Initial fluentd support (#205)

* fix(hack): use sudo -E when running Rust binaries

This makes it possible to pass envvars to the Krata runtime

* feat(o11y): add fluent sink to logs

This change adds fluent logging as an opt-in feature. Setting
`KRATA_LOG_FLUENT` with an address:port will start a TCP connection,
sending logs.

A later changes will respect a URI scheme and use structured logging.

crates/daemon/bin/daemon.rs

@@ -1,15 +1,41 @@
+use std::{
+    net::{SocketAddr, TcpStream},
+    str::FromStr,
+    sync::{atomic::AtomicBool, Arc},
+};
+
 use anyhow::Result;
 use clap::Parser;
-use env_logger::Env;
-use kratad::command::DaemonCommand;
+use env_logger::fmt::Target;
 use log::LevelFilter;
-use std::sync::{atomic::AtomicBool, Arc};
+
+use kratad::command::DaemonCommand;
 
 #[tokio::main(flavor = "multi_thread", worker_threads = 10)]
 async fn main() -> Result<()> {
-    env_logger::Builder::from_env(Env::default().default_filter_or("info"))
-        .filter(Some("backhand::filesystem::writer"), LevelFilter::Warn)
-        .init();
+    let mut builder = env_logger::Builder::new();
+    builder
+        .filter_level(LevelFilter::Trace)
+        .parse_default_env()
+        .filter(Some("backhand::filesystem::writer"), LevelFilter::Warn);
+
+    if let Ok(f_addr) = std::env::var("KRATA_FLUENT_ADDR") {
+        println!("KRATA_FLUENT_ADDR set to {f_addr}");
+        let target = SocketAddr::from_str(f_addr.as_str())?;
+        builder.target(Target::Pipe(Box::new(TcpStream::connect(target)?)));
+    }
+
+    let ev = std::env::vars()
+        .into_iter()
+        .fold(String::new(), |mut acc, (k, v)| {
+            acc.push_str(&format!("{k}={v}\n"));
+            acc
+        });
+
+    std::fs::write("/var/log/krata/ev", ev)?;
+
+    builder.init();
+
     mask_sighup()?;
 
     let command = DaemonCommand::parse();

crates/daemon/src/event.rs

@@ -9,7 +9,7 @@ use krata::{
     idm::{internal::event::Event as EventType, internal::Event},
     v1::common::{GuestExitInfo, GuestState, GuestStatus},
 };
-use log::{error, warn};
+use log::{error, info, warn};
 use tokio::{
     select,
     sync::{
@@ -90,6 +90,7 @@ impl DaemonEventGenerator {
         let status = state.status();
         let id = Uuid::from_str(&guest.id)?;
         let domid = state.domid;
+        info!("Guest {} on Zone {} changed - {:?}", id, domid, status);
         match status {
             GuestStatus::Started => {
                 if let Entry::Vacant(e) = self.idms.entry(domid) {

hack/debug/common.sh

@@ -28,5 +28,5 @@ build_and_run() {
   fi
   RUST_TARGET="$(./hack/build/target.sh)"
   ./hack/build/cargo.sh build ${CARGO_BUILD_FLAGS} --bin "${EXE_TARGET}"
-  exec sudo sh -c "RUST_LOG='${RUST_LOG}' 'target/${RUST_TARGET}/debug/${EXE_TARGET}' $*"
+  exec sudo -E sh -c "RUST_LOG='${RUST_LOG}' 'target/${RUST_TARGET}/debug/${EXE_TARGET}' $*"
 }