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About the developer

leisim
821 Stars 82 Forks MIT License 96 Commits 36 Opened issues

Description

Small, easy to use and extensible logger which prints beautiful logs.

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Logger

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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:

Getting Started

Just create an instance of

Logger
and start logging: ```dart var logger = Logger();

logger.d("Logger is working!"); ```

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.v("Verbose log");

logger.d("Debug log");

logger.i("Info log");

logger.w("Warning log");

logger.e("Error log");

logger.wtf("What a terrible failure log");

To show only specific log levels, you can set:

Logger.level = Level.warning;

This hides all

verbose
,
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)
);

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
    printTime: false // Should each log print contain a timestamp
  ),
);

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. In release mode all logs are omitted.

You can create your own

LogFilter
like this:
dart
class MyFilter extends LogFilter {
  @override
  bool shouldLog(LogEvent event) {
    return true;
  }
}
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:

dart
class MyPrinter extends LogPrinter {
  @override
  List log(LogEvent event) {
    return [event.message];
  }
}

If you created a cool

LogPrinter
which might be helpful to others, feel free to open a pull request. :)

Colors

Please note that all IDEs (VSCode, XCode, Android Studio, IntelliJ) do not support ANSI escape sequences in their terminal outputs. These escape sequences are used to color output. If using such an IDE do not configure colored output.

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 achieved colored logs for any logger:

var logger = Logger(
  printer: PrefixPrinter(PrettyPrinter(colors: false))
);

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);
    }
  }
}

Possible future

LogOutput
s could send to a file, firebase or to Logcat. Feel free to open pull requests.

logger_flutter extension

The logger_flutter package is an extension for logger. You can add it to any Flutter app. Just shake the phone to show the console.

MIT License

Copyright (c) 2019 Simon Leier

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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