feat(kernel-cli): filter daemon log entries below a minimum severity

packages/kernel-cli/CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- The daemon log filters entries below a minimum severity, defaulting to `info`, so high-volume `debug` output (refcount churn and similar) no longer dominates `daemon.log`; set `$OCAP_DAEMON_LOG_LEVEL` to `debug` to record everything again ([#1008](https://github.com/MetaMask/ocap-kernel/pull/1008))
 - Relay state files (`relay.pid`, `relay.addr`) now live in their own directory (default `~/.libp2p-relay`, overridable via `$LIBP2P_RELAY_HOME`) instead of under `$OCAP_HOME`, so one libp2p relay can serve daemons with different OCAP_HOMEs ([#952](https://github.com/MetaMask/ocap-kernel/pull/952))
 
 ### Fixed

packages/kernel-cli/src/commands/daemon-entry.ts

@@ -11,11 +11,41 @@ import { join } from 'node:path';
 import { getOcapHome } from '../ocap-home.ts';
 import { isProcessAlive } from '../utils.ts';
 
+// Mirror of @metamask/logger's level ordering (`logLevels` is not part
+// of the package's public surface). Higher numbers are more severe.
+// Declared above the file-scope logger construction so the transport
+// factory doesn't hit a temporal-dead-zone reference when it's called
+// during module init.
+const LOG_LEVELS = {
+  debug: 1,
+  info: 2,
+  log: 3,
+  warn: 4,
+  error: 5,
+} as const;
+
+type LogLevelName = keyof typeof LOG_LEVELS;
+
+/**
+ * Resolve the daemon's minimum log level from `OCAP_DAEMON_LOG_LEVEL`.
+ * Defaults to `info` so noisy `debug` entries (refcount churn etc.)
+ * are dropped; set the env var to `debug` to re-enable everything.
+ *
+ * @returns The minimum log level to record.
+ */
+function resolveMinLogLevel(): LogLevelName {
+  const raw = process.env.OCAP_DAEMON_LOG_LEVEL;
+  if (raw !== undefined && raw in LOG_LEVELS) {
+    return raw as LogLevelName;
+  }
+  return 'info';
+}
+
 const ocapDir = getOcapHome();
 const logPath = join(ocapDir, 'daemon.log');
 const logger = new Logger({
   tags: ['daemon'],
-  transports: [makeFileTransport(logPath)],
+  transports: [makeFileTransport(logPath, resolveMinLogLevel())],
 });
 
 // Install exit-cause handlers at module load, before main() runs, so
@@ -139,13 +169,20 @@ async function readDaemonPid(pidPath: string): Promise<number | undefined> {
 }
 
 /**
- * Create a file transport that writes logs to a file.
+ * Create a file transport that writes logs to a file, filtering out
+ * entries below `minLevel`.
  *
  * @param logFilePath - The log file path.
+ * @param minLevel - Minimum severity to write; entries below this are
+ *   dropped silently.
  * @returns A log transport function.
  */
-function makeFileTransport(logFilePath: string) {
+function makeFileTransport(logFilePath: string, minLevel: LogLevelName) {
+  const minIdx = LOG_LEVELS[minLevel];
   return (entry: LogEntry): void => {
+    if (LOG_LEVELS[entry.level] < minIdx) {
+      return;
+    }
     const line = `[${new Date().toISOString()}] [${entry.level}] ${entry.message ?? ''} ${(entry.data ?? []).map(String).join(' ')}\n`;
     // eslint-disable-next-line n/no-sync -- synchronous write needed for log transport reliability
     appendFileSync(logFilePath, line);