Add env-filter-explorer example

examples/Cargo.toml

@@ -11,15 +11,22 @@ default = []
 [dev-dependencies]
 
 # tracing crates
-tracing = { path = "../tracing", version = "0.2"}
-tracing-core = { path = "../tracing-core", version = "0.2"}
+tracing = { path = "../tracing", version = "0.2" }
+tracing-core = { path = "../tracing-core", version = "0.2" }
 tracing-error = { path = "../tracing-error" }
 tracing-flame = { path = "../tracing-flame" }
 tracing-tower = { version = "0.1.0", path = "../tracing-tower" }
-tracing-subscriber = { path = "../tracing-subscriber", version = "0.3", features = ["json", "env-filter"] }
-tracing-futures = { version = "0.3", path = "../tracing-futures", features = ["futures-01"] }
-tracing-attributes =  { path = "../tracing-attributes", version = "0.2"}
-tracing-log = { path = "../tracing-log", version = "0.2", features = ["env_logger"] }
+tracing-subscriber = { path = "../tracing-subscriber", version = "0.3", features = [
+    "json",
+    "env-filter",
+] }
+tracing-futures = { version = "0.3", path = "../tracing-futures", features = [
+    "futures-01",
+] }
+tracing-attributes = { path = "../tracing-attributes", version = "0.2" }
+tracing-log = { path = "../tracing-log", version = "0.2", features = [
+    "env_logger",
+] }
 tracing-serde = { path = "../tracing-serde" }
 tracing-appender = { path = "../tracing-appender" }
 tracing-journald = { path = "../tracing-journald" }
@@ -44,12 +51,18 @@ humantime = "2.1.0"
 log = "0.4.17"
 
 # inferno example
-inferno = "0.11.6"
+inferno = "0.12.1"
 tempfile = "3.3.0"
 
 # fmt examples
 snafu = "0.6.10"
 thiserror = "1.0.31"
 
+# env-filter-explorer example
+ansi-to-tui = "7.0.0"
+ratatui = "0.29.0"
+crossterm = "0.28.1"
+tui-textarea = "0.7.0"
+
 [lints]
 workspace = true

examples/examples/env-filter-explorer.rs

@@ -0,0 +1,180 @@
+use std::{
+    fmt,
+    io::{self},
+    sync::{Arc, Mutex},
+};
+
+use ansi_to_tui::IntoText;
+use crossterm::event;
+use ratatui::{
+    layout::{Constraint, Layout},
+    text::Text,
+    widgets::Block,
+    DefaultTerminal, Frame,
+};
+use tracing_subscriber::fmt::MakeWriter;
+use tui_textarea::{Input, Key, TextArea};
+
+fn main() -> io::Result<()> {
+    let terminal = ratatui::init();
+    let result = run(terminal);
+    ratatui::restore();
+    result
+}
+
+const PRESET_FILTERS: &[&str] = &[
+    "trace",
+    "debug",
+    "info",
+    "warn",
+    "error",
+    "[with_fields]",
+    "[with_fields{foo}]",
+    "[with_fields{bar}]",
+    "[with_fields{foo=42}]",
+    "[with_fields{bar=bar}]",
+    "[with_fields{foo=99}]",
+    "[with_fields{bar=nope}]",
+    "[with_fields{nonexistent}]",
+    "other_crate=info",
+    "other_crate=debug",
+    "trace,other_crate=warn",
+    "warn,other_crate=info",
+];
+
+fn run(mut terminal: DefaultTerminal) -> io::Result<()> {
+    let mut textarea = TextArea::new(vec!["trace".to_string()]);
+    let title = "Env Filter Explorer. <Esc> to quit, <Up>/<Down> to select preset";
+    textarea.set_block(Block::bordered().title(title));
+    let mut preset_index: usize = 0;
+    loop {
+        terminal.draw(|frame| render(frame, &textarea))?;
+        match event::read()?.into() {
+            Input {
+                key: Key::Enter, ..
+            } => {}
+            Input { key: Key::Esc, .. } => break Ok(()),
+            Input { key: Key::Up, .. } => reset_preset(&mut textarea, &mut preset_index, -1),
+            Input { key: Key::Down, .. } => reset_preset(&mut textarea, &mut preset_index, 1),
+            input => {
+                textarea.input(input);
+            }
+        }
+    }
+}
+
+fn reset_preset(textarea: &mut TextArea<'_>, preset_index: &mut usize, offset: isize) {
+    *preset_index = preset_index
+        .saturating_add_signed(offset)
+        .min(PRESET_FILTERS.len() - 1);
+    let input = PRESET_FILTERS[*preset_index];
+    textarea.select_all();
+    textarea.delete_line_by_head();
+    textarea.insert_str(input);
+}
+
+fn render(frame: &mut Frame, textarea: &TextArea) {
+    let layout = Layout::vertical([Constraint::Length(3), Constraint::Fill(1)]);
+    let [top, body] = layout.areas(frame.area());
+    frame.render_widget(textarea, top);
+    let filter = textarea.lines()[0].to_string();
+
+    let Ok(env_filter) = tracing_subscriber::EnvFilter::builder().parse(filter) else {
+        let text = Text::from("Error parsing filter");
+        frame.render_widget(text, body);
+        return;
+    };
+    let writer = StringWriter::default();
+    let collector = tracing_subscriber::fmt()
+        .with_env_filter(env_filter)
+        .with_writer(writer.clone())
+        .finish();
+
+    tracing::collect::with_default(collector, simulate_logging);
+    let output = writer.to_string();
+    let text = output
+        .into_text()
+        .unwrap_or(Text::from("Error parsing output"));
+    frame.render_widget(text, body);
+}
+
+#[tracing::instrument]
+fn simulate_logging() {
+    tracing::info!("This is an info message");
+    tracing::error!("This is an error message");
+    tracing::warn!("This is a warning message");
+    tracing::debug!("This is a debug message");
+    tracing::trace!("This is a trace message");
+
+    other_crate();
+    trace_span();
+    with_fields(42, "bar");
+    with_fields(99, "nope");
+}
+
+#[tracing::instrument(target = "other_crate")]
+fn other_crate() {
+    tracing::error!(
+        target: "other_crate",
+        "This is an error message from another crate"
+    );
+    tracing::warn!(
+        target: "other_crate",
+        "This is a warning message from another crate"
+    );
+    tracing::info!(
+        target: "other_crate",
+        "This is an info message from another crate"
+    );
+    tracing::debug!(
+        target: "other_crate",
+        "This is a debug message from another crate"
+    );
+    tracing::trace!(
+        target: "other_crate",
+        "This is a trace message from another crate"
+    );
+}
+
+#[tracing::instrument]
+fn with_fields(foo: u32, bar: &'static str) {
+    tracing::info!(foo, bar, "This is an info message with fields");
+}
+
+#[tracing::instrument(level = "trace")]
+fn trace_span() {
+    tracing::error!("Error message inside a span with trace level");
+    tracing::info!("Info message inside a span with trace level");
+    tracing::trace!("Trace message inside a span with trace level");
+}
+
+#[derive(Clone, Default, Debug)]
+struct StringWriter {
+    buffer: Arc<Mutex<Vec<u8>>>,
+}
+
+impl fmt::Display for StringWriter {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let buffer = self.buffer.lock().unwrap();
+        let string = String::from_utf8_lossy(&buffer);
+        write!(f, "{}", string)
+    }
+}
+
+impl io::Write for StringWriter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.buffer.lock().unwrap().write(buf)
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        self.buffer.lock().unwrap().flush()
+    }
+}
+
+impl<'a> MakeWriter<'a> for StringWriter {
+    type Writer = Self;
+
+    fn make_writer(&'a self) -> Self::Writer {
+        self.clone()
+    }
+}