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a2a8927a XL |
1 | //! This crate allows tools to enable rust logging without having to magically |
2 | //! match rustc's tracing crate version. | |
3 | //! | |
4 | //! For example if someone is working on rustc_ast and wants to write some | |
5 | //! minimal code against it to run in a debugger, with access to the `debug!` | |
6 | //! logs emitted by rustc_ast, that can be done by writing: | |
7 | //! | |
8 | //! ```toml | |
9 | //! [dependencies] | |
10 | //! rustc_ast = { path = "../rust/compiler/rustc_ast" } | |
11 | //! rustc_log = { path = "../rust/compiler/rustc_log" } | |
12 | //! rustc_span = { path = "../rust/compiler/rustc_span" } | |
13 | //! ``` | |
14 | //! | |
15 | //! ``` | |
16 | //! fn main() { | |
17 | //! rustc_log::init_rustc_env_logger().unwrap(); | |
18 | //! | |
19 | //! let edition = rustc_span::edition::Edition::Edition2021; | |
20 | //! rustc_span::create_session_globals_then(edition, || { | |
21 | //! /* ... */ | |
22 | //! }); | |
23 | //! } | |
24 | //! ``` | |
25 | //! | |
26 | //! Now `RUSTC_LOG=debug cargo run` will run your minimal main.rs and show | |
27 | //! rustc's debug logging. In a workflow like this, one might also add | |
28 | //! `std::env::set_var("RUSTC_LOG", "debug")` to the top of main so that `cargo | |
29 | //! run` by itself is sufficient to get logs. | |
30 | //! | |
31 | //! The reason rustc_log is a tiny separate crate, as opposed to exposing the | |
32 | //! same things in rustc_driver only, is to enable the above workflow. If you | |
33 | //! had to depend on rustc_driver in order to turn on rustc's debug logs, that's | |
34 | //! an enormously bigger dependency tree; every change you make to rustc_ast (or | |
35 | //! whichever piece of the compiler you are interested in) would involve | |
36 | //! rebuilding all the rest of rustc up to rustc_driver in order to run your | |
37 | //! main.rs. Whereas by depending only on rustc_log and the few crates you are | |
38 | //! debugging, you can make changes inside those crates and quickly run main.rs | |
39 | //! to read the debug logs. | |
40 | ||
f2b60f7d FG |
41 | #![deny(rustc::untranslatable_diagnostic)] |
42 | #![deny(rustc::diagnostic_outside_of_impl)] | |
43 | ||
a2a8927a XL |
44 | use std::env::{self, VarError}; |
45 | use std::fmt::{self, Display}; | |
46 | use std::io; | |
47 | use tracing_subscriber::filter::{Directive, EnvFilter, LevelFilter}; | |
48 | use tracing_subscriber::layer::SubscriberExt; | |
49 | ||
50 | pub fn init_rustc_env_logger() -> Result<(), Error> { | |
51 | init_env_logger("RUSTC_LOG") | |
52 | } | |
53 | ||
54 | /// In contrast to `init_rustc_env_logger` this allows you to choose an env var | |
55 | /// other than `RUSTC_LOG`. | |
56 | pub fn init_env_logger(env: &str) -> Result<(), Error> { | |
57 | let filter = match env::var(env) { | |
58 | Ok(env) => EnvFilter::new(env), | |
59 | _ => EnvFilter::default().add_directive(Directive::from(LevelFilter::WARN)), | |
60 | }; | |
61 | ||
62 | let color_logs = match env::var(String::from(env) + "_COLOR") { | |
63 | Ok(value) => match value.as_ref() { | |
64 | "always" => true, | |
65 | "never" => false, | |
66 | "auto" => stderr_isatty(), | |
67 | _ => return Err(Error::InvalidColorValue(value)), | |
68 | }, | |
69 | Err(VarError::NotPresent) => stderr_isatty(), | |
70 | Err(VarError::NotUnicode(_value)) => return Err(Error::NonUnicodeColorValue), | |
71 | }; | |
72 | ||
04454e1e FG |
73 | let verbose_entry_exit = match env::var_os(String::from(env) + "_ENTRY_EXIT") { |
74 | None => false, | |
923072b8 | 75 | Some(v) => &v != "0", |
04454e1e FG |
76 | }; |
77 | ||
a2a8927a XL |
78 | let layer = tracing_tree::HierarchicalLayer::default() |
79 | .with_writer(io::stderr) | |
80 | .with_indent_lines(true) | |
81 | .with_ansi(color_logs) | |
82 | .with_targets(true) | |
04454e1e FG |
83 | .with_verbose_exit(verbose_entry_exit) |
84 | .with_verbose_entry(verbose_entry_exit) | |
a2a8927a XL |
85 | .with_indent_amount(2); |
86 | #[cfg(parallel_compiler)] | |
87 | let layer = layer.with_thread_ids(true).with_thread_names(true); | |
88 | ||
89 | let subscriber = tracing_subscriber::Registry::default().with(filter).with(layer); | |
90 | tracing::subscriber::set_global_default(subscriber).unwrap(); | |
91 | ||
92 | Ok(()) | |
93 | } | |
94 | ||
95 | pub fn stdout_isatty() -> bool { | |
96 | atty::is(atty::Stream::Stdout) | |
97 | } | |
98 | ||
99 | pub fn stderr_isatty() -> bool { | |
100 | atty::is(atty::Stream::Stderr) | |
101 | } | |
102 | ||
103 | #[derive(Debug)] | |
104 | pub enum Error { | |
105 | InvalidColorValue(String), | |
106 | NonUnicodeColorValue, | |
107 | } | |
108 | ||
109 | impl std::error::Error for Error {} | |
110 | ||
111 | impl Display for Error { | |
112 | fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { | |
113 | match self { | |
114 | Error::InvalidColorValue(value) => write!( | |
115 | formatter, | |
116 | "invalid log color value '{}': expected one of always, never, or auto", | |
117 | value, | |
118 | ), | |
119 | Error::NonUnicodeColorValue => write!( | |
120 | formatter, | |
121 | "non-Unicode log color value: expected one of always, never, or auto", | |
122 | ), | |
123 | } | |
124 | } | |
125 | } |