Use different artifact names for wasm/js in debug builds

Cargo.toml

@@ -27,6 +27,7 @@ re_analytics = { path = "crates/re_analytics", version = "0.2.0" }
 re_arrow_store = { path = "crates/re_arrow_store", version = "0.2.0" }
 re_build_build_info = { path = "crates/re_build_build_info", version = "0.2.0" }
 re_build_info = { path = "crates/re_build_info", version = "0.2.0" }
+re_build_web_viewer = { path = "crates/re_build_web_viewer", version = "0.2.0" }
 re_data_store = { path = "crates/re_data_store", version = "0.2.0" }
 re_error = { path = "crates/re_error", version = "0.2.0" }
 re_format = { path = "crates/re_format", version = "0.2.0" }

crates/re_build_web_viewer/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "re_build_web_viewer"
+authors.workspace = true
+description = "Build the rerun web-viewer Wasm from source"
+edition.workspace = true
+homepage.workspace = true
+include.workspace = true
+license.workspace = true
+publish = true
+readme = "README.md"
+repository.workspace = true
+rust-version.workspace = true
+version.workspace = true
+
+[package.metadata.docs.rs]
+all-features = true
+
+
+[dependencies]
+cargo_metadata = "0.15"

crates/re_build_web_viewer/README.md

@@ -0,0 +1,13 @@
+# `re_build_web_viewer`
+
+Binary and library for building the Rerun web viewer.
+
+This is also called by the `build.rs` of `re_web_server`.
+
+```
+cargo r -p re_build_web_viewer -- --debug
+````
+
+```
+cargo r -p re_build_web_viewer -- --release
+````

crates/re_build_web_viewer/src/lib.rs

@@ -0,0 +1,146 @@
+use cargo_metadata::camino::Utf8PathBuf;
+
+fn target_directory() -> Utf8PathBuf {
+    let metadata = cargo_metadata::MetadataCommand::new()
+        .manifest_path("./Cargo.toml")
+        .features(cargo_metadata::CargoOpt::NoDefaultFeatures)
+        .exec()
+        .unwrap();
+    metadata.target_directory
+}
+
+/// Build `re_viewer` as Wasm, generate .js bindings for it, and place it all into the `./web_viewer` folder.
+pub fn build(release: bool) {
+    eprintln!("Building web viewer wasm…");
+    eprintln!("We assume you've already run ./scripts/setup_web.sh");
+
+    let crate_name = "re_viewer";
+
+    // Where we tell cargo to build to.
+    // We want this to be different from the default target folder
+    // in order to support recursive cargo builds (calling `cargo` from within a `build.rs`).
+    let target_wasm_dir = Utf8PathBuf::from(format!("{}_wasm", target_directory()));
+
+    // Repository root
+    let root_dir = target_wasm_dir.parent().unwrap();
+
+    // Where we will place the final .wasm and .js artifacts.
+    let build_dir = root_dir.join("web_viewer");
+
+    assert!(
+        build_dir.exists(),
+        "Failed to find dir {build_dir}. CWD: {:?}, CARGO_MANIFEST_DIR: {:?}",
+        std::env::current_dir(),
+        std::env!("CARGO_MANIFEST_DIR")
+    );
+
+    let target_name = if release {
+        crate_name.to_owned()
+    } else {
+        format!("{crate_name}_debug")
+    };
+
+    // The two files we are building:
+    let wasm_path = build_dir.join(format!("{target_name}_bg.wasm"));
+    let js_path = build_dir.join(format!("{target_name}.js"));
+
+    // Clean old versions:
+    std::fs::remove_file(wasm_path.clone()).ok();
+    std::fs::remove_file(js_path).ok();
+
+    // --------------------------------------------------------------------------------
+    eprintln!("Compiling rust to wasm in {target_wasm_dir}…");
+
+    let mut cmd = std::process::Command::new("cargo");
+    cmd.args([
+        "build",
+        "--target-dir",
+        target_wasm_dir.as_str(),
+        "-p",
+        crate_name,
+        "--lib",
+        "--target",
+        "wasm32-unknown-unknown",
+    ]);
+    if release {
+        cmd.arg("--release");
+    }
+
+    // This is required to enable the web_sys clipboard API which egui_web uses
+    // https://rustwasm.github.io/wasm-bindgen/api/web_sys/struct.Clipboard.html
+    // https://rustwasm.github.io/docs/wasm-bindgen/web-sys/unstable-apis.html
+    cmd.env("RUSTFLAGS", "--cfg=web_sys_unstable_apis");
+
+    // When executing this script from a Rust build script, do _not_, under any circumstances,
+    // allow pre-encoded `RUSTFLAGS` to leak into the current environment.
+    // These pre-encoded flags are generally generated by Cargo itself when loading its
+    // configuration from e.g. `$CARGO_HOME/config.toml`; which means they will contain
+    // values that only make sense for the native target host, not for a wasm build.
+    cmd.env("CARGO_ENCODED_RUSTFLAGS", "");
+
+    eprintln!("> {cmd:?}");
+    let status = cmd
+        .current_dir(root_dir)
+        .status()
+        .expect("Failed to build Wasm");
+    assert!(status.success(), "Failed to build Wasm");
+
+    // --------------------------------------------------------------------------------
+    eprintln!("Generating JS bindings for wasm…");
+
+    let build = if release { "release" } else { "debug" };
+
+    let target_wasm_path = target_wasm_dir
+        .join("wasm32-unknown-unknown")
+        .join(build)
+        .join(format!("{crate_name}.wasm"));
+
+    let mut cmd = std::process::Command::new("wasm-bindgen");
+    cmd.args([
+        target_wasm_path.as_str(),
+        "--out-dir",
+        build_dir.as_str(),
+        "--out-name",
+        target_name.as_str(),
+        "--no-modules",
+        "--no-typescript",
+    ]);
+    if !release {
+        cmd.arg("--debug");
+    }
+
+    eprintln!("> {cmd:?}");
+    let status = cmd
+        .current_dir(root_dir)
+        .status()
+        .expect("Failed to run wasm-bindgen");
+    assert!(status.success(), "Failed to run wasm-bindgen");
+
+    // --------------------------------------------------------------------------------
+    // Optimize the wasm
+
+    if release {
+        eprintln!("Optimizing wasm with wasm-opt…");
+
+        // to get wasm-opt:  apt/brew/dnf install binaryen
+        let mut cmd = std::process::Command::new("wasm-opt");
+
+        // TODO(emilk): add `-g` to keep debug symbols; useful for profiling release builds in the in-browser profiler.
+        cmd.args([
+            wasm_path.as_str(),
+            "-O2",
+            "--fast-math",
+            "-o",
+            wasm_path.as_str(),
+        ]);
+
+        eprintln!("> {cmd:?}");
+        let status = cmd
+            .current_dir(root_dir)
+            .status()
+            .expect("Failed to run wasm-opt");
+        assert!(status.success(), "Failed to run wasm-opt");
+    }
+
+    eprintln!("Finished {wasm_path}");
+}

crates/re_build_web_viewer/src/main.rs

@@ -0,0 +1,46 @@
+use std::process::ExitCode;
+
+fn main() -> ExitCode {
+    let mut release = None;
+
+    for arg in std::env::args().skip(1) {
+        match arg.as_str() {
+            "--help" => {
+                print_help();
+                return ExitCode::SUCCESS;
+            }
+            "--debug" => {
+                assert!(release.is_none(), "Can't set both --release and --debug");
+                release = Some(false);
+            }
+            "--release" => {
+                assert!(release.is_none(), "Can't set both --release and --debug");
+                release = Some(true);
+            }
+            _ => {
+                print_help();
+                return ExitCode::FAILURE;
+            }
+        }
+    }
+
+    let Some(release) = release else {
+        eprintln!("You need to pass either --debug or --release");
+        return ExitCode::FAILURE;
+    };
+
+    re_build_web_viewer::build(release);
+    ExitCode::SUCCESS
+}
+
+fn print_help() {
+    eprintln!(
+        r"Build the web-viewer.
+
+  --help:    Print this help text
+  --debug:   Build a debug binary
+  --release: Compile for release, and run wasm-opt.
+             NOTE: --release also removes debug symbols which are otherwise useful for in-browser profiling.
+"
+    );
+}

crates/re_web_server/Cargo.toml

@@ -54,3 +54,4 @@ re_analytics = { workspace = true, optional = true }
 [build-dependencies]
 glob = "0.3.0"
 cargo_metadata = "0.15"
+re_build_web_viewer.workspace = true