From e4fda1a806785c4d2b44731364b91b680443c76b Mon Sep 17 00:00:00 2001
From: danda <dan-da@users.noreply.github.com>
Date: Wed, 22 May 2024 18:34:47 -0700
Subject: [PATCH] refactor: add anyhow, remove unwrap/expect

converts unwrap and expect calls in main.rs into anyhow .with_context()
calls to provide better error messages
---
 Cargo.lock  |  5 +++--
 Cargo.toml  |  3 ++-
 src/main.rs | 48 +++++++++++++++++++++++++++++-------------------
 3 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index bd856c3..ea5517f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -150,9 +150,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.82"
+version = "1.0.86"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f538837af36e6f6a9be0faa67f9a314f8119e4e4b5867c6ab40ed60360142519"
+checksum = "b3d1d046238990b9cf5bcde22a3fb3584ee5cf65fb2765f454ed428c7a0063da"
 
 [[package]]
 name = "arbitrary"
@@ -1819,6 +1819,7 @@ dependencies = [
 name = "neptune-explorer"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "axum 0.7.5",
  "boilerplate",
  "clap",
diff --git a/Cargo.toml b/Cargo.toml
index abb68cf..f00952d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,13 +21,14 @@ tarpc = { version = "^0.34", features = [
 ] }
 clap = "4.5.4"
 thiserror = "1.0.59"
-#boilerplate = { version = "1.0.0", features = ["axum"] }
 boilerplate = { version = "1.0.0" }
 html-escaper = "0.2.0"
 tower-http = { version = "0.5.2", features = ["fs"] }
 readonly = "0.2.12"
 url = "2.5.0"
 
+# only should be used inside main.rs, for the binary.
+anyhow = "1.0.86"
 
 [patch.crates-io]
 # 694f27daf78aade0ed0dc07e3babaab036cd5572 is tip of branch: master as of 2024-04-30
diff --git a/src/main.rs b/src/main.rs
index 6e49700..4e1ad53 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,4 @@
+use anyhow::Context;
 use axum::routing::get;
 use axum::routing::Router;
 use clap::Parser;
@@ -17,19 +18,24 @@ use std::net::Ipv4Addr;
 use std::net::SocketAddr;
 use std::sync::Arc;
 use tarpc::client;
-use tarpc::client::RpcError;
 use tarpc::context;
 use tarpc::tokio_serde::formats::Json as RpcJson;
 use tower_http::services::ServeDir;
 
 #[tokio::main]
-async fn main() -> Result<(), RpcError> {
-    let rpc_client = rpc_client().await;
-    let network = rpc_client.network(context::current()).await?;
+async fn main() -> Result<(), anyhow::Error> {
+    let rpc_client = rpc_client()
+        .await
+        .with_context(|| "Failed to create RPC client")?;
+    let network = rpc_client
+        .network(context::current())
+        .await
+        .with_context(|| "Failed calling neptune-core api: network")?;
     let genesis_digest = rpc_client
         .block_digest(context::current(), BlockSelector::Genesis)
-        .await?
-        .expect("Genesis block should be found");
+        .await
+        .with_context(|| "Failed calling neptune-core api: block_digest")?
+        .with_context(|| "neptune-core failed to provide a genesis block")?;
 
     let shared_state = Arc::new(AppState::from((
         network,
@@ -63,23 +69,27 @@ async fn main() -> Result<(), RpcError> {
         // add state
         .with_state(shared_state);
 
-    println!("Running on http://localhost:3000");
-    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
-    axum::serve(listener, app).await.unwrap();
+    let port = 3000;
+    let listener = tokio::net::TcpListener::bind(format!("0.0.0.0:{port}"))
+        .await
+        .with_context(|| format!("Failed to bind to port {port}"))?;
+
+    println!("Running on http://localhost:{port}");
+
+    axum::serve(listener, app)
+        .await
+        .with_context(|| "Axum server encountered an error")?;
     Ok(())
 }
 
-async fn rpc_client() -> RPCClient {
+async fn rpc_client() -> Result<RPCClient, anyhow::Error> {
     // Create connection to neptune-core RPC server
     let args: Config = Config::parse();
     let server_socket = SocketAddr::new(std::net::IpAddr::V4(Ipv4Addr::LOCALHOST), args.port);
-    let transport = tarpc::serde_transport::tcp::connect(server_socket, RpcJson::default).await;
-    let transport = match transport {
-        Ok(transp) => transp,
-        Err(err) => {
-            eprintln!("{err}");
-            panic!("Connection to neptune-core failed. Is a node running?");
-        }
-    };
-    RPCClient::new(client::Config::default(), transport).spawn()
+    let transport = tarpc::serde_transport::tcp::connect(server_socket, RpcJson::default)
+        .await
+        .with_context(|| {
+            format!("Failed to connect to neptune-core rpc service at {server_socket}")
+        })?;
+    Ok(RPCClient::new(client::Config::default(), transport).spawn())
 }