add tracing to the treehouse as an instrumenting profiler

to create a trace of the treehouse's startup, use `--trace file.json`

Cargo.lock

@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "addr2line"
@@ -438,15 +438,6 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7c74b8349d32d297c9134b8c88677813a227df8f779daa29bfc29c183fe3dca6"
 
-[[package]]
-name = "copy_dir"
-version = "0.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "543d1dd138ef086e2ff05e3a48cf9da045da2033d16f8538fd76b86cd49b2ca3"
-dependencies = [
- "walkdir",
-]
-
 [[package]]
 name = "core-foundation-sys"
 version = "0.8.7"
@@ -553,19 +544,6 @@ version = "1.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"
 
-[[package]]
-name = "env_logger"
-version = "0.10.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4cd405aab171cb85d6735e5c8d9db038c17d3ca007a4d2c25f337935c3d90580"
-dependencies = [
- "humantime",
- "is-terminal",
- "log",
- "regex",
- "termcolor",
-]
-
 [[package]]
 name = "equivalent"
 version = "1.0.1"
@@ -754,12 +732,6 @@ version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
 
-[[package]]
-name = "hermit-abi"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fbf6a919d6cf397374f7dfeeea91d974c7c0a7221d0d0f4f20d859d329e53fcc"
-
 [[package]]
 name = "http"
 version = "1.1.0"
@@ -806,12 +778,6 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df3b46402a9d5adb4c86a0cf463f42e19994e3ee891101b1841f30a545cb49a9"
 
-[[package]]
-name = "humantime"
-version = "2.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
-
 [[package]]
 name = "hyper"
 version = "1.5.1"
@@ -1070,17 +1036,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "is-terminal"
-version = "0.4.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "261f68e344040fbd0edea105bef17c66edf46f984ddb1115b775ce31be948f4b"
-dependencies = [
- "hermit-abi 0.4.0",
- "libc",
- "windows-sys 0.52.0",
-]
-
 [[package]]
 name = "is_terminal_polyfill"
 version = "1.70.1"
@@ -1132,6 +1087,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
 [[package]]
 name = "lebe"
 version = "0.5.2"
@@ -1209,6 +1170,15 @@ dependencies = [
  "imgref",
 ]
 
+[[package]]
+name = "matchers"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8263075bb86c5a1b1427b5ae862e8889656f126e9f77c484496e8b47cf5c5558"
+dependencies = [
+ "regex-automata 0.1.10",
+]
+
 [[package]]
 name = "matchit"
 version = "0.7.3"
@@ -1259,7 +1229,7 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "80e04d1dcff3aae0704555fe5fee3bcfaf3d1fdf8a7e521d5b9d2b42acb52cec"
 dependencies = [
- "hermit-abi 0.3.9",
+ "hermit-abi",
  "libc",
  "wasi",
  "windows-sys 0.52.0",
@@ -1287,6 +1257,16 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0676bb32a98c1a483ce53e500a81ad9c3d5b3f7c920c28c24e9cb0980d0b5bc8"
 
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "num-bigint"
 version = "0.4.6"
@@ -1352,6 +1332,12 @@ version = "1.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1261fe7e33c73b354eab43b1273a57c8f967d0391e80353e51f764ac02cf6775"
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.3"
@@ -1641,8 +1627,17 @@ checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-automata",
+ "regex-automata 0.4.9",
- "regex-syntax",
+ "regex-syntax 0.8.5",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c230d73fb8d8c1b9c0b3135c5142a8acee3a0558fb8db5cf1cb65f8d7862132"
+dependencies = [
+ "regex-syntax 0.6.29",
 ]
 
 [[package]]
@@ -1653,9 +1648,15 @@ checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-syntax",
+ "regex-syntax 0.8.5",
 ]
 
+[[package]]
+name = "regex-syntax"
+version = "0.6.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
+
 [[package]]
 name = "regex-syntax"
 version = "0.8.5"
@@ -1686,15 +1687,6 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f3cb5ba0dc43242ce17de99c180e96db90b235b8a9fdc9543c96d2209116bd9f"
 
-[[package]]
-name = "same-file"
-version = "1.0.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
-dependencies = [
- "winapi-util",
-]
-
 [[package]]
 name = "scopeguard"
 version = "1.2.0"
@@ -1775,6 +1767,15 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -1915,6 +1916,16 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b9ef9bad013ada3808854ceac7b46812a6465ba368859a37e2100283d2d719c"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+]
+
 [[package]]
 name = "tiff"
 version = "0.9.1"
@@ -2048,9 +2059,32 @@ checksum = "c3523ab5a71916ccf420eebdf5521fcef02141234bbc0b8a49f2fdc4544364ef"
 dependencies = [
  "log",
  "pin-project-lite",
+ "tracing-attributes",
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-attributes"
+version = "0.1.27"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34704c8d6ebcbc939824180af020566b01a7c01f80641264eba0999f6c2b6be7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "tracing-chrome"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf0a738ed5d6450a9fb96e86a23ad808de2b727fd1394585da5cdd6788ffe724"
+dependencies = [
+ "serde_json",
+ "tracing-core",
+ "tracing-subscriber",
+]
+
 [[package]]
 name = "tracing-core"
 version = "0.1.32"
@@ -2058,6 +2092,36 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c06d3da6113f116aaee68e4d601191614c9053067f9ab7f6edbcb161237daa54"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad0f048c97dbd9faa9b7df56362b8ebcaa52adb06b498c050d2f4e32f90a7a8b"
+dependencies = [
+ "matchers",
+ "nu-ansi-term",
+ "once_cell",
+ "regex",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -2071,16 +2135,12 @@ dependencies = [
  "chrono",
  "clap",
  "codespan-reporting",
- "copy_dir",
  "dashmap",
- "env_logger",
  "git2",
  "handlebars",
- "http-body",
  "image",
  "indexmap",
  "jotdown",
- "log",
  "rand",
  "rayon",
  "regex",
@@ -2088,10 +2148,11 @@ dependencies = [
  "serde_json",
  "tokio",
  "toml_edit 0.19.15",
+ "tracing",
+ "tracing-chrome",
+ "tracing-subscriber",
  "treehouse-format",
  "ulid",
- "url",
- "walkdir",
 ]
 
 [[package]]
@@ -2176,6 +2237,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
 [[package]]
 name = "vcpkg"
 version = "0.2.15"
@@ -2194,16 +2261,6 @@ version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b928f33d975fc6ad9f86c8f283853ad26bdd5b10b7f1542aa2fa15e2289105a"
 
-[[package]]
-name = "walkdir"
-version = "2.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "29790946404f91d9c5d06f9874efddea1dc06c5efe94541a7d6863108e3a5e4b"
-dependencies = [
- "same-file",
- "winapi-util",
-]
-
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
@@ -2281,6 +2338,22 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "53a85b86a771b1c87058196170769dd264f66c0782acf1ae6cc51bfd64b39082"
 
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
 [[package]]
 name = "winapi-util"
 version = "0.1.9"
@@ -2290,6 +2363,12 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
 [[package]]
 name = "windows-core"
 version = "0.52.0"

Cargo.toml

@@ -3,6 +3,6 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.dependencies]
-log = "0.4.20"
+tracing = "0.1.40"
 
 treehouse-format = { path = "crates/treehouse-format" }

crates/treehouse/Cargo.toml

@@ -14,16 +14,12 @@ blake3 = "1.5.3"
 chrono = "0.4.35"
 clap = { version = "4.3.22", features = ["derive"] }
 codespan-reporting = "0.11.1"
-copy_dir = "0.1.3"
 dashmap = "6.1.0"
-env_logger = "0.10.0"
 git2 = { version = "0.19.0", default-features = false, features = ["vendored-libgit2"] }
 handlebars = "4.3.7"
-http-body = "1.0.0"
 image = "0.25.5"
 indexmap = { version = "2.2.6", features = ["serde"] }
 jotdown = { version = "0.4.1", default-features = false }
-log = { workspace = true }
 rand = "0.8.5"
 rayon = "1.10.0"
 regex = "1.10.3"
@@ -31,6 +27,7 @@ serde = { version = "1.0.183", features = ["derive"] }
 serde_json = "1.0.105"
 tokio = { version = "1.32.0", features = ["full"] }
 toml_edit = { version = "0.19.14", features = ["serde"] }
-walkdir = "2.3.3"
+tracing.workspace = true
+tracing-chrome = "0.7.2"
+tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
 ulid = "1.0.0"
-url = "2.5.0"

crates/treehouse/src/cli.rs

@@ -2,12 +2,18 @@ pub mod fix;
 pub mod serve;
 pub mod wc;
 
+use std::path::PathBuf;
+
 use clap::{Args, Parser, Subcommand};
 
 use crate::vfs::VPathBuf;
 
 #[derive(Parser)]
 pub struct ProgramArgs {
+    /// Emit a Chrome trace to the given file.
+    #[clap(long)]
+    pub trace: Option<PathBuf>,
+
     #[clap(subcommand)]
     pub command: Command,
 }

crates/treehouse/src/cli/fix.rs

@@ -2,7 +2,7 @@ use std::ops::{ControlFlow, Range};
 
 use anyhow::{anyhow, Context};
 use codespan_reporting::diagnostic::Diagnostic;
-use log::{error, info};
+use tracing::{error, info};
 use treehouse_format::ast::Branch;
 
 use crate::{

crates/treehouse/src/cli/serve.rs

@@ -14,9 +14,9 @@ use axum::{
     routing::get,
     Router,
 };
-use log::info;
 use serde::Deserialize;
 use tokio::net::TcpListener;
+use tracing::{info, instrument};
 
 use crate::generate::Sources;
 use crate::vfs::asynch::AsyncDir;
@@ -36,6 +36,7 @@ struct Server {
     target: AsyncDir,
 }
 
+#[instrument(skip(sources, target))]
 pub async fn serve(sources: Arc<Sources>, target: AsyncDir, port: u16) -> anyhow::Result<()> {
     let app = Router::new()
         .route("/", get(index)) // needed explicitly because * does not match empty paths
@@ -62,12 +63,13 @@ fn get_content_type(extension: &str) -> Option<&'static str> {
     }
 }
 
-#[derive(Deserialize)]
+#[derive(Debug, Deserialize)]
 struct VfsQuery {
     #[serde(rename = "v")]
     content_version: Option<String>,
 }
 
+#[instrument(skip(state))]
 async fn get_static_file(path: &str, query: &VfsQuery, state: &Server) -> Option<Response> {
     let vpath = VPath::try_new(path).ok()?;
     let content = state.target.content(vpath).await?;
@@ -123,6 +125,7 @@ async fn four_oh_four(State(state): State<Arc<Server>>) -> Response {
     system_page(&state.target, system::FOUR_OH_FOUR, StatusCode::NOT_FOUND).await
 }
 
+#[instrument(skip(state))]
 async fn branch(RawQuery(named_id): RawQuery, State(state): State<Arc<Server>>) -> Response {
     if let Some(named_id) = named_id {
         let branch_id = state

crates/treehouse/src/config.rs

@@ -1,8 +1,8 @@
 use std::{collections::HashMap, ops::ControlFlow};
 
 use anyhow::{anyhow, Context};
-use log::{debug, error};
 use serde::{Deserialize, Serialize};
+use tracing::{debug, error, info_span, instrument};
 
 use crate::{
     html::highlight::{
@@ -99,6 +99,7 @@ pub enum Markup {
 }
 
 impl Config {
+    #[instrument(name = "Config::autopopulate_emoji", skip(self))]
     pub fn autopopulate_emoji(&mut self, dir: &dyn Dir) -> anyhow::Result<()> {
         vfs::walk_dir_rec(dir, VPath::ROOT, &mut |path| {
             if path.extension().is_some_and(is_image_file) {
@@ -115,6 +116,7 @@ impl Config {
         Ok(())
     }
 
+    #[instrument(name = "Config::autopopulate_pics", skip(self))]
     pub fn autopopulate_pics(&mut self, dir: &dyn Dir) -> anyhow::Result<()> {
         vfs::walk_dir_rec(dir, VPath::ROOT, &mut |path| {
             if path.extension().is_some_and(is_image_file) {
@@ -156,13 +158,13 @@ impl Config {
     }
 
     /// Loads all syntax definition files.
+    #[instrument(name = "Config::load_syntaxes", skip(self))]
     pub fn load_syntaxes(&mut self, dir: &dyn Dir) -> anyhow::Result<()> {
         vfs::walk_dir_rec(dir, VPath::ROOT, &mut |path| {
             if path.extension() == Some("json") {
                 let name = path
                     .file_stem()
                     .expect("syntax file name should have a stem due to the .json extension");
-                debug!("loading syntax {name:?}");
 
                 let result: Result<Syntax, _> = dir
                     .content(path)
@@ -171,10 +173,12 @@ impl Config {
                         String::from_utf8(b).context("syntax .json contains invalid UTF-8")
                     })
                     .and_then(|s| {
+                        let _span = info_span!("Config::load_syntaxes::parse").entered();
                         serde_json::from_str(&s).context("could not deserialize syntax file")
                     });
                 match result {
                     Ok(syntax) => {
+                        let _span = info_span!("Config::load_syntaxes::compile", ?name).entered();
                         let compiled = compile_syntax(&syntax);
                         self.syntaxes.insert(name.to_owned(), compiled);
                     }

crates/treehouse/src/generate.rs

@@ -8,8 +8,8 @@ use codespan_reporting::diagnostic::Diagnostic;
 use dir_helper::DirHelper;
 use handlebars::{handlebars_helper, Handlebars};
 use include_static_helper::IncludeStaticHelper;
-use log::{debug, error, info};
 use serde::Serialize;
+use tracing::{debug, error, info, info_span, instrument};
 
 use crate::{
     config::Config,
@@ -81,10 +81,12 @@ fn create_handlebars(site: &str, static_: DynDir) -> Handlebars<'static> {
     handlebars
 }
 
+#[instrument(skip(handlebars))]
 fn load_templates(handlebars: &mut Handlebars, dir: &dyn Dir) {
     vfs::walk_dir_rec(dir, VPath::ROOT, &mut |path| {
         if path.extension() == Some("hbs") {
             if let Some(content) = dir.content(path).and_then(|b| String::from_utf8(b).ok()) {
+                let _span = info_span!("register_template", ?path).entered();
                 if let Err(err) = handlebars.register_template_string(path.as_str(), content) {
                     error!("in template: {err}");
                 }
@@ -94,6 +96,7 @@ fn load_templates(handlebars: &mut Handlebars, dir: &dyn Dir) {
     });
 }
 
+#[instrument(skip(treehouse, config, source, target_path, tree_path))]
 fn parse_tree(
     treehouse: &mut Treehouse,
     config: &Config,
@@ -125,6 +128,7 @@ fn parse_tree(
     }
 }
 
+#[instrument(skip(config, dirs))]
 fn parse_trees(
     config: &Config,
     dirs: &Dirs,
@@ -143,8 +147,6 @@ fn parse_trees(
                 let tree_path = path.with_extension("");
                 let target_path = path.with_extension("html");
 
-                debug!("tree file: {path}");
-
                 match parse_tree(
                     &mut treehouse,
                     config,
@@ -174,6 +176,7 @@ fn parse_trees(
     Ok((treehouse, parsed_trees))
 }
 
+#[instrument(skip(sources, handlebars))]
 fn generate_simple_template(
     sources: &Sources,
     handlebars: &Handlebars,
@@ -202,6 +205,7 @@ fn generate_simple_template_or_error(
     }
 }
 
+#[instrument(skip(sources, dirs, handlebars, parsed_tree), fields(root_key = parsed_tree.root_key))]
 fn generate_tree(
     sources: &Sources,
     dirs: &Dirs,
@@ -214,12 +218,15 @@ fn generate_tree(
         &parsed_tree.root_key,
     );
 
-    let mut tree = String::new();
     let roots = sources
         .treehouse
         .roots
         .get(&parsed_tree.root_key)
         .expect("tree should have been added to the treehouse");
+
+    let tree = {
+        let _span = info_span!("generate_tree::branches_to_html").entered();
+        let mut tree = String::new();
         branches_to_html(
             &mut tree,
             &sources.treehouse,
@@ -228,6 +235,8 @@ fn generate_tree(
             parsed_tree.file_id,
             &roots.branches,
         );
+        tree
+    };
 
     let base_template_data = BaseTemplateData {
         config: &sources.config,
@@ -270,6 +279,7 @@ fn generate_tree(
         "template {template_name} does not exist"
     );
 
+    let _span = info_span!("handlebars::render").entered();
     handlebars
         .render(&template_name, &template_data)
         .context("template rendering failed")
@@ -297,7 +307,8 @@ pub struct Sources {
 
 impl Sources {
     pub fn load(dirs: &Dirs) -> anyhow::Result<Self> {
-        info!("loading config");
+        let config = {
+            let _span = info_span!("load_config").entered();
             let mut config: Config = toml_edit::de::from_str(
                 &dirs
                     .root
@@ -310,14 +321,11 @@ impl Sources {
             config.autopopulate_emoji(&*dirs.emoji)?;
             config.autopopulate_pics(&*dirs.pic)?;
             config.load_syntaxes(&*dirs.syntax)?;
+            config
+        };
 
-        info!("parsing tree files");
         let (treehouse, parsed_trees) = parse_trees(&config, dirs)?;
-
-        info!("constructing navigation map");
         let navigation_map = NavigationMap::build(&treehouse, "index");
-
-        info!("constructing import map");
         let import_map = ImportMap::generate(
             &config.site,
             &Cd::new(dirs.static_.clone(), VPathBuf::new("js")),
@@ -342,6 +350,7 @@ struct DirIndex {
 }
 
 impl DirIndex {
+    #[instrument(name = "DirIndex::new", skip(paths))]
     pub fn new<'a>(paths: impl Iterator<Item = &'a VPath>) -> Self {
         let mut root = DirIndex::default();
 
@@ -387,6 +396,7 @@ impl TreehouseDir {
 }
 
 impl Dir for TreehouseDir {
+    #[instrument("TreehouseDir::dir", skip(self))]
     fn dir(&self, path: &VPath) -> Vec<DirEntry> {
         // NOTE: This does not include simple templates, because that's not really needed right now.
 
@@ -410,9 +420,8 @@ impl Dir for TreehouseDir {
             .collect()
     }
 
+    #[instrument("TreehouseDir::content", skip(self))]
     fn content(&self, path: &VPath) -> Option<Vec<u8>> {
-        debug!("content({path})");
-
         let path = if path.is_root() {
             VPath::new_const("index")
         } else {

crates/treehouse/src/history.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
 use indexmap::IndexMap;
-use log::debug;
+use tracing::debug;
 
 #[derive(Debug, Default, Clone)]
 pub struct History {

crates/treehouse/src/html/breadcrumbs.rs

@@ -1,9 +1,12 @@
 use std::{borrow::Cow, fmt::Write};
 
+use tracing::instrument;
+
 use crate::config::Config;
 
 use super::{navmap::NavigationMap, EscapeAttribute};
 
+#[instrument(skip(config, navigation_map))]
 pub fn breadcrumbs_to_html(
     config: &Config,
     navigation_map: &NavigationMap,

crates/treehouse/src/html/highlight/compiled.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 
-use log::error;
 use regex::{Regex, RegexBuilder};
+use tracing::{error, instrument};
 
 use super::{RegexFlag, Syntax, TokenTypes};
 
@@ -43,6 +43,7 @@ pub struct CompiledKeyword {
     pub only_replaces: Option<TokenId>,
 }
 
+#[instrument(skip(syntax))]
 pub fn compile_syntax(syntax: &Syntax) -> CompiledSyntax {
     let mut token_names = vec!["default".into()];
     let mut get_token_id = |name: &str| -> TokenId {

crates/treehouse/src/html/navmap.rs

@@ -1,5 +1,7 @@
 use std::collections::HashMap;
 
+use tracing::instrument;
+
 use crate::{
     state::Treehouse,
     tree::{attributes::Content, SemaBranchId},
@@ -33,6 +35,7 @@ pub struct NavigationMap {
 }
 
 impl NavigationMap {
+    #[instrument(name = "NavigationMap::build", skip(treehouse))]
     pub fn build(treehouse: &Treehouse, root_tree_path: &str) -> Self {
         let mut builder = NavigationMapBuilder::default();
 

crates/treehouse/src/import_map.rs

@@ -2,6 +2,7 @@ use std::ops::ControlFlow;
 
 use indexmap::IndexMap;
 use serde::{Deserialize, Serialize};
+use tracing::instrument;
 
 use crate::vfs::{self, Dir, VPathBuf};
 
@@ -17,6 +18,7 @@ pub struct ImportRoot {
 }
 
 impl ImportMap {
+    #[instrument(name = "ImportMap::generate", skip(import_roots))]
     pub fn generate(site: &str, root: &dyn Dir, import_roots: &[ImportRoot]) -> Self {
         let mut import_map = ImportMap {
             imports: IndexMap::new(),

crates/treehouse/src/main.rs

@@ -1,10 +1,13 @@
-use std::fs;
+use std::fs::{self, File};
 use std::path::PathBuf;
 use std::sync::Arc;
 
 use anyhow::Context;
 use clap::Parser;
-use log::error;
+use tracing::{error, info_span};
+use tracing_subscriber::fmt::format::FmtSpan;
+use tracing_subscriber::layer::SubscriberExt as _;
+use tracing_subscriber::util::SubscriberInitExt as _;
 use treehouse::cli::serve::serve;
 use treehouse::dirs::Dirs;
 use treehouse::generate::{self, Sources};
@@ -50,9 +53,10 @@ fn vfs_sources() -> anyhow::Result<DynDir> {
     Ok(root.to_dyn())
 }
 
-async fn fallible_main() -> anyhow::Result<()> {
+async fn fallible_main(
-    let args = ProgramArgs::parse();
+    args: ProgramArgs,
-
+    flush_guard: Option<tracing_chrome::FlushGuard>,
+) -> anyhow::Result<()> {
     let src = vfs_sources()?;
     let dirs = Arc::new(Dirs {
         root: src.clone(),
@@ -69,8 +73,12 @@ async fn fallible_main() -> anyhow::Result<()> {
             generate: _,
             serve: serve_args,
         } => {
+            let _span = info_span!("load").entered();
             let sources = Arc::new(Sources::load(&dirs).context("failed to load sources")?);
             let target = generate::target(dirs, sources.clone());
+            drop(_span);
+            drop(flush_guard);
+
             serve(sources, AsyncDir::new(target), serve_args.port).await?;
         }
 
@@ -93,11 +101,26 @@ async fn fallible_main() -> anyhow::Result<()> {
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    env_logger::Builder::new()
+    let args = ProgramArgs::parse();
-        .filter_module("treehouse", log::LevelFilter::Debug)
+
+    let (chrome_layer, flush_guard) = args
+        .trace
+        .as_ref()
+        .map(|path| {
+            tracing_chrome::ChromeLayerBuilder::new()
+                .file(path)
+                .include_args(true)
+                .build()
+        })
+        .unzip();
+
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::EnvFilter::new("treehouse=trace"))
+        .with(tracing_subscriber::fmt::layer().with_writer(std::io::stderr))
+        .with(chrome_layer)
         .init();
 
-    match fallible_main().await {
+    match fallible_main(args, flush_guard).await {
         Ok(_) => (),
         Err(error) => error!("fatal: {error:?}"),
     }

crates/treehouse/src/parse.rs

@@ -1,12 +1,14 @@
 use std::{ops::Range, str::FromStr};
 
 use codespan_reporting::diagnostic::{Diagnostic, Label, LabelStyle, Severity};
+use tracing::instrument;
 use treehouse_format::ast::Roots;
 
 use crate::state::{toml_error_to_diagnostic, FileId, TomlError, Treehouse};
 
 pub struct ErrorsEmitted;
 
+#[instrument(skip(treehouse))]
 pub fn parse_tree_with_diagnostics(
     treehouse: &mut Treehouse,
     file_id: FileId,

crates/treehouse/src/tree.rs

@@ -4,6 +4,7 @@ pub mod mini_template;
 use std::ops::Range;
 
 use codespan_reporting::diagnostic::{Diagnostic, Label, LabelStyle, Severity};
+use tracing::instrument;
 use treehouse_format::{
     ast::{Branch, Roots},
     pull::BranchKind,
@@ -44,6 +45,10 @@ pub struct SemaRoots {
 }
 
 impl SemaRoots {
+    #[instrument(
+        name = "SemaRoots::from_roots",
+        skip(treehouse, diagnostics, config, roots)
+    )]
     pub fn from_roots(
         treehouse: &mut Treehouse,
         diagnostics: &mut Vec<Diagnostic<FileId>>,

crates/treehouse/src/vfs/content_cache.rs

@@ -4,8 +4,8 @@ use std::{
 };
 
 use dashmap::DashMap;
-use log::debug;
 use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
+use tracing::{info_span, instrument};
 
 use super::{walk_dir_rec, Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
 
@@ -27,8 +27,8 @@ impl<T> ContentCache<T>
 where
     T: Dir + Send + Sync,
 {
+    #[instrument(name = "ContentCache::warm_up", skip(self))]
     pub fn warm_up(&self) {
-        debug!("warm_up({self:?})");
         let mut paths = vec![];
         walk_dir_rec(&self.inner, VPath::ROOT, &mut |path| {
             paths.push(path.to_owned());
@@ -47,8 +47,11 @@ where
         self.inner.dir(path)
     }
 
+    #[instrument(name = "ContentCache::content", skip(self))]
     fn content(&self, path: &VPath) -> Option<Vec<u8>> {
         self.cache.get(path).map(|x| x.clone()).or_else(|| {
+            let _span = info_span!("cache_miss").entered();
+
             let content = self.inner.content(path);
             if let Some(content) = &content {
                 self.cache.insert(path.to_owned(), content.clone());

crates/treehouse/src/vfs/content_version_cache.rs

@@ -1,6 +1,7 @@
 use std::fmt::{self, Debug};
 
 use dashmap::DashMap;
+use tracing::{info_span, instrument};
 
 use super::{Dir, DirEntry, EditPath, ImageSize, VPath, VPathBuf};
 
@@ -30,8 +31,11 @@ where
         self.inner.content(path)
     }
 
+    #[instrument(name = "Blake3ContentVersionCache::content_version", skip(self))]
     fn content_version(&self, path: &VPath) -> Option<String> {
         self.cache.get(path).map(|x| x.clone()).or_else(|| {
+            let _span = info_span!("cache_miss").entered();
+
             let version = self.inner.content(path).map(|content| {
                 let hash = blake3::hash(&content).to_hex();
                 format!("b3-{}", &hash[0..8])

crates/treehouse/src/vfs/edit.rs

@@ -1,7 +1,7 @@
 use std::{error::Error, fmt, future::Future, path::PathBuf};
 
-use log::{debug, error, info};
 use tokio::task::JoinSet;
+use tracing::{debug, error, info};
 
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct EditPath {

crates/treehouse/src/vfs/image_size_cache.rs

@@ -2,7 +2,7 @@ use std::{fmt, io::Cursor};
 
 use anyhow::Context;
 use dashmap::DashMap;
-use log::{debug, warn};
+use tracing::{debug, info_span, instrument, warn};
 
 use crate::config;
 
@@ -33,7 +33,6 @@ where
                     .with_guessed_format()
                     .context("cannot guess image format")?;
                 let (width, height) = reader.into_dimensions()?;
-                debug!("image_size({path}) = ({width}, {height})");
                 return Ok(Some(ImageSize { width, height }));
             }
         }
@@ -58,11 +57,14 @@ where
         self.inner.content_version(path)
     }
 
+    #[instrument("ImageSizeCache::image_size", skip(self))]
     fn image_size(&self, path: &VPath) -> Option<ImageSize> {
         self.cache.get(path).map(|x| *x).or_else(|| {
+            let _span = info_span!("cache_miss").entered();
+
             let image_size = self
                 .compute_image_size(path)
-                .inspect_err(|err| warn!("compute_image_size({path}) failed: {err:?}"))
+                .inspect_err(|err| warn!(%path, ?err, "compute_image_size failure"))
                 .ok()
                 .flatten();
             if let Some(image_size) = image_size {

crates/treehouse/src/vfs/overlay.rs

@@ -1,5 +1,7 @@
 use std::fmt;
 
+use tracing::instrument;
+
 use super::{Dir, DirEntry, DynDir, EditPath, ImageSize, VPath, VPathBuf};
 
 pub struct Overlay {
@@ -14,6 +16,7 @@ impl Overlay {
 }
 
 impl Dir for Overlay {
+    #[instrument("Overlay::dir", skip(self))]
     fn dir(&self, path: &VPath) -> Vec<DirEntry> {
         let mut dir = self.base.dir(path);
         dir.append(&mut self.overlay.dir(path));

crates/treehouse/src/vfs/physical.rs

@@ -1,6 +1,6 @@
 use std::path::{Path, PathBuf};
 
-use log::error;
+use tracing::{error, instrument};
 
 use super::{Dir, DirEntry, EditPath, VPath, VPathBuf};
 
@@ -16,6 +16,7 @@ impl PhysicalDir {
 }
 
 impl Dir for PhysicalDir {
+    #[instrument("PhysicalDir::dir", skip(self))]
     fn dir(&self, vpath: &VPath) -> Vec<DirEntry> {
         let physical = self.root.join(physical_path(vpath));
         if !physical.is_dir() {
@@ -63,6 +64,7 @@ impl Dir for PhysicalDir {
         None
     }
 
+    #[instrument("PhysicalDir::content", skip(self))]
     fn content(&self, path: &VPath) -> Option<Vec<u8>> {
         std::fs::read(self.root.join(physical_path(path)))
             .inspect_err(|err| error!("{self:?} cannot read file at vpath {path:?}: {err:?}",))