node: Make writing blocks optional

Author: rustaceanrob

node/config_spec.toml

@@ -2,20 +2,32 @@
 name = "hintfile"
 type = "String"
 default = "\"./bitcoin.hints\".into()"
-doc = "The path to your `bitcoin.hints` file that will be used for IBD. Default is `./bitcoin.hints"
+doc = "The path to your `bitcoin.hints` file that will be used for IBD. Default is `./bitcoin.hints`"
 
 [[param]]
 name = "blocks_dir"
 type = "String"
-default = "\"./blockfiles\".into()"
-doc = "Directory where you would like to store the bitcoin blocks. Default `./blockfiles`"
+optional = true
+doc = "Optional directory to store the blocks. Used only to measure performance."
 
 [[param]]
 name = "network"
 type = "String"
 default = "\"bitcoin\".into()"
 doc = "The bitcoin network to operate on. Default `bitcoin`. Options are `bitcoin` or `signet`"
 
+[[param]]
+name = "min_blocks_per_sec"
+type = "f64"
+default = "3."
+doc = "The minimum rate a peer has to respond to block requests."
+
+[[param]]
+name = "tasks"
+type = "usize"
+default = "32"
+doc = "The number of tasks to download blocks. Default is 64. Each task uses two OS threads."
+
 [[param]]
 name = "ping_timeout"
 type = "u64"
@@ -40,14 +52,3 @@ type = "u64"
 default = "2"
 doc = "The maximum time (seconds) to write to a TCP stream until the connection is killed."
 
-[[param]]
-name = "min_blocks_per_sec"
-type = "f64"
-default = "3."
-doc = "The minimum rate a peer has to respond to block requests."
-
-[[param]]
-name = "tasks"
-type = "usize"
-default = "32"
-doc = "The number of tasks to download blocks. Default is 64. Each task uses two OS threads."

node/src/bin/ibd.rs

@@ -45,8 +45,10 @@ fn main() {
     let mut hintfile = File::open(hint_path).expect("invalid hintfile path");
     let hints = Arc::new(Hints::from_file(&mut hintfile));
     elapsed_time(hintfile_start_time);
-    let block_file_path = PathBuf::from(&blocks_dir);
-    std::fs::create_dir(&block_file_path).expect("could not create block file directory");
+    let block_file_path = blocks_dir.map(PathBuf::from);
+    if let Some(block_file_path) = block_file_path.as_ref() {
+        std::fs::create_dir(block_file_path).expect("could not create block file directory");
+    }
     let stop_hash =
         consensus::deserialize::<BlockHash>(&hints.stop_hash()).expect("stop hash is not valid");
     tracing::info!("Assume valid hash: {stop_hash}");
@@ -88,7 +90,7 @@ fn main() {
                 block_per_sec,
                 ping_timeout,
                 network,
-                &block_file_path,
+                block_file_path,
                 chain,
                 &hints,
                 peers,

node/src/lib.rs

@@ -3,7 +3,7 @@ use std::{
     fs::File,
     io::Write,
     net::{IpAddr, Ipv4Addr, SocketAddr},
-    path::Path,
+    path::PathBuf,
     sync::{
         mpsc::{Receiver, Sender},
         Arc, Mutex,
@@ -170,7 +170,7 @@ pub fn get_blocks_for_range(
     blocks_per_sec: f64,
     _ping_timeout: Duration,
     network: Network,
-    block_dir: &Path,
+    block_dir: Option<PathBuf>,
     chain: Arc<ChainstateManager>,
     hints: &Hints,
     peers: Arc<Mutex<Vec<SocketAddr>>>,
@@ -222,19 +222,22 @@ pub fn get_blocks_for_range(
                     let unspent_indexes: HashSet<u64> =
                         hints.get_indexes(block_height).into_iter().collect();
                     // tracing::info!("{task_id} -> {block_height}:{hash}");
-                    let file_path = block_dir.join(format!("{hash}.block"));
-                    let file = File::create_new(file_path);
-                    let mut file = match file {
-                        Ok(file) => file,
-                        Err(e) => {
-                            tracing::warn!("Conflicting open files at: {}", block_height);
-                            tracing::warn!("{e}");
-                            panic!("files cannot conflict");
-                        }
-                    };
-                    let block_bytes = consensus::serialize(&block);
-                    file.write_all(&block_bytes)
-                        .expect("failed to write block file");
+                    if let Some(block_dir) = block_dir.as_ref() {
+                        let file_path = block_dir.join(format!("{hash}.block"));
+                        let file = File::create_new(file_path);
+                        let mut file = match file {
+                            Ok(file) => file,
+                            Err(e) => {
+                                tracing::warn!("Conflicting open files at: {}", block_height);
+                                tracing::warn!("{e}");
+                                panic!("files cannot conflict");
+                            }
+                        };
+                        let block_bytes = consensus::serialize(&block);
+                        file.write_all(&block_bytes)
+                            .expect("failed to write block file");
+                        file.sync_data().expect("could not sync file with OS");
+                    }
                     // tracing::info!("Wrote {hash} to file");
                     let (_, transactions) = block.into_parts();
                     let mut output_index = 0;