cherrypick/website/docs/advanced-features/logging.md

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Logging

CherryPick lets you log all dependency injection (DI) events and errors using a flexible observer mechanism.

Custom Observers

You can pass any implementation of CherryPickObserver to your root scope or any sub-scope. This allows centralized and extensible logging, which you can direct to print, files, visualization frameworks, external loggers, or systems like Talker.

Example: Printing All Events

import 'package:cherrypick/cherrypick.dart';

void main() {
  // Use the built-in PrintCherryPickObserver for console logs
  final observer = PrintCherryPickObserver();
  final scope = CherryPick.openRootScope(observer: observer);
  // All DI actions and errors will now be printed!
}

Example: Advanced Logging with Talker

For richer logging, analytics, or UI overlays, use an advanced observer such as talker_cherrypick_logger:

import 'package:cherrypick/cherrypick.dart';
import 'package:talker/talker.dart';
import 'package:talker_cherrypick_logger/talker_cherrypick_logger.dart';

void main() {
  final talker = Talker();
  final observer = TalkerCherryPickObserver(talker);
  CherryPick.openRootScope(observer: observer);
  // All container events go to the Talker log system!
}

Default Behavior

• By default, logging is silent (SilentCherryPickObserver) for production, with no output unless you supply an observer.
• You can configure observers per scope for isolated, test-specific, or feature-specific logging.

Observer Capabilities

Events you can observe and log:

• Dependency registration
• Instance requests, creations, disposals
• Module installs/removals
• Scope opening/closing
• Cache hits/misses
• Cycle detection
• Diagnostics, warnings, errors

Just implement or extend CherryPickObserver and direct messages anywhere you want!

When to Use

• Enable verbose logging and debugging in development or test builds.
• Route logs to your main log system or analytics.
• Hook into DI lifecycle for profiling or monitoring.