Add syslog v7 support

A while back the syslog crate was updated to v7.
This PR adds compatibility with this new version in fern.

Also added `.vscode` to the `.gitignore` and fixed a comment where it mentioned `syslog-4` where it should have been `syslog-6`

Signed-off-by: BlackDex <black.dex@gmail.com>

.github/workflows/rust.yml

@@ -59,6 +59,10 @@ jobs:
         with:
           command: test
           args: --features=syslog-6
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+          args: --features=syslog-7
       - uses: actions-rs/cargo@v1
         with:
           command: test
@@ -103,6 +107,7 @@ jobs:
       - run: cargo run --example syslog3 --features syslog-3
       - run: cargo run --example syslog4 --features syslog-4
       - run: cargo run --example syslog --features syslog-6
+      - run: cargo run --example syslog7 --features syslog-7
   msrv:
     name: MSRV Compatability - fern
     runs-on: ${{ matrix.os }}
@@ -169,6 +174,22 @@ jobs:
           toolchain: 1.67.0
           override: true
       - run: cargo build --features syslog-6
+  msrv_syslog_7:
+    name: MSRV Compatability - fern/syslog-7
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - windows-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: 1.67.0
+          override: true
+      - run: cargo build --features syslog-7
   fmt_and_clippy:
     name: Optional Lints
     runs-on: ubuntu-latest

.gitignore

@@ -42,3 +42,4 @@ nb-configuration.xml
 *.iws
 *.sublime-project
 *.sublime-workspace
+.vscode

Cargo.toml

@@ -27,6 +27,7 @@ chrono = { version = "0.4", default-features = false, features = ["std", "clock"
 syslog3 = { version = "3", package = "syslog", optional = true }
 syslog4 = { version = "4", package = "syslog", optional = true }
 syslog6 = { version = "6", package = "syslog", optional = true }
+syslog7 = { version = "7", package = "syslog", optional = true }
 reopen1 = { version = "~1", package = "reopen", features = ["signals"], optional = true }
 reopen03 = { version = "^0.3", package = "reopen", optional = true }
 libc = { version = "0.2.58", optional = true }
@@ -35,11 +36,14 @@ libc = { version = "0.2.58", optional = true }
 syslog-3 = ["syslog3"]
 syslog-4 = ["syslog4"]
 syslog-6 = ["syslog6"]
+syslog-7 = ["syslog7"]
 reopen-03 = ["reopen03", "libc"]
 reopen-1 = ["reopen1", "libc"]
 meta-logging-in-format = []
 date-based = ["chrono"]
 
+# default = ["syslog-7"]
+
 [dev-dependencies]
 tempfile = "3"
 clap = "2.22"
@@ -60,6 +64,10 @@ required-features = ["colored"]
 name = "pretty-colored"
 required-features = ["colored"]
 
+[[example]]
+name = "syslog7"
+required-features = ["syslog-7"]
+
 [[example]]
 name = "syslog"
 required-features = ["syslog-6"]

examples/syslog7.rs

@@ -0,0 +1,54 @@
+#[cfg(not(windows))]
+// This is necessary because `fern` depends on both version 3, 4 and 6
+use syslog7 as syslog;
+
+#[cfg(not(windows))]
+use log::{debug, info, warn};
+
+#[cfg(not(windows))]
+fn setup_logging() -> Result<(), Box<dyn std::error::Error>> {
+    let syslog_fmt = syslog::Formatter3164 {
+        facility: syslog::Facility::LOG_USER,
+        hostname: None,
+        process: "fern-syslog-example".into(),
+        pid: 0,
+    };
+    fern::Dispatch::new()
+        // by default only accept warning messages so as not to spam
+        .level(log::LevelFilter::Warn)
+        // but accept Info if we explicitly mention it
+        .level_for("explicit-syslog", log::LevelFilter::Info)
+        .chain(syslog::unix(syslog_fmt)?)
+        .apply()?;
+
+    Ok(())
+}
+
+#[cfg(not(windows))]
+fn main() {
+    setup_logging().expect("failed to initialize logging.");
+
+    // None of this will be shown in the syslog:
+    for i in 0..5 {
+        info!("executing section: {}", i);
+
+        debug!("section {} 1/4 complete.", i);
+
+        debug!("section {} 1/2 complete.", i);
+
+        debug!("section {} 3/4 complete.", i);
+
+        info!("section {} completed!", i);
+    }
+
+    // these two *will* show.
+
+    info!(target: "explicit-syslog", "hello to the syslog! this is rust.");
+
+    warn!("AHHH something's on fire.");
+}
+
+#[cfg(windows)]
+fn main() {
+    panic!("this example does not work on Windows.");
+}

src/builders.rs

@@ -11,6 +11,9 @@ use std::path::{Path, PathBuf};
 #[cfg(all(not(windows), any(feature = "syslog-4", feature = "syslog-6")))]
 use std::collections::HashMap;
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+use std::collections::BTreeMap;
+
 use log::Log;
 
 use crate::{log_impl, Filter, FormatCallback, Formatter};
@@ -24,6 +27,9 @@ use crate::{Syslog4Rfc3164Logger, Syslog4Rfc5424Logger, Syslog4TransformFn};
 #[cfg(all(not(windows), feature = "syslog-6"))]
 use crate::{Syslog6Rfc3164Logger, Syslog6Rfc5424Logger, Syslog6TransformFn};
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+use crate::{Syslog7Rfc3164Logger, Syslog7Rfc5424Logger, Syslog7TransformFn};
+
 /// The base dispatch logger.
 ///
 /// This allows for formatting log records, limiting what records can be passed
@@ -504,6 +510,21 @@ impl Dispatch {
                         transform,
                     }))
                 }
+                #[cfg(all(not(windows), feature = "syslog-7"))]
+                OutputInner::Syslog7Rfc3164(logger) => {
+                    max_child_level = log::LevelFilter::Trace;
+                    Some(log_impl::Output::Syslog7Rfc3164(log_impl::Syslog7Rfc3164 {
+                        inner: Mutex::new(logger),
+                    }))
+                }
+                #[cfg(all(not(windows), feature = "syslog-7"))]
+                OutputInner::Syslog7Rfc5424 { logger, transform } => {
+                    max_child_level = log::LevelFilter::Trace;
+                    Some(log_impl::Output::Syslog7Rfc5424(log_impl::Syslog7Rfc5424 {
+                        inner: Mutex::new(logger),
+                        transform,
+                    }))
+                }
                 OutputInner::Panic => {
                     max_child_level = log::LevelFilter::Trace;
                     Some(log_impl::Output::Panic(log_impl::Panic))
@@ -706,6 +727,14 @@ enum OutputInner {
         logger: Syslog6Rfc5424Logger,
         transform: Box<Syslog6TransformFn>,
     },
+    #[cfg(all(not(windows), feature = "syslog-7"))]
+    Syslog7Rfc3164(Syslog7Rfc3164Logger),
+    /// Sends all messages through the transform then passes to the syslog.
+    #[cfg(all(not(windows), feature = "syslog-7"))]
+    Syslog7Rfc5424 {
+        logger: Syslog7Rfc5424Logger,
+        transform: Box<Syslog7TransformFn>,
+    },
     /// Panics with messages text for all messages.
     Panic,
     /// File logger with custom date and timestamp suffix in file name.
@@ -939,12 +968,31 @@ impl From<Syslog6Rfc3164Logger> for Output {
     /// This is for RFC 3164 loggers. To use an RFC 5424 logger, use the
     /// [`Output::syslog_5424`] helper method.
     ///
-    /// This requires the `"syslog-4"` feature.
+    /// This requires the `"syslog-6"` feature.
     fn from(log: Syslog6Rfc3164Logger) -> Self {
         Output(OutputInner::Syslog6Rfc3164(log))
     }
 }
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+impl From<Syslog7Rfc3164Logger> for Output {
+    /// Creates an output logger which writes all messages to the given syslog.
+    ///
+    /// Log levels are translated trace => debug, debug => debug, info =>
+    /// informational, warn => warning, and error => error.
+    ///
+    /// Note that due to <https://github.com/Geal/rust-syslog/issues/41>,
+    /// logging to this backend requires one allocation per log call.
+    ///
+    /// This is for RFC 3164 loggers. To use an RFC 5424 logger, use the
+    /// [`Output::syslog_5424`] helper method.
+    ///
+    /// This requires the `"syslog-7"` feature.
+    fn from(log: Syslog7Rfc3164Logger) -> Self {
+        Output(OutputInner::Syslog7Rfc3164(log))
+    }
+}
+
 impl From<Panic> for Output {
     /// Creates an output logger which will panic with message text for all
     /// messages.
@@ -1249,6 +1297,34 @@ impl Output {
         })
     }
 
+    /// Returns a logger which logs into an RFC5424 syslog (using syslog version 6)
+    ///
+    /// This method takes an additional transform method to turn the log data
+    /// into RFC5424 data.
+    ///
+    /// I've honestly got no clue what the expected keys and values are for
+    /// this kind of logging, so I'm just going to link [the rfc] instead.
+    ///
+    /// If you're an expert on syslog logging and would like to contribute
+    /// an example to put here, it would be gladly accepted!
+    ///
+    /// This requires the `"syslog-7"` feature.
+    ///
+    /// [the rfc]: https://tools.ietf.org/html/rfc5424
+    #[cfg(all(not(windows), feature = "syslog-7"))]
+    pub fn syslog7_5424<F>(logger: Syslog7Rfc5424Logger, transform: F) -> Self
+    where
+        F: Fn(&log::Record) -> (u32, BTreeMap<String, BTreeMap<String, String>>, String)
+            + Sync
+            + Send
+            + 'static,
+    {
+        Output(OutputInner::Syslog7Rfc5424 {
+            logger,
+            transform: Box::new(transform),
+        })
+    }
+
     /// Returns a logger which simply calls the given function with each
     /// message.
     ///
@@ -1407,6 +1483,16 @@ impl fmt::Debug for OutputInner {
                 .debug_tuple("Output::Syslog6Rfc5424")
                 .field(&"<unprintable syslog::Logger>")
                 .finish(),
+            #[cfg(all(not(windows), feature = "syslog-7"))]
+            OutputInner::Syslog7Rfc3164 { .. } => f
+                .debug_tuple("Output::Syslog7Rfc3164")
+                .field(&"<unprintable syslog::Logger>")
+                .finish(),
+            #[cfg(all(not(windows), feature = "syslog-7"))]
+            OutputInner::Syslog7Rfc5424 { .. } => f
+                .debug_tuple("Output::Syslog7Rfc5424")
+                .field(&"<unprintable syslog::Logger>")
+                .finish(),
             OutputInner::Dispatch(ref dispatch) => {
                 f.debug_tuple("Output::Dispatch").field(dispatch).finish()
             }

src/lib.rs

@@ -238,6 +238,9 @@ use std::{
 #[cfg(all(not(windows), any(feature = "syslog-4", feature = "syslog-6")))]
 use std::collections::HashMap;
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+use std::collections::BTreeMap;
+
 pub use crate::{
     builders::{Dispatch, Output, Panic},
     errors::InitError,
@@ -291,6 +294,12 @@ type Syslog6Rfc3164Logger = syslog6::Logger<syslog6::LoggerBackend, syslog6::For
 #[cfg(all(not(windows), feature = "syslog-6"))]
 type Syslog6Rfc5424Logger = syslog6::Logger<syslog6::LoggerBackend, syslog6::Formatter5424>;
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+type Syslog7Rfc3164Logger = syslog7::Logger<syslog7::LoggerBackend, syslog7::Formatter3164>;
+
+#[cfg(all(not(windows), feature = "syslog-7"))]
+type Syslog7Rfc5424Logger = syslog7::Logger<syslog7::LoggerBackend, syslog7::Formatter5424>;
+
 #[cfg(all(not(windows), feature = "syslog-4"))]
 type Syslog4TransformFn =
     dyn Fn(&log::Record) -> (i32, HashMap<String, HashMap<String, String>>, String) + Send + Sync;
@@ -299,6 +308,10 @@ type Syslog4TransformFn =
 type Syslog6TransformFn =
     dyn Fn(&log::Record) -> (u32, HashMap<String, HashMap<String, String>>, String) + Send + Sync;
 
+#[cfg(all(not(windows), feature = "syslog-7"))]
+type Syslog7TransformFn =
+    dyn Fn(&log::Record) -> (u32, BTreeMap<String, BTreeMap<String, String>>, String) + Send + Sync;
+
 /// Convenience method for opening a log file with common options.
 ///
 /// Equivalent to: