add tracing init_cli_logger and deprecate old one

Deprecate the proxmox-router init_cli_logger function used in client
binaries such as `proxmox-backup-client`, `proxmox-backup-manager`,
'pxar', etc... Add a new init_cli_logger function that uses tracing
instead of env_logger. It checks if the task is in a workertask and
prints the message either to stdout or to the tasklog (this is
neccessary for commands in proxmox-backup-manager that call api handlers
that start workerthreads from the client).

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>

proxmox-log/src/lib.rs

@@ -8,7 +8,7 @@ use std::sync::{Arc, Mutex};
 use tokio::task::futures::TaskLocalFuture;
 use tracing::Level;
 use tracing_log::{AsLog, LogTracer};
-use tracing_subscriber::filter::{filter_fn, LevelFilter};
+use tracing_subscriber::filter::filter_fn;
 use tracing_subscriber::prelude::*;
 
 use tasklog_layer::TasklogLayer;
@@ -32,6 +32,7 @@ pub use tracing::trace;
 pub use tracing::trace_span;
 pub use tracing::warn;
 pub use tracing::warn_span;
+pub use tracing_subscriber::filter::LevelFilter;
 
 tokio::task_local! {
     static LOG_CONTEXT: LogContext;
@@ -125,3 +126,42 @@ impl LogContext {
         &self.logger
     }
 }
+
+/// Initialize default logger for CLI binaries
+pub fn init_cli_logger(
+    env_var_name: &str,
+    default_log_level: LevelFilter,
+) -> Result<(), anyhow::Error> {
+    let mut log_level = default_log_level;
+    if let Ok(v) = env::var(env_var_name) {
+        match v.parse::<LevelFilter>() {
+            Ok(l) => {
+                log_level = l;
+            },
+            Err(e) => {
+                eprintln!("env variable PBS_LOG found, but parsing failed: {e:?}");
+            }
+        }
+    }
+
+    let format = tracing_subscriber::fmt::format()
+        .with_level(false)
+        .without_time()
+        .with_target(false)
+        .compact();
+
+    let registry = tracing_subscriber::registry()
+        .with(
+            tracing_subscriber::fmt::layer()
+                .event_format(format)
+                .with_filter(filter_fn(|metadata| {
+                    !LogContext::exists() || *metadata.level() >= Level::ERROR
+                }))
+                .with_filter(log_level),
+        )
+        .with(TasklogLayer {}.with_filter(log_level));
+
+    tracing::subscriber::set_global_default(registry)?;
+    LogTracer::init_with_filter(log_level.as_log())?;
+    Ok(())
+}

proxmox-router/src/cli/mod.rs

@@ -58,6 +58,7 @@ pub use readline::*;
 pub type CompletionFunction = fn(&str, &HashMap<String, String>) -> Vec<String>;
 
 /// Initialize default logger for CLI binaries
+#[deprecated = "use proxmox_log::init_cli_logger instead"]
 pub fn init_cli_logger(env_var_name: &str, default_log_level: &str) {
     env_logger::Builder::from_env(
         env_logger::Env::new().filter_or(env_var_name, default_log_level),