From 972ed6d0944eb27faded27825f8c0fa5761097f8 Mon Sep 17 00:00:00 2001
From: Noah Gold <nkgold@google.com>
Date: Fri, 17 Jun 2022 17:50:32 -0700
Subject: [PATCH] base: log with local timestamps instead of UTC

00068bc0a2f02bd79235ff50b9d6f81a6133986f caused the timestamps on
crosvm logs to switch to UTC (ISO 8601). The 8601 part is great,
but the UTC time is a little annoying for local debugging.

Thanks to auradkar@ for coming up with the new formatter code.

BUG=b:236004673
TEST=ran downstream crosvm & verified logs appear w/ local timestamps.

Change-Id: I715f68b7f4ba545e3eadbfd1b9be9abba69d8258
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3712544
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Vikram Auradkar <auradkar@google.com>
Commit-Queue: Noah Gold <nkgold@google.com>
---
 base/src/syslog.rs | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/base/src/syslog.rs b/base/src/syslog.rs
index 4a4f2e2b07..145e00f8ba 100644
--- a/base/src/syslog.rs
+++ b/base/src/syslog.rs
@@ -49,8 +49,9 @@
 //!
 //! [log-crate-url]: https://docs.rs/log/
 
-use std::{fmt::Display, io};
+use std::{fmt::Display, io, io::Write};
 
+use chrono::Local;
 use once_cell::sync::OnceCell;
 use remain::sorted;
 use serde::{Deserialize, Serialize};
@@ -247,8 +248,25 @@ impl State {
         builder.parse(cfg.filter);
         let filter = builder.build();
 
-        if cfg.stderr {
+        let create_formatted_builder = || {
             let mut builder = env_logger::Builder::new();
+
+            // Output log lines w/ local ISO 8601 timestamps.
+            builder.format(|buf, record| {
+                writeln!(
+                    buf,
+                    "[{} {:5} {}] {}",
+                    Local::now().format("%Y-%m-%dT%H:%M:%S%:z"),
+                    record.level(),
+                    record.module_path().unwrap_or("<missing module path>"),
+                    record.args()
+                )
+            });
+            builder
+        };
+
+        if cfg.stderr {
+            let mut builder = create_formatted_builder();
             builder.filter_level(log::LevelFilter::Trace);
             builder.target(env_logger::Target::Stderr);
             loggers.push(Box::new(builder.build()));
@@ -259,7 +277,7 @@ impl State {
         }
 
         if let Some(file) = cfg.pipe {
-            let mut builder = env_logger::Builder::new();
+            let mut builder = create_formatted_builder();
             builder.filter_level(log::LevelFilter::Trace);
             builder.target(env_logger::Target::Pipe(Box::new(file)));
             // https://github.com/env-logger-rs/env_logger/issues/208