas consumption: {}",
+            prover
+                .get_gas()
+                .expect("failed to deserialize gas consumption")
+        );
         Ok(())
     }
 }

crates/l2/prover/src/prover.rs

@@ -61,6 +61,12 @@ impl<'a> Prover<'a> {
         Ok(())
     }
 
+    pub fn get_gas(&self) -> Result<u64, Box<dyn std::error::Error>> {
+        Ok(risc0_zkvm::serde::from_slice(
+            &self.stdout[..8], // first 8 bytes
+        )?)
+    }
+
     pub fn get_commitment(
         receipt: &risc0_zkvm::Receipt,
     ) -> Result<ProgramOutput, Box<dyn std::error::Error>> {

crates/l2/prover/zkvm/interface/guest/src/main.rs

@@ -31,6 +31,13 @@ fn main() {
     let receipts = execute_block(&block, &mut state).expect("failed to execute block");
     validate_gas_used(&receipts, &block.header).expect("invalid gas used");
 
+    env::write(
+        &receipts
+            .last()
+            .expect("no receipts found")
+            .cumulative_gas_used,
+    );
+
     let account_updates = get_state_transitions(&mut state);
 
     // Update tries and calculate final state root hash