logger: allow to use a custom sink and log level logic

common/changes/@subsquid/logger/master_2024-12-23-14-20.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@subsquid/logger",
+      "comment": "allow to use custom log sink and level determination logic",
+      "type": "minor"
+    }
+  ],
+  "packageName": "@subsquid/logger"
+}

util/logger/src/index.ts

@@ -1,17 +1,44 @@
-import {Logger} from "./logger"
-import {jsonLinesStderrSink} from "./sinks/json"
-import {prettyStderrSink} from "./sinks/pretty"
+import {LEVELS, LogLevel} from './level'
+import {Logger, Sink} from './logger'
+import {jsonLinesStderrSink} from './sinks/json'
+import {prettyStderrSink} from './sinks/pretty'
+
 
 export {LogLevel} from "./level"
 export * from "./logger"
 
+
+/**
+ * Override the default log level determination logic.
+ *
+ * Log levels are cached.
+ * Call it at the very beginning of the app for it to be effective.
+ *
+ * Return `undefined` from the `cb` to fall back to the standard logic.
+ */
+export function setLogLevelCallback(cb?: (ns: string) => LogLevel | undefined): void {
+    LEVELS.setLevelCallback(cb)
+}
+
+
 const prettyEnabled = process.env.FORCE_PRETTY_LOGGER ?
     process.env.FORCE_PRETTY_LOGGER !== '0' :
     process.stderr.isTTY
 
 
+let ROOT_SINK = prettyEnabled ? prettyStderrSink : jsonLinesStderrSink
+
+
+/**
+ * Use custom log sink
+ */
+export function setRootSink(sink: Sink): void {
+    ROOT_SINK = sink
+}
+
+
 const ROOT = new Logger(
-    prettyEnabled ? prettyStderrSink : jsonLinesStderrSink,
+    rec => ROOT_SINK(rec),
     ''
 )
 

util/logger/src/level.ts

@@ -55,6 +55,7 @@ function noMatch(ns: string): Specificity {
 export class Levels {
     private cache: Record<string, LogLevel> = {}
     private levels: NamespaceMatcher[] = [noMatch, noMatch, noMatch, noMatch, noMatch, noMatch]
+    private namespaceLevel?: (ns: string) => LogLevel | undefined
 
     get(ns: string): LogLevel {
         let level = this.cache[ns]
@@ -65,9 +66,15 @@ export class Levels {
         }
     }
 
+    setLevelCallback(cb?: (ns: string) => LogLevel | undefined): void {
+        this.namespaceLevel = cb
+    }
+
     private determineLevel(ns: string): LogLevel {
+        let level = this.namespaceLevel?.(ns)
+        if (level != null) return level
+        level = LogLevel.INFO
         let specificity = 0
-        let level = LogLevel.INFO
         for (let i = 0; i < this.levels.length; i++) {
             let s = this.levels[i](ns)
             if (s > specificity) {