proxmox-log: add tracing infrastructure

Add the `proxmox_log` crate which includes the new logging infra.
Export the `init_logger` function, which creates the `tracing` logger
that includes the default subscriber and two layer.

The first layer comes from the tracing-journald crate and logs
everything that does not come from a worker-task/thread to the syslog.
The second layer filters the exact opposite and writes the logs into the
corresponding task-log file.

Reviewed-by: Lukas Wagner <l.wagner@proxmox.com>
Tested-by: Lukas Wagner <l.wagner@proxmox.com>
Signed-off-by: Gabriel Goller <g.goller@proxmox.com>

Cargo.toml

@@ -19,6 +19,7 @@ members = [
     "proxmox-io",
     "proxmox-lang",
     "proxmox-ldap",
+    "proxmox-log",
     "proxmox-login",
     "proxmox-metrics",
     "proxmox-network-api",
@@ -104,6 +105,10 @@ tokio = "1.6"
 tokio-openssl = "0.6.1"
 tokio-stream = "0.1.0"
 tower-service = "0.3.0"
+tracing = "0.1"
+tracing-journald = "0.3.0"
+tracing-log = { version = "0.1.3", default-features = false }
+tracing-subscriber = "0.3.16"
 url = "2.2"
 walkdir = "2"
 webauthn-rs = "0.3"
@@ -121,6 +126,7 @@ proxmox-http-error = { version = "0.1.0", path = "proxmox-http-error" }
 proxmox-human-byte = { version = "0.1.0", path = "proxmox-human-byte" }
 proxmox-io = { version = "1.1.0", path = "proxmox-io" }
 proxmox-lang = { version = "1.3", path = "proxmox-lang" }
+proxmox-log= { version = "0.1.0", path = "proxmox-log" }
 proxmox-login = { version = "0.1.0", path = "proxmox-login" }
 proxmox-product-config = { version = "0.2.0", path = "proxmox-product-config" }
 proxmox-config-digest = { version = "0.1.0", path = "proxmox-config-digest" }

proxmox-log/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "proxmox-log"
+version = "0.1.0"
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+description = "Logging infrastructure for proxmox"
+
+exclude.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+nix.workspace = true
+log.workspace = true
+tracing.workspace = true
+tracing-journald.workspace = true
+tracing-subscriber.workspace = true
+tracing-log = { workspace = true, features = ["std"] }
+tokio = { workspace = true, features = ["rt-multi-thread"] }
+proxmox-time.workspace = true
+proxmox-sys.workspace = true
+

proxmox-log/debian/changelog

@@ -0,0 +1,5 @@
+rust-proxmox-log (0.1.0-3) UNRELEASED; urgency=medium
+
+  * Initial release
+
+ -- Gabriel Goller <ggoller@luna.proxmox.com>  Wed, 11 Oct 2023 15:13:58 +0200

proxmox-log/debian/control

@@ -0,0 +1,52 @@
+Source: rust-proxmox-log
+Section: rust
+Priority: optional
+Build-Depends: debhelper (>= 12),
+ dh-cargo (>= 25),
+ cargo:native <!nocheck>,
+ rustc:native <!nocheck>,
+ libstd-rust-dev <!nocheck>,
+ librust-anyhow-1+default-dev <!nocheck>,
+ librust-log-0.4+default-dev (>= 0.4.17-~~) <!nocheck>,
+ librust-nix-0.26+default-dev (>= 0.26.1-~~) <!nocheck>,
+ librust-proxmox-sys-0.5+default-dev (>= 0.5.1-~~) <!nocheck>,
+ librust-proxmox-time-1+default-dev (>= 1.1.6-~~) <!nocheck>,
+ librust-tracing-journald-0.3+default-dev <!nocheck>
+ librust-tokio-1+default-dev (>= 1.6-~~) <!nocheck>,
+ librust-tokio-1+rt-multi-thread-dev (>= 1.6-~~) <!nocheck>,
+ librust-tracing-0.1+default-dev <!nocheck>,
+ librust-tracing-log-0.1-dev (>= 0.1.3-~~) <!nocheck>,
+ librust-tracing-subscriber-0.3+default-dev (>= 0.3.16-~~) <!nocheck>
+Maintainer: Proxmox Support Team <support@proxmox.com>
+Standards-Version: 4.6.2
+Vcs-Git: git://git.proxmox.com/git/proxmox.git
+Vcs-Browser: https://git.proxmox.com/?p=proxmox.git
+X-Cargo-Crate: proxmox-log
+Rules-Requires-Root: no
+
+Package: librust-proxmox-log-dev
+Architecture: any
+Multi-Arch: same
+Depends:
+ ${misc:Depends},
+ librust-anyhow-1+default-dev,
+ librust-log-0.4+default-dev (>= 0.4.17-~~),
+ librust-nix-0.26+default-dev (>= 0.26.1-~~),
+ librust-proxmox-sys-0.5+default-dev (>= 0.5.1-~~),
+ librust-proxmox-time-1+default-dev (>= 1.1.6-~~),
+ librust-tracing-journald-0.3+default-dev,
+ librust-tokio-1+default-dev (>= 1.6-~~),
+ librust-tokio-1+rt-multi-thread-dev (>= 1.6-~~),
+ librust-tracing-0.1+default-dev,
+ librust-tracing-log-0.1-dev (>= 0.1.3-~~),
+ librust-tracing-subscriber-0.3+default-dev (>= 0.3.16-~~)
+Provides:
+ librust-proxmox-log+default-dev (= ${binary:Version}),
+ librust-proxmox-log-0-dev (= ${binary:Version}),
+ librust-proxmox-log-0+default-dev (= ${binary:Version}),
+ librust-proxmox-log-0.1-dev (= ${binary:Version}),
+ librust-proxmox-log-0.1+default-dev (= ${binary:Version}),
+ librust-proxmox-log-0.1.0-dev (= ${binary:Version}),
+ librust-proxmox-log-0.1.0+default-dev (= ${binary:Version})
+Description: Logging infrastructure for proxmox - Rust source code
+ Source code for Debianized Rust crate "proxmox-log"

proxmox-log/debian/copyright

@@ -0,0 +1,18 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+
+Files:
+ *
+Copyright: 2019 - 2024 Proxmox Server Solutions GmbH <support@proxmox.com>
+License: AGPL-3.0-or-later
+ This program is free software: you can redistribute it and/or modify it under
+ the terms of the GNU Affero General Public License as published by the Free
+ Software Foundation, either version 3 of the License, or (at your option) any
+ later version.
+ .
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+ details.
+ .
+ You should have received a copy of the GNU Affero General Public License along
+ with this program. If not, see <https://www.gnu.org/licenses/>.

proxmox-log/debian/debcargo.toml

@@ -0,0 +1,7 @@
+overlay = "."
+crate_src_path = ".."
+maintainer = "Proxmox Support Team <support@proxmox.com>"
+
+[source]
+vcs_git = "git://git.proxmox.com/git/proxmox.git"
+vcs_browser = "https://git.proxmox.com/?p=proxmox.git"

proxmox-log/src/file_logger.rs

@@ -0,0 +1,151 @@
+use std::io::Write;
+
+use anyhow::Error;
+use nix::fcntl::OFlag;
+
+use proxmox_sys::fs::{atomic_open_or_create_file, CreateOptions};
+
+/// Options to control the behavior of a [FileLogger] instance
+#[derive(Default)]
+pub struct FileLogOptions {
+    /// Open underlying log file in append mode, useful when multiple concurrent processes
+    /// want to log to the same file (e.g., HTTP access log). Note that it is only atomic
+    /// for writes smaller than the PIPE_BUF (4k on Linux).
+    /// Inside the same process you may need to still use an mutex, for shared access.
+    pub append: bool,
+    /// Open underlying log file as readable
+    pub read: bool,
+    /// If set, ensure that the file is newly created or error out if already existing.
+    pub exclusive: bool,
+    /// Duplicate logged messages to STDOUT, like tee
+    pub to_stdout: bool,
+    /// Prefix messages logged to the file with the current local time as RFC 3339
+    pub prefix_time: bool,
+    /// File owner/group and mode
+    pub file_opts: CreateOptions,
+}
+
+/// Log messages with optional automatically added timestamps into files
+///
+/// #### Example:
+/// ```
+/// # use anyhow::{bail, format_err, Error};
+/// use proxmox_log::{flog, FileLogger, FileLogOptions};
+///
+/// # std::fs::remove_file("test.log");
+/// let options = FileLogOptions {
+///     to_stdout: true,
+///     exclusive: true,
+///     ..Default::default()
+/// };
+/// let mut log = FileLogger::new("test.log", options).unwrap();
+/// flog!(log, "A simple log: {}", "Hello!");
+/// # std::fs::remove_file("test.log");
+/// ```
+pub struct FileLogger {
+    file: std::fs::File,
+    file_name: std::path::PathBuf,
+    options: FileLogOptions,
+}
+
+/// Log messages to [FileLogger] - ``println`` like macro
+#[macro_export]
+macro_rules! flog {
+    ($log:expr, $($arg:tt)*) => ({
+        $log.log(format!($($arg)*));
+    })
+}
+
+impl FileLogger {
+    /// Create a new FileLogger. This opens the specified file and
+    /// stores a file descriptor.
+    pub fn new<P: AsRef<std::path::Path>>(
+        file_name: P,
+        options: FileLogOptions,
+    ) -> Result<Self, Error> {
+        let file = Self::open(&file_name, &options)?;
+
+        let file_name: std::path::PathBuf = file_name.as_ref().to_path_buf();
+
+        Ok(Self {
+            file,
+            file_name,
+            options,
+        })
+    }
+
+    /// Reopen logfile.
+    pub fn reopen(&mut self) -> Result<&Self, Error> {
+        let file = Self::open(&self.file_name, &self.options)?;
+        self.file = file;
+        Ok(self)
+    }
+
+    fn open<P: AsRef<std::path::Path>>(
+        file_name: P,
+        options: &FileLogOptions,
+    ) -> Result<std::fs::File, Error> {
+        let mut flags = OFlag::O_CLOEXEC;
+
+        if options.read {
+            flags |= OFlag::O_RDWR;
+        } else {
+            flags |= OFlag::O_WRONLY;
+        }
+
+        if options.append {
+            flags |= OFlag::O_APPEND;
+        }
+        if options.exclusive {
+            flags |= OFlag::O_EXCL;
+        }
+
+        let file =
+            atomic_open_or_create_file(&file_name, flags, &[], options.file_opts.clone(), false)?;
+
+        Ok(file)
+    }
+
+    /// Writes `msg` to the logfile with a timestamp and to stdout if
+    /// specified.
+    pub fn log<S: AsRef<str>>(&mut self, msg: S) {
+        let msg = msg.as_ref();
+
+        if self.options.to_stdout {
+            let mut stdout = std::io::stdout();
+            let _ = stdout.write_all(msg.as_bytes());
+            let _ = stdout.write_all(b"\n");
+        }
+
+        let line = if self.options.prefix_time {
+            let now = proxmox_time::epoch_i64();
+            let rfc3339 = match proxmox_time::epoch_to_rfc3339(now) {
+                Ok(rfc3339) => rfc3339,
+                Err(_) => "1970-01-01T00:00:00Z".into(), // for safety, should really not happen!
+            };
+            format!("{rfc3339}: {msg}\n")
+        } else {
+            format!("{msg}\n")
+        };
+        // Note: we ignore the potential error here because log methods
+        // shouldn't panic. We also can't log an error, because that
+        // would lead to recursion.
+        let _ = self.file.write_all(line.as_bytes());
+    }
+}
+
+impl std::io::Write for FileLogger {
+    fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
+        if self.options.to_stdout {
+            let _ = std::io::stdout().write(buf);
+        }
+        self.file.write(buf)
+    }
+
+    fn flush(&mut self) -> Result<(), std::io::Error> {
+        if self.options.to_stdout {
+            let _ = std::io::stdout().flush();
+        }
+        self.file.flush()
+    }
+}

proxmox-log/src/lib.rs

@@ -0,0 +1,48 @@
+use std::{
+    cell::{Cell, RefCell},
+    env,
+};
+
+use tracing::Level;
+use tracing_log::{AsLog, LogTracer};
+use tracing_subscriber::filter::{filter_fn, LevelFilter};
+use tracing_subscriber::prelude::*;
+
+use tasklog_layer::TasklogLayer;
+
+mod file_logger;
+pub use file_logger::{FileLogOptions, FileLogger};
+
+mod tasklog_layer;
+
+tokio::task_local! {
+    pub static LOGGER: RefCell<FileLogger>;
+    pub static WARN_COUNTER: Cell<u64>;
+}
+
+pub fn init_logger(
+    env_var_name: &str,
+    default_log_level: LevelFilter,
+    _application_name: &str,
+) -> Result<(), anyhow::Error> {
+    let mut log_level = default_log_level;
+    if let Ok(v) = env::var(env_var_name) {
+        if let Ok(l) = v.parse::<LevelFilter>() {
+            log_level = l;
+        }
+    }
+    let registry = tracing_subscriber::registry()
+        .with(
+            tracing_journald::layer()
+                .expect("Unable to open syslog")
+                .with_filter(log_level)
+                .with_filter(filter_fn(|metadata| {
+                    LOGGER.try_with(|_| {}).is_err() || *metadata.level() == Level::ERROR
+                })),
+        )
+        .with(TasklogLayer {}.with_filter(log_level));
+
+    tracing::subscriber::set_global_default(registry)?;
+    LogTracer::init_with_filter(log_level.as_log())?;
+    Ok(())
+}

proxmox-log/src/tasklog_layer.rs

@@ -0,0 +1,58 @@
+use std::fmt::Write as _;
+
+use tracing::field::Field;
+use tracing::field::Visit;
+use tracing::Event;
+use tracing::Level;
+use tracing::Subscriber;
+use tracing_subscriber::layer::Context;
+use tracing_subscriber::Layer;
+
+use crate::FileLogger;
+use crate::LOGGER;
+use crate::WARN_COUNTER;
+
+pub struct TasklogLayer;
+
+impl<S: Subscriber> Layer<S> for TasklogLayer {
+    fn on_event(&self, event: &Event<'_>, _ctx: Context<'_, S>) {
+        let _result = LOGGER.try_with(|logger| {
+            let mut buf = String::new();
+            event.record(&mut EventVisitor::new(&mut buf));
+            let level = event.metadata().level();
+            log_to_file(&mut logger.borrow_mut(), level, &buf);
+        });
+    }
+}
+
+fn log_to_file(logger: &mut FileLogger, level: &Level, buf: &String) {
+    match *level {
+        Level::ERROR | Level::WARN => {
+            WARN_COUNTER.with(|counter| {
+                counter.set(counter.get() + 1);
+            });
+            logger.log(buf);
+        }
+        Level::INFO => logger.log(buf),
+        Level::DEBUG => logger.log(format!("DEBUG: {buf}")),
+        Level::TRACE => logger.log(format!("TRACE: {buf}")),
+    };
+}
+
+struct EventVisitor<'a> {
+    buf: &'a mut String,
+}
+
+impl<'a> EventVisitor<'a> {
+    fn new(buf: &'a mut String) -> Self {
+        Self { buf }
+    }
+}
+
+impl Visit for EventVisitor<'_> {
+    fn record_debug(&mut self, field: &Field, value: &dyn std::fmt::Debug) {
+        if field.name() == "message" {
+            let _ = write!(self.buf, "{value:?}");
+        }
+    }
+}