logger

Description:

logger

Logger #






Small, easy to use and extensible logger which prints beautiful logs.
Inspired by logger for Android.
Show some ❤️ and star the repo to support the project
Resources: #

Documentation
Pub Package
GitHub Repository

Getting Started #
Just create an instance of Logger and start logging:
var logger = Logger();

logger.d("Logger is working!");
copied to clipboard
Instead of a string message, you can also pass other objects like List, Map or Set.
Output #

Documentation #
Log level #
You can log with different levels:
logger.t("Trace log");

logger.d("Debug log");

logger.i("Info log");

logger.w("Warning log");

logger.e("Error log", error: 'Test Error');

logger.f("What a fatal log", error: error, stackTrace: stackTrace);
copied to clipboard
To show only specific log levels, you can set:
Logger.level = Level.warning;
copied to clipboard
This hides all trace, debug and info log events.
Options #
When creating a logger, you can pass some options:
var logger = Logger(
filter: null, // Use the default LogFilter (-> only log in debug mode)
printer: PrettyPrinter(), // Use the PrettyPrinter to format and print log
output: null, // Use the default LogOutput (-> send everything to console)
);
copied to clipboard
If you use the PrettyPrinter, there are more options:
var logger = Logger(
printer: PrettyPrinter(
methodCount: 2, // Number of method calls to be displayed
errorMethodCount: 8, // Number of method calls if stacktrace is provided
lineLength: 120, // Width of the output
colors: true, // Colorful log messages
printEmojis: true, // Print an emoji for each log message
// Should each log print contain a timestamp
dateTimeFormat: DateTimeFormat.onlyTimeAndSinceStart,
),
);
copied to clipboard
Auto detecting #
With the io package you can auto detect the lineLength and colors arguments.
Assuming you have imported the io package with import 'dart:io' as io; you
can auto detect colors with io.stdout.supportsAnsiEscapes and lineLength
with io.stdout.terminalColumns.
You should probably do this unless there's a good reason you don't want to
import io, for example when using this library on the web.
LogFilter #
The LogFilter decides which log events should be shown and which don't.
The default implementation (DevelopmentFilter) shows all logs with level >= Logger.level while
in debug mode (i.e., running dart with --enable-asserts).
In release mode all logs are omitted.
You can create your own LogFilter like this:
class MyFilter extends LogFilter {
@override
bool shouldLog(LogEvent event) {
return true;
}
}
copied to clipboard
This will show all logs even in release mode. (NOT a good idea)
LogPrinter #
The LogPrinter creates and formats the output, which is then sent to the LogOutput.
You can implement your own LogPrinter. This gives you maximum flexibility.
A very basic printer could look like this:
class MyPrinter extends LogPrinter {
@override
List<String> log(LogEvent event) {
return [event.message];
}
}
copied to clipboard
If you created a cool LogPrinter which might be helpful to others, feel free to open a pull
request.
:)
Colors #
Please note that in some cases ANSI escape sequences do not work under macOS.
These escape sequences are used to colorize the output.
This seems to be related to a Flutter bug that affects iOS builds:
https://github.com/flutter/flutter/issues/64491
However, if you are using a JetBrains IDE (Android Studio, IntelliJ, etc.)
you can make use of
the Grep Console Plugin
and the PrefixPrinter
decorator to achieve colored logs for any logger:
var logger = Logger(
printer: PrefixPrinter(PrettyPrinter(colors: false))
);
copied to clipboard
LogOutput #
LogOutput sends the log lines to the desired destination.
The default implementation (ConsoleOutput) send every line to the system console.
class ConsoleOutput extends LogOutput {
@override
void output(OutputEvent event) {
for (var line in event.lines) {
print(line);
}
}
}
copied to clipboard
Possible future LogOutputs could send to a file, firebase or to Logcat. Feel free to open pull
requests.
Acknowledgments #
This package was originally created by Simon Choi, with further
development by Harm Aarts, greatly enhancing its functionality over
time.