From 0bcf9a676ef7aaecf1f9be25a3791d4596b027c9 Mon Sep 17 00:00:00 2001
From: udo <udo@openfu.com>
Date: Tue, 14 Jul 2026 22:15:13 +0000
Subject: [PATCH] flush runtime diagnostics promptly

---
 docs/wasm-runtime-architecture.md |  5 ++++
 scripts/run_cli_tests.sh          |  1 +
 scripts/test_log_timeliness.sh    | 48 +++++++++++++++++++++++++++++++
 src/linux_fastcgi.cpp             |  4 +++
 4 files changed, 58 insertions(+)
 create mode 100755 scripts/test_log_timeliness.sh

diff --git a/docs/wasm-runtime-architecture.md b/docs/wasm-runtime-architecture.md
index 6f0a723..06c6ea4 100644
--- a/docs/wasm-runtime-architecture.md
+++ b/docs/wasm-runtime-architecture.md
@@ -402,6 +402,11 @@ header free-functions are `inline`. The wasm backend exposes only declarations
   independently enforces the same canonical identity, and persisted failures
   are reused only when their recorded source path matches the current request.
 
+- **Log timeliness**: the base process line-buffers stdout before forking
+  workers, the proactive compiler, and the WebSocket broker. This keeps each
+  newline-terminated diagnostic attached to its actual journal time instead of
+  releasing an old block-buffered failure during unrelated later traffic.
+
 - **WebSocket end-to-end**: a headless client performs a raw WS handshake to
   `:HTTP_PORT` with path `/site/tests/websockets.ws.uce` (self-resolving
   `SCRIPT_FILENAME`) and asserts the `hello-ack` frame — exercising the full
diff --git a/scripts/run_cli_tests.sh b/scripts/run_cli_tests.sh
index 309173f..b82b23c 100755
--- a/scripts/run_cli_tests.sh
+++ b/scripts/run_cli_tests.sh
@@ -69,4 +69,5 @@ if [[ "$action" == "run" ]]; then
 	scripts/test_dependency_invalidation.sh
 	scripts/test_cold_component_deadline.sh
 	scripts/test_password_hashing.sh
+	scripts/test_log_timeliness.sh
 fi
diff --git a/scripts/test_log_timeliness.sh b/scripts/test_log_timeliness.sh
new file mode 100755
index 0000000..d5e2ee2
--- /dev/null
+++ b/scripts/test_log_timeliness.sh
@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+test_name="log-timeliness-test-$$"
+site_directory="${UCE_TEST_SITE_DIRECTORY:-site}"
+if [[ -z "${UCE_TEST_SITE_DIRECTORY:-}" && -r /etc/uce/settings.cfg ]]; then
+	configured_site_directory=$(awk -F= '/^[[:space:]]*SITE_DIRECTORY[[:space:]]*=/ {gsub(/^[[:space:]]+|[[:space:]]+$/, "", $2); print $2; exit}' /etc/uce/settings.cfg)
+	if [[ -n "${configured_site_directory:-}" ]]; then
+		site_directory="$configured_site_directory"
+	fi
+fi
+source_dir="$site_directory/$test_name"
+bin_directory="${BIN_DIRECTORY:-}"
+if [[ -z "$bin_directory" && -r /etc/uce/settings.cfg ]]; then
+	bin_directory=$(awk -F= '/^[[:space:]]*BIN_DIRECTORY[[:space:]]*=/ {gsub(/^[[:space:]]+|[[:space:]]+$/, "", $2); print $2; exit}' /etc/uce/settings.cfg)
+fi
+bin_directory="${bin_directory:-/tmp/uce/work}"
+cache_dir=""
+
+cleanup() {
+	rm -rf "$source_dir"
+	if [[ -n "$cache_dir" ]]; then
+		rm -rf "$cache_dir"
+	fi
+}
+trap cleanup EXIT
+mkdir -p "$source_dir"
+cache_dir="$bin_directory$(realpath "$source_dir")"
+
+printf '%s\n' 'CLI(Request& context) { deliberate_log_timeliness_compile_failure }' >"$source_dir/probe.uce"
+rm -rf "$cache_dir"
+started_at=$(date '+%Y-%m-%d %H:%M:%S')
+
+set +e
+scripts/uce-cli "/$test_name/probe.uce" >/dev/null 2>&1
+set -e
+
+for _ in $(seq 1 20); do
+	if journalctl -u uce --since "$started_at" --no-pager | grep -Fq "$test_name/probe.uce"; then
+		echo "log timeliness passed"
+		exit 0
+	fi
+	sleep 0.1
+done
+
+echo "compile diagnostic was not journaled promptly: $test_name/probe.uce" >&2
+exit 1
diff --git a/src/linux_fastcgi.cpp b/src/linux_fastcgi.cpp
index 5133873..9e98eb3 100644
--- a/src/linux_fastcgi.cpp
+++ b/src/linux_fastcgi.cpp
@@ -1467,6 +1467,10 @@ void init_base_process()
 
 int main(int argc, char** argv)
 {
+	// systemd connects stdout to a pipe, which otherwise block-buffers child
+	// diagnostics and assigns stale failures a misleading later journal time.
+	setvbuf(stdout, 0, _IOLBF, 0);
+	setvbuf(stderr, 0, _IONBF, 0);
 	// Warm up libgcc's backtrace state so the first in-handler backtrace()
 	// after a fault does not allocate.
 	backtrace(request_fault_frames, 4);