feat: Replace log with tracing

Replaces `log` with `tracing` and the custom logger with
`tracing_subscriber::Fmt`.

Adding support for re-configuring the logger at run-time and
removing the old logger format.

Signed-off-by: Jonathan Woollett-Light <jcawl@amazon.co.uk>

Author: Jonathan Woollett-Light

Cargo.lock

@@ -21,6 +21,8 @@ mmds = { path = "../mmds" }
 seccompiler = { path = "../seccompiler" }
 utils = { path = "../utils" }
 vmm = { path = "../vmm" }
+tracing = { version = "0.1.37", default-features = false }
 
 [dev-dependencies]
 libc = "0.2.117"
+log = "0.4.19"

src/api_server/Cargo.toml

@@ -3,7 +3,7 @@
 
 use std::fmt::Debug;
 
-use logger::{error, info, log_enabled, Level};
+use logger::{error, info, Level};
 use micro_http::{Body, Method, Request, Response, StatusCode, Version};
 use serde::ser::Serialize;
 use serde_json::Value;
@@ -232,7 +232,7 @@ fn describe(method: Method, path: &str, body: Option<&Body>) -> String {
         ("/cpu-config", Some(payload_value)) => {
             // If the log level is at Debug or higher, include the CPU template in
             // the log line.
-            if log_enabled!(Level::Debug) {
+            if tracing::enabled!(Level::DEBUG) {
                 describe_with_body(method, path, payload_value)
             } else {
                 format!(

src/api_server/src/parsed_request.rs

@@ -22,7 +22,7 @@ pub(crate) fn parse_put_logger(body: &Body) -> Result<ParsedRequest, Error> {
 mod tests {
     use std::path::PathBuf;
 
-    use vmm::vmm_config::logger::LoggerLevel;
+    use vmm::vmm_config::logger::Level;
 
     use super::*;
     use crate::parsed_request::tests::vmm_action_from_request;
@@ -37,10 +37,10 @@ mod tests {
               }"#;
 
         let mut expected_cfg = LoggerConfig {
-            log_path: PathBuf::from("log"),
-            level: LoggerLevel::Warning,
-            show_level: false,
-            show_log_origin: false,
+            log_path: Some(PathBuf::from("log")),
+            level: Some(Level::Warn),
+            show_level: Some(false),
+            show_log_origin: Some(false),
         };
         match vmm_action_from_request(parse_put_logger(&Body::new(body)).unwrap()) {
             VmmAction::ConfigureLogger(cfg) => assert_eq!(cfg, expected_cfg),
@@ -55,10 +55,10 @@ mod tests {
               }"#;
 
         expected_cfg = LoggerConfig {
-            log_path: PathBuf::from("log"),
-            level: LoggerLevel::Debug,
-            show_level: false,
-            show_log_origin: false,
+            log_path: Some(PathBuf::from("log")),
+            level: Some(Level::Debug),
+            show_level: Some(false),
+            show_log_origin: Some(false),
         };
         match vmm_action_from_request(parse_put_logger(&Body::new(body)).unwrap()) {
             VmmAction::ConfigureLogger(cfg) => assert_eq!(cfg, expected_cfg),

src/api_server/src/request/logger.rs

@@ -17,6 +17,7 @@ libc = "0.2.147"
 serde = { version = "1.0.183", features = ["derive"] }
 serde_json = "1.0.104"
 thiserror = "1.0.44"
+tracing = { version = "0.1.37", default-features = false }
 
 vmm = { path = "../vmm" }
 

src/cpu-template-helper/Cargo.toml

@@ -11,6 +11,7 @@ bench = false
 [dependencies]
 bitflags = "1.3.2"
 derive_more = { version = "0.99.17", default-features = false, features = ["from"] }
+tracing = { version = "0.1.37", default-features = false }
 
 logger = { path = "../logger" }
 micro_http = { git = "https://github.com/firecracker-microvm/micro-http", rev = "4b18a04" }

src/dumbo/Cargo.toml

@@ -15,9 +15,12 @@ bench = false
 [dependencies]
 event-manager = "0.3.0"
 libc = "0.2.147"
+log = "0.4.19"
 serde_json = "1.0.104"
 thiserror = "1.0.44"
 timerfd = "1.5.0"
+tracing = { version = "0.1.37", default-features = false }
+tracing-subscriber = { version = "0.3.17", default-features = false, features = ["fmt"] }
 
 api_server = { path = "../api_server" }
 logger = { path = "../logger" }

src/firecracker/Cargo.toml

@@ -142,6 +142,7 @@ pub(crate) fn run_with_api(
     api_payload_limit: usize,
     mmds_size_limit: usize,
     metadata_json: Option<&str>,
+    logger_handles: vmm::vmm_config::logger::LoggerHandles,
 ) -> Result<(), ApiServerError> {
     // FD to notify of API events. This is a blocking eventfd by design.
     // It is used in the config/pre-boot loop which is a simple blocking loop
@@ -211,6 +212,7 @@ pub(crate) fn run_with_api(
             boot_timer_enabled,
             mmds_size_limit,
             metadata_json,
+            logger_handles,
         )
         .map_err(ApiServerError::MicroVMStoppedWithError),
     };