Fix #15, don't panic on closed pipes

Logging will now use stderr instead of stdout.

config.toml

@@ -9,7 +9,7 @@
 # If omitted, `$XDG_CONFIG_HOME/mensa/config.toml` or
 #             `$HOME/.config/mensa/config.toml` (if $XDG_CONFIG_HOME is unset)
 # are checked.
-# 
+#
 # All options can also be specified on the command line or in the environment
 #  1) CLI flags take precedence over
 #  2) ENVIRONMENT VARIABLES, which overwrite

src/cache/dummy.rs

@@ -38,10 +38,6 @@ impl Cache for DummyCache {
         let entry = read
             .get(&path)
             .expect("BUG: Metadata exists, but entry does not!");
-        eprintln!(
-            "Cache read for {:?}\n-> Returning: {:#?}",
-            meta.integrity, entry.text
-        );
         Ok(entry.text.clone())
     }
 
@@ -56,10 +52,6 @@ impl Cache for DummyCache {
                 text: text.to_owned(),
             },
         );
-        eprintln!(
-            "Cache write to {:?}\n-> Headers: {:#?}\n-> Content: {:#?}",
-            url, headers, text
-        );
         Ok(())
     }
 
@@ -67,7 +59,6 @@ impl Cache for DummyCache {
         let hash = path_from_key(url);
         let read = self.content.read().expect("Reading cache failed");
         let entry = read.get(&hash);
-        eprintln!("Cache Metadata for {:?}: {:?}", url, entry);
         match entry {
             Some(entry) => Ok(Some(clone_metadata(&entry.meta))),
             None => Ok(None),
@@ -76,7 +67,6 @@ impl Cache for DummyCache {
 
     fn clear(&self) -> Result<()> {
         self.content.write().expect("Writing cache failed").clear();
-        eprintln!("Cache cleared");
         Ok(())
     }
 
@@ -92,9 +82,7 @@ impl Cache for DummyCache {
 
 fn path_from_key(key: &str) -> String {
     let integrity = Integrity::from(key);
-    let path = path_from_integrity(&integrity);
+    path_from_integrity(&integrity)
-    eprintln!("Hashing key {:?} -> {:#?}", key, path);
-    path
 }
 
 fn path_from_integrity(integrity: &Integrity) -> String {
@@ -102,7 +90,6 @@ fn path_from_integrity(integrity: &Integrity) -> String {
     let (algorithm, digest) = integrity.to_hex();
     path += &algorithm.to_string();
     path += &digest;
-    eprintln!("Hashing integrity {:?} -> {:#?}", integrity, path);
     path
 }
 

src/cache/tests.rs

@@ -14,7 +14,7 @@ fn print_cache_list(header: &'static str) -> Result<()> {
     CACHE.list()?.iter().for_each(|meta| {
         let age_ms = meta.time;
         let cache_age = chrono::Utc.timestamp((age_ms / 1000) as i64, (age_ms % 1000) as u32);
-        eprintln!(
+        println!(
             "| - {}\n|   SIZE: {}\n|   AGE: {}",
             meta.key, meta.size, cache_age
         )

src/canteen/mod.rs

@@ -99,13 +99,12 @@ impl Canteen {
                 .initial_indent(ADRESS_INDENT)
                 .subsequent_indent(ADRESS_INDENT),
         );
-        println!(
+        try_println!(
             "{} {}\n{}",
             color!(format!("{:>4}", self.id); bold, bright_yellow),
             color!(self.meta()?.name; bold),
             color!(address; bright_black),
-        );
+        )
-        Ok(())
     }
 
     pub fn id(&self) -> CanteenId {
@@ -132,7 +131,7 @@ impl Canteen {
             Self::print_all_json(canteens)
         } else {
             for canteen in canteens {
-                println!();
+                try_println!()?;
                 canteen.print()?;
             }
             Ok(())

src/main.rs

@@ -57,7 +57,7 @@
 //!
 //! ### Examples
 //!
-//! #### 
+//! ####
 //! <details>
 //!   <summary><b>Meals on monday</b> (<i>Click me!</i>)</summary>
 //!
@@ -70,7 +70,7 @@
 //!    ┊
 //!    ┊ ╭───╴Bohnengemüse
 //!    ┊ ├─╴Gemüsebeilage 🌱
-//!    ┊ ╰╴( 0.55€ )  
+//!    ┊ ╰╴( 0.55€ )
 //!    ...
 //!   ```
 //! </details>
@@ -95,13 +95,13 @@
 //!
 //!   ```console
 //!   $ mensa tags
-//!   
+//!
 //!      0 Acidifier
 //!        Contains artificial acidifier
-//!   
+//!
 //!      1 Alcohol
 //!        Contains alcohol
-//!   
+//!
 //!      2 Antioxidant
 //!        Contains an antioxidant
 //!     ...
@@ -113,7 +113,7 @@
 //!
 //!   ```console
 //!   $ mensa meals close --date sun
-//!   
+//!
 //!    Leipzig, Cafeteria Dittrichring
 //!    ┊
 //!    ┊ ╭───╴Vegetarisch gefüllte Zucchini
@@ -121,7 +121,7 @@
 //!    ┊ ├╴Rucola-Kartoffelpüree
 //!    ┊ ├╴Tomaten-Ratatouille-Soße
 //!    ┊ ╰╴( 2.65€ )  2 11 12 19
-//!   
+//!
 //!    Leipzig, Mensa am Park
 //!    ┊
 //!    ┊ ╭───╴Apfelrotkohl
@@ -147,12 +147,14 @@
 //! - `$HOME/Library/Application Support/mensa/config.toml` on **macOS**,
 //! - `{FOLDERID_RoamingAppData}\mensa\config.toml` on **Windows**
 
+use std::io;
+
 use cache::Cache;
 use chrono::Duration;
 use directories_next::ProjectDirs;
 use lazy_static::lazy_static;
 use serde::Serialize;
-use tracing::error;
+use tracing::{error, info};
 
 /// Colorizes the output.
 ///
@@ -211,6 +213,18 @@ macro_rules! if_plain {
     };
 }
 
+/// Safer `println` which doesn't panic, but errors.
+macro_rules! try_println {
+    () => {
+        try_println!("\n")
+    };
+    ($str:literal $(, $args:expr )* $(,)?) => ({
+        use std::io::Write;
+        writeln!(::std::io::stdout(), $str, $( $args ),* )
+            .map_err(|why| crate::error::Error::Io(why, "printing"))
+    })
+}
+
 mod cache;
 mod canteen;
 mod config;
@@ -240,17 +254,25 @@ lazy_static! {
 }
 
 fn main() -> Result<()> {
-    let res = real_main();
+    match real_main() {
-    match res {
+        Ok(_) => Ok(()),
-        Ok(_) => {}
+        // Ignore broken pipe errors, but log them
-        Err(ref why) => error!("{}", why),
+        Err(Error::Io(err, _)) if err.kind() == io::ErrorKind::BrokenPipe => {
+            info!("Pipe was closed");
+            Ok(())
+        }
+        Err(why) => {
+            error!("{}", why);
+            Err(why)
+        }
     }
-    res
 }
 
 fn real_main() -> Result<()> {
     // Initialize logger
-    tracing_subscriber::fmt::init();
+    tracing_subscriber::FmtSubscriber::builder()
+        .with_writer(::std::io::stderr)
+        .init();
     // Clear cache if requested
     if CONF.args.clear_cache {
         CACHE.clear()?;

src/meal/complete.rs

@@ -5,7 +5,7 @@ use lazy_static::lazy_static;
 use serde::Serialize;
 use unicode_width::UnicodeWidthStr;
 
-use crate::get_sane_terminal_dimensions;
+use crate::{error::Result, get_sane_terminal_dimensions};
 
 use super::{MealId, Meta, PRE};
 
@@ -27,39 +27,40 @@ pub struct MealComplete<'c> {
 
 impl<'c> MealComplete<'c> {
     /// Print this [`MealComplete`] to the terminal.
-    pub fn print(&self, highlight: bool) {
+    pub fn print(&self, highlight: bool) -> Result<()> {
         let (width, _height) = get_sane_terminal_dimensions();
         // Print meal name
-        self.print_name_to_terminal(width, highlight);
+        self.print_name_to_terminal(width, highlight)?;
         // Get notes, i.e. allergenes, descriptions, tags
-        self.print_category_and_primary_tags(highlight);
+        self.print_category_and_primary_tags(highlight)?;
-        self.print_descriptions(width, highlight);
+        self.print_descriptions(width, highlight)?;
-        self.print_price_and_secondary_tags(highlight);
+        self.print_price_and_secondary_tags(highlight)
     }
 
-    fn print_name_to_terminal(&self, width: usize, highlight: bool) {
+    fn print_name_to_terminal(&self, width: usize, highlight: bool) -> Result<()> {
         let max_name_width = width - NAME_PRE.width() - PRE.width();
         let mut name_parts = textwrap::wrap(&self.meta.name, max_name_width).into_iter();
         // There will always be a first part of the splitted string
         let first_name_part = name_parts.next().unwrap();
-        println!(
+        try_println!(
             "{}{}{}",
             *PRE,
             hl_if(highlight, *NAME_PRE),
             color!(hl_if(highlight, first_name_part); bold),
-        );
+        )?;
         for name_part in name_parts {
             let name_part = hl_if(highlight, name_part);
-            println!(
+            try_println!(
                 "{}{}{}",
                 *PRE,
                 hl_if(highlight, *NAME_CONTINUE_PRE),
                 color!(name_part; bold),
-            );
+            )?;
         }
+        Ok(())
     }
 
-    fn print_category_and_primary_tags(&self, highlight: bool) {
+    fn print_category_and_primary_tags(&self, highlight: bool) -> Result<()> {
         let mut tag_str = self
             .meta
             .tags
@@ -69,39 +70,40 @@ impl<'c> MealComplete<'c> {
         let tag_str_colored =
             if_plain!(color!(tag_str.join(" "); bright_black), tag_str.join(", "));
         let comma_if_plain = if_plain!("", ",");
-        println!(
+        try_println!(
             "{}{}{}{} {}",
             *PRE,
             hl_if(highlight, *CATEGORY_PRE),
             color!(self.meta.category; bright_blue),
             color!(comma_if_plain; bright_black),
             tag_str_colored
-        );
+        )
     }
 
-    fn print_descriptions(&self, width: usize, highlight: bool) {
+    fn print_descriptions(&self, width: usize, highlight: bool) -> Result<()> {
         let max_note_width = width - OTHER_NOTE_PRE.width() - PRE.width();
         for note in &self.meta.descs {
             let mut note_parts = textwrap::wrap(note, max_note_width).into_iter();
             // There will always be a first part in the splitted string
-            println!(
+            try_println!(
                 "{}{}{}",
                 *PRE,
                 hl_if(highlight, *OTHER_NOTE_PRE),
                 note_parts.next().unwrap()
-            );
+            )?;
             for part in note_parts {
-                println!(
+                try_println!(
                     "{}{}{}",
                     *PRE,
                     hl_if(highlight, *OTHER_NOTE_CONTINUE_PRE),
                     part
-                );
+                )?;
             }
         }
+        Ok(())
     }
 
-    fn print_price_and_secondary_tags(&self, highlight: bool) {
+    fn print_price_and_secondary_tags(&self, highlight: bool) -> Result<()> {
         let prices = self.meta.prices.to_terminal_string();
         let mut secondary: Vec<_> = self
             .meta
@@ -111,13 +113,13 @@ impl<'c> MealComplete<'c> {
             .collect();
         secondary.sort_unstable();
         let secondary_str = secondary.iter().map(|tag| tag.as_id()).join(" ");
-        println!(
+        try_println!(
             "{}{}{}  {}",
             *PRE,
             hl_if(highlight, *PRICES_PRE),
             prices,
             color!(secondary_str; bright_black),
-        );
+        )
     }
 }
 

src/meal/mod.rs

@@ -96,7 +96,7 @@ impl Meal {
         let day = CONF.date();
         for canteen in canteens {
             let name = canteen.name()?;
-            println!("\n {}", color!(name; bright_black));
+            try_println!("\n {}", color!(name; bright_black))?;
             match canteen.meals_at_mut(day)? {
                 Some(meals) => {
                     let mut printed_at_least_one_meal = false;
@@ -104,18 +104,16 @@ impl Meal {
                         let complete = meal.complete()?;
                         if filter.is_match(&complete) {
                             let is_fav = favs.is_non_empty_match(&complete);
-                            println!("{}", *PRE);
+                            try_println!("{}", *PRE)?;
-                            complete.print(is_fav);
+                            complete.print(is_fav)?;
                             printed_at_least_one_meal = true;
                         }
                     }
                     if !printed_at_least_one_meal {
-                        println!("{} {}", *PRE, color!("no matching meals found"; dimmed));
+                        try_println!("{} {}", *PRE, color!("no matching meals found"; dimmed))?
                     }
                 }
-                None => {
+                None => try_println!("{} {}", *PRE, color!("closed"; dimmed))?,
-                    println!("{} {}", *PRE, color!("closed"; dimmed))
-                }
             }
         }
         Ok(())

src/tag.rs

@@ -212,7 +212,7 @@ impl Tag {
     /// Print this tag.
     ///
     /// Does **not** respect `--json`, use [`Self::print_all`].
-    pub fn print(&self) {
+    pub fn print(&self) -> Result<()> {
         let emoji = if CONF.args.plain && self.is_primary() {
             format!("{:>width$}", "-", width = ID_WIDTH)
         } else {
@@ -231,12 +231,12 @@ impl Tag {
                 .initial_indent(TEXT_INDENT)
                 .subsequent_indent(TEXT_INDENT),
         );
-        println!(
+        try_println!(
             "{} {}\n{}",
             color!(emoji; bright_yellow, bold),
             color!(self; bold),
             color!(description; bright_black),
-        );
+        )
     }
 
     /// Print all tags.
@@ -245,8 +245,8 @@ impl Tag {
             Self::print_all_json()
         } else {
             for tag in Tag::iter() {
-                println!();
+                try_println!()?;
-                tag.print();
+                tag.print()?;
             }
             Ok(())
         }