Implement Default for formatters and Facility; get hostname autom…

…atically.

Cargo.toml

@@ -10,6 +10,7 @@ documentation = "https://docs.rs/syslog"
 keywords = ["syslog", "logs", "logging"]
 
 [dependencies]
+hostname    = "^0.3"
 libc        = "^0.2"
 time        = "^0.1"
 log         = { version =  "^0.4", features = [ "std" ] }

src/facility.rs

@@ -54,3 +54,12 @@ impl FromStr for Facility {
         Ok(result)
     }
 }
+
+impl Default for Facility {
+    /// Returns the default `Facility`, which is `LOG_USER` (as [specified by POSIX]).
+    /// 
+    /// [specified by POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/closelog.html
+    fn default() -> Self {
+        Facility::LOG_USER
+    }
+}

src/format.rs

@@ -6,6 +6,8 @@ use std::collections::HashMap;
 use Priority;
 use errors::*;
 use facility::Facility;
+use get_hostname;
+use get_process_info;
 
 #[allow(non_camel_case_types)]
 #[derive(Copy,Clone)]
@@ -80,6 +82,33 @@ impl<T: Display> LogFormat<T> for Formatter3164 {
   }
 }
 
+impl Default for Formatter3164 {
+  /// Returns a `Formatter3164` with default settings.
+  /// 
+  /// The default settings are as follows:
+  /// 
+  /// * `facility`: `LOG_USER`, as [specified by POSIX].
+  /// * `hostname`: Automatically detected using [the `hostname` crate], if possible.
+  /// * `process`: Automatically detected using [`std::env::current_exe`], or if that fails, an empty string.
+  /// * `pid`: Automatically detected using [`libc::getpid`].
+  /// 
+  /// [`libc::getpid`]: https://docs.rs/libc/0.2/libc/fn.getpid.html
+  /// [specified by POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/closelog.html
+  /// [`std::env::current_exe`]: https://doc.rust-lang.org/std/env/fn.current_exe.html
+  /// [the `hostname` crate]: https://crates.io/crates/hostname
+  fn default() -> Self {
+    let (process, pid) = get_process_info().unwrap_or((String::new(), unsafe { libc::getpid() }));
+    let hostname = get_hostname().ok();
+
+    Self {
+      facility: Default::default(),
+      hostname,
+      process,
+      pid,
+    }
+  }
+}
+
 /// RFC 5424 structured data
 pub type StructuredData = HashMap<String, HashMap<String, String>>;
 
@@ -124,6 +153,67 @@ impl<T: Display> LogFormat<(i32, StructuredData, T)> for Formatter5424 {
   }
 }
 
+impl Default for Formatter5424 {
+  /// Returns a `Formatter5424` with default settings.
+  /// 
+  /// The default settings are as follows:
+  /// 
+  /// * `facility`: `LOG_USER`, as [specified by POSIX].
+  /// * `hostname`: Automatically detected using [the `hostname` crate], if possible.
+  /// * `process`: Automatically detected using [`std::env::current_exe`], or if that fails, an empty string.
+  /// * `pid`: Automatically detected using [`libc::getpid`].
+  /// 
+  /// [`libc::getpid`]: https://docs.rs/libc/0.2/libc/fn.getpid.html
+  /// [specified by POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/closelog.html
+  /// [`std::env::current_exe`]: https://doc.rust-lang.org/std/env/fn.current_exe.html
+  /// [the `hostname` crate]: https://crates.io/crates/hostname
+  fn default() -> Self {
+    // Get the defaults from `Formatter3164` and move them over.
+    let Formatter3164 { facility, hostname, process, pid } = Default::default();
+    Self { facility, hostname, process, pid }
+  }
+}
+
 fn encode_priority(severity: Severity, facility: Facility) -> Priority {
   facility as u8 | severity as u8
 }
+
+#[test]
+fn test_formatter3164_defaults() {
+  let d = Formatter3164::default();
+
+  // `Facility` doesn't implement `PartialEq`, so we use a `match` instead.
+  assert!(match d.facility {
+    Facility::LOG_USER => true,
+    _ => false
+  });
+
+  assert!(match &d.hostname {
+    Some(hostname) => !hostname.is_empty(),
+    None => false,
+  });
+
+  assert!(!d.process.is_empty());
+
+  // Can't really make any assertions about the pid.
+}
+
+#[test]
+fn test_formatter5424_defaults() {
+  let d = Formatter5424::default();
+
+  // `Facility` doesn't implement `PartialEq`, so we use a `match` instead.
+  assert!(match d.facility {
+    Facility::LOG_USER => true,
+    _ => false
+  });
+
+  assert!(match &d.hostname {
+    Some(hostname) => !hostname.is_empty(),
+    None => false,
+  });
+
+  assert!(!d.process.is_empty());
+
+  // Can't really make any assertions about the pid.
+}

src/lib.rs

@@ -434,7 +434,7 @@ pub fn init(facility: Facility, log_level: log::LevelFilter,
   let process = application_name.map(From::from).unwrap_or(process_name);
   let formatter = Formatter3164 {
     facility,
-    hostname: None,
+    hostname: get_hostname().ok(),
     process,
     pid,
   };
@@ -469,3 +469,6 @@ fn get_process_info() -> Result<(String,i32)> {
   })
 }
 
+fn get_hostname() -> Result<String> {
+  Ok(hostname::get()?.to_string_lossy().to_string())
+}