Log consensus-key signer address if specified (#2158)

## Linked Issues/PRs
<!-- List of related issues/PRs -->
Closes #2132


## Description

Checks if the consensus key is available when running the node, in which
case it logs its corresponding public key address

<!-- List of detailed changes -->

- [x] added two functions `public_key` and `address` to the
`signer::SignMode` struct.
- [x] changed main binary to display the result of SignMode::address
when the consensus key is specified

## Manual testing: 
```lang=bash
./target/debug/fuel-core run --db-type in-memory --debug
```

Relevant output: 
```
2024-09-04T15:30:22.400412Z  INFO fuel_core_bin::cli::run: 324: Consensus signer is specified and its address is 22ec92c3105c942a6640bdc4e4907286ec4728e8cfc0d8ac59aad4d8e1ccaefb
```

## Checklist
- [ ] Breaking changes are clearly marked as such in the PR description
and changelog
- [x] New behavior is reflected in tests
- [x] [The specification](https://github.com/FuelLabs/fuel-specs/)
matches the implemented behavior (link update PR if changes are needed)

### Before requesting review
- [x] I have reviewed the code myself
- [ ] I have created follow-up issues caused by this PR and linked them
here

### After merging, notify other teams

[Add or remove entries as needed]

- [ ] [Rust SDK](https://github.com/FuelLabs/fuels-rs/)
- [ ] [Sway compiler](https://github.com/FuelLabs/sway/)
- [ ] [Platform
documentation](https://github.com/FuelLabs/devrel-requests/issues/new?assignees=&labels=new+request&projects=&template=NEW-REQUEST.yml&title=%5BRequest%5D%3A+)
(for out-of-organization contributors, the person merging the PR will do
this)
- [ ] Someone else?

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [2135](https://github.com/FuelLabs/fuel-core/pull/2135): Added metrics logging for number of blocks served over the p2p req/res protocol.
 - [2155](https://github.com/FuelLabs/fuel-core/pull/2155): Added trait declaration for block committer data
 - [2142](https://github.com/FuelLabs/fuel-core/pull/2142): Added benchmarks for varied forms of db lookups to assist in optimizations.
+- [2158](https://github.com/FuelLabs/fuel-core/pull/2158): Log the public address of the signing key, if it is specified
 
 ## [Version 0.35.0]
 

bin/fuel-core/src/cli/run.rs

@@ -354,7 +354,18 @@ impl Command {
                 );
                 consensus_signer = SignMode::Key(Secret::new(key.into()));
             }
-        }
+        };
+
+        if let Ok(signer_address) = consensus_signer.address() {
+            if let Some(address) = signer_address {
+                info!(
+                    "Consensus signer is specified and its address is {}",
+                    address
+                );
+            }
+        } else {
+            warn!("Consensus Signer is specified but it was not possible to retrieve its address");
+        };
 
         if consensus_signer.is_available() && trigger == Trigger::Never {
             warn!("Consensus key configured but block production is disabled!");

crates/services/consensus_module/poa/src/signer.rs

@@ -18,6 +18,11 @@ use fuel_core_types::{
         },
         primitives::SecretKeyWrapper,
     },
+    fuel_crypto::PublicKey,
+    fuel_tx::{
+        Address,
+        Input,
+    },
     fuel_vm::Signature,
     secrecy::{
         ExposeSecret,
@@ -68,6 +73,34 @@ impl SignMode {
         };
         Ok(Consensus::PoA(PoAConsensus::new(poa_signature)))
     }
+
+    /// Returns the public key of the block producer, if any
+    pub fn public_key(&self) -> anyhow::Result<Option<PublicKey>> {
+        match self {
+            SignMode::Unavailable => Ok(None),
+            SignMode::Key(secret_key) => {
+                Ok(Some(secret_key.expose_secret().public_key()))
+            }
+
+            #[cfg(feature = "aws-kms")]
+            SignMode::Kms {
+                cached_public_key_bytes,
+                ..
+            } => {
+                use k256::pkcs8::DecodePublicKey;
+
+                let k256_public_key =
+                    k256::PublicKey::from_public_key_der(cached_public_key_bytes)?;
+                Ok(Some(PublicKey::from(k256_public_key)))
+            }
+        }
+    }
+
+    /// Returns the address of the block producer, if any
+    pub fn address(&self) -> anyhow::Result<Option<Address>> {
+        let address = self.public_key()?.as_ref().map(Input::owner);
+        Ok(address)
+    }
 }
 
 #[cfg(feature = "aws-kms")]
@@ -140,6 +173,8 @@ async fn sign_with_kms(
 
 #[cfg(test)]
 mod tests {
+    use std::str::FromStr;
+
     use super::*;
     use fuel_core_types::fuel_crypto::SecretKey;
     use rand::{
@@ -173,4 +208,51 @@ mod tests {
             .is_available())
         };
     }
+
+    // The tests are against a keypair generated using fuel-core-keygen, which has
+    // been tweaked to display the public key associated with a keypair.
+    // The keypair used in these tests is the following:
+    // {
+    //    "address:"e2f3f5109c56eec359c124cbf25f35dcc1495b0bbdac5848e0ff37a86fe69a6d",
+    //    "public_key":"9ab6229de634056cdc67dfba26e6a06e4ba082693ea30395e5994b113ab6c6e3189a12a10d8fb08d1d28f7117ca34f6b16c5132acd9570de6e7a005f6bbd8f3d",
+    //    "secret":"2708b7bad8b5b52d031e5795c1d1995660185f464900cbd593328eb433bdb7f6","type":"block-production"
+    // }
+    #[test]
+    fn public_key() {
+        assert_eq!(SignMode::Unavailable.public_key().unwrap(), None);
+
+        let secret_key = SecretKey::from_str(
+            "2708b7bad8b5b52d031e5795c1d1995660185f464900cbd593328eb433bdb7f6",
+        )
+        .expect("Secret key construction should not fail");
+
+        let public_key = "9ab6229de634056cdc67dfba26e6a06e4ba082693ea30395e5994b113ab6c6e3189a12a10d8fb08d1d28f7117ca34f6b16c5132acd9570de6e7a005f6bbd8f3d";
+
+        let derived_public_key = SignMode::Key(Secret::new(secret_key.into()))
+            .public_key()
+            .expect("Public key derivation should not fail")
+            .expect("Public key derivation should yield a defined value")
+            .to_string();
+
+        assert_eq!(public_key, &derived_public_key);
+    }
+
+    #[test]
+    fn address() {
+        assert_eq!(SignMode::Unavailable.address().unwrap(), None);
+
+        let secret_key = SecretKey::from_str(
+            "2708b7bad8b5b52d031e5795c1d1995660185f464900cbd593328eb433bdb7f6",
+        )
+        .expect("Secret key construction should not fail");
+
+        let address = "e2f3f5109c56eec359c124cbf25f35dcc1495b0bbdac5848e0ff37a86fe69a6d";
+        let derived_address = SignMode::Key(Secret::new(secret_key.into()))
+            .address()
+            .expect("Address derivation should not fail")
+            .expect("Address derivation should yield a defined value")
+            .to_string();
+
+        assert_eq!(address, &derived_address);
+    }
 }