Expose graph option for fwdctl

Dump was already dumping the keys and values, so we should keep
that, but added in the option of calling the dump() method that
produces a digraph of the trie.

Additional changes: hashes and binary values are truncated to 6
characters, followed by an ellipsis, and the graphs are rotated
so they go left-right. This makes the graphs a lot prettier.

Partial paths can still be long but truncating them seemed like
a bad idea, so they are the only long string in the boxes now.

firewood/src/merkle.rs

@@ -76,7 +76,12 @@ macro_rules! write_attributes {
                     write!($writer, " val={}", string)?
                 }
                 _ => {
-                    write!($writer, " val={}", hex::encode($value))?;
+                    let hex = hex::encode($value);
+                    if hex.len() > 6 {
+                        write!($writer, " val={:.6}...", hex)?;
+                    } else {
+                        write!($writer, " val={}", hex)?;
+                    }
                 }
             }
         }
@@ -341,7 +346,10 @@ impl<T: HashedNodeReader> Merkle<T> {
         seen: &mut HashSet<LinearAddress>,
         writer: &mut dyn Write,
     ) -> Result<(), MerkleError> {
-        write!(writer, "  {addr}[label=\"addr:{addr:?} hash:{hash:?}")?;
+        write!(writer, "  {addr}[label=\"addr:{addr:?}")?;
+        if let Some(hash) = hash {
+            write!(writer, " hash:{hash:.6?}...")?;
+        }
 
         match &*self.read_node(addr)? {
             Node::Branch(b) => {
@@ -378,7 +386,7 @@ impl<T: HashedNodeReader> Merkle<T> {
 
     pub fn dump(&self) -> Result<String, MerkleError> {
         let mut result = vec![];
-        writeln!(result, "digraph Merkle {{")?;
+        writeln!(result, "digraph Merkle {{\n  rankdir=LR;")?;
         if let Some((root_addr, root_hash)) = self.nodestore.root_address_and_hash()? {
             writeln!(result, " root -> {root_addr}")?;
             let mut seen = HashSet::new();

fwdctl/src/graph.rs

@@ -0,0 +1,27 @@
+// Copyright (C) 2023, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE.md for licensing terms.
+
+use clap::Args;
+use firewood::db::{Db, DbConfig};
+use firewood::v2::api;
+use std::io::stdout;
+
+#[derive(Debug, Args)]
+pub struct Options {
+    /// The database path (if no path is provided, return an error). Defaults to firewood.
+    #[arg(
+        value_name = "DB_NAME",
+        default_value_t = String::from("firewood"),
+        help = "Name of the database"
+    )]
+    pub db: String,
+}
+
+pub(super) async fn run(opts: &Options) -> Result<(), api::Error> {
+    log::debug!("dump database {:?}", opts);
+    let cfg = DbConfig::builder().truncate(false);
+
+    let db = Db::new(opts.db.clone(), cfg.build()).await?;
+    db.dump(&mut stdout())?;
+    Ok(())
+}

fwdctl/src/main.rs

@@ -8,6 +8,7 @@ pub mod create;
 pub mod delete;
 pub mod dump;
 pub mod get;
+pub mod graph;
 pub mod insert;
 pub mod root;
 
@@ -44,6 +45,8 @@ enum Commands {
     Root(root::Options),
     /// Dump contents of key/value store
     Dump(dump::Options),
+    /// Produce a dot file of the database
+    Graph(graph::Options),
 }
 
 #[tokio::main]
@@ -62,5 +65,6 @@ async fn main() -> Result<(), api::Error> {
         Commands::Delete(opts) => delete::run(opts).await,
         Commands::Root(opts) => root::run(opts).await,
         Commands::Dump(opts) => dump::run(opts).await,
+        Commands::Graph(opts) => graph::run(opts).await,
     }
 }

storage/src/trie_hash.rs

@@ -32,7 +32,8 @@ impl AsRef<[u8]> for TrieHash {
 
 impl Debug for TrieHash {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        write!(f, "{}", hex::encode(self.0))
+        let width = f.precision().unwrap_or_default();
+        write!(f, "{:.*}", width, hex::encode(self.0))
     }
 }