batch 0.12.1

A lightweight and powerful Job Scheduling Framework written in Dart. With this framework, you can easily develop a job scheduling and batch program in Dart.

example/example.dart

// Copyright 2022 Kato Shinya. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided the conditions.

import 'dart:async';
import 'dart:io';

import 'package:batch/batch.dart';

void main(List<String> args) => BatchApplication(
      args: _argParser.parse(args),
      onLoadArgs: (args, addSharedParameters) {
        //! This callback is useful when you want to create a singleton instance using command line arguments
        //! and manage it as SharedParameters in batch application. If this callback is not defined,
        //! all command line arguments are added as SharedParameters automatically.
        addSharedParameters(key: 'userName', value: args['userName']);
      },
      logConfig: LogConfiguration(
        level: LogLevel.trace,
        output: MultiLogOutput([
          ConsoleLogOutput(),
          FileLogOutput(file: File('./test.txt')),
        ]),
        color: LogColor(
          info: ConsoleColor.cyan3,
        ),
        printLog: true,
      ),
    )
      // You can add any parameters that is shared in this batch application.
      ..addSharedParameter(key: 'key1', value: 'value1')
      ..addSharedParameter(key: 'key2', value: {'any': 'object'})
      ..addJob(_testJob1)
      ..addJob(_testJob2)
      ..addJob(_testJob4)
      ..run();

ArgParser get _argParser {
  // The well-known "args" library can be used as standard.
  // See more information about "args" at https://pub.dev/packages/args.
  final parser = ArgParser();
  parser.addOption('userName', abbr: 'u');
  parser.addOption('appName', abbr: 'a');
  parser.addFlag('release', abbr: 'r', defaultsTo: false);

  return parser;
}

Job get _testJob1 => Job(
      name: 'Job1',
      schedule: CronParser(value: '*/1 * * * *'),
      // You can define callbacks for each processing phase.
      onStarted: (context) =>
          log.info('\n--------------- Job1 has started! ---------------'),
      onCompleted: (context) =>
          log.info('\n--------------- Job1 has completed! ---------------'),
    )
      ..nextStep(
        Step(
          name: 'Step1',
          skipConfig: SkipConfiguration(
            skippableExceptions: [Exception()],
          ),
        )..registerTask(
            RetryTask(
              // You can define callbacks for each processing phase.
              onStarted: (context) => log.info(
                  '\n--------------- RetryTask has started! ---------------'),
              onSucceeded: (context) => log.info(
                  '\n--------------- RetryTask has succeeded! ---------------'),
              onError: (context, error, stackTrace) => log.error(
                '\n--------------- Error RetryTask ---------------',
                error,
                stackTrace,
              ),
              onCompleted: (context) => log.info(
                  '\n--------------- RetryTask has completed! ---------------'),
              retryConfig: RetryConfiguration(
                maxAttempt: 3,
                retryableExceptions: [Exception()],
                backOff: Duration(seconds: 30),
                onRecover: (context) {
                  log.warn('Do something for recovering.');
                },
              ),
            ),
          ),
      )
      ..nextStep(
        Step(name: 'Step2')
          ..registerTask(TestTask())
          ..createBranchOnSucceeded(
            to: Step(name: 'Step3')..registerTask(SayHelloTask()),
          )
          ..createBranchOnFailed(
            to: Step(name: 'Step4')
              ..registerTask(SayHelloTask())
              ..createBranchOnCompleted(
                to: Step(
                  name: 'Step6',
                  // You can set any preconditions to run Step.
                  precondition: (context) => false,
                )..registerTask(SayWorldTask()),
              ),
          )
          ..createBranchOnCompleted(
            to: Step(
              name: 'Step5',
              // You can define callbacks for each processing phase.
              onStarted: (context) => log
                  .info('\n--------------- Step5 has started! ---------------'),
              onCompleted: (context) => log.info(
                  '\n--------------- Step5 has completed! ---------------'),
            )..registerTask(SayHelloTask()),
          ),
      );

Job get _testJob2 => Job(
      name: 'Job2',
      schedule: CronParser(value: '*/5 * * * *'),
      // You can set any preconditions to run Job.
      precondition: (context) async => true,
    )
      ..nextStep(
        Step(
          name: 'Step1',
          precondition: (context) => true,
        )..registerTask(SayWorldTask()),
      )
      ..createBranchOnSucceeded(
        to: Job(name: 'Job3')..nextStep(Step(name: 'Step1')..shutdown()),
      );

Job get _testJob4 => Job(
      name: 'Job4',
      schedule: CronParser(value: '*/1 * * * *'),
      // You can set any preconditions to run Job.
      precondition: (context) async => true,
    )..nextStep(
        Step(
          name: 'Parallel Step',
          precondition: (context) => true,
        )..registerParallel(
            Parallel(
              name: 'Parallel Tasks',
              tasks: [
                TestParallelTask(),
                TestParallelTask(),
                TestParallelTask(),
                TestParallelTask(),
              ],
            ),
          ),
      );

class TestTask extends Task<TestTask> {
  @override
  void execute(ExecutionContext context) {
    // This parameter is shared just in this job.
    context.jobParameters['key'] = 'job_parameter';

    // You can use shared parameters in any places.
    log.info(context.sharedParameters['key1']);
    log.info(context.sharedParameters['key2']);

    log.trace('Trace');
    log.info('Info');
    log.debug('Debug');
    log.warn('Warn');
    log.error('Error');
    log.fatal('Fatal');
  }
}

class SayHelloTask extends Task<SayHelloTask> {
  @override
  void execute(ExecutionContext context) {
    log.debug('Hello,');
  }
}

class SayWorldTask extends Task<SayWorldTask> {
  @override
  void execute(ExecutionContext context) {
    log.info('World!');
    context.jobExecution!.switchBranchToSucceeded();
    context.stepExecution!.switchBranchToFailed();
  }
}

class RetryTask extends Task<RetryTask> {
  RetryTask({
    Function(ExecutionContext context)? onStarted,
    Function(ExecutionContext context)? onSucceeded,
    Function(ExecutionContext context, dynamic error, StackTrace stackTrace)?
        onError,
    Function(ExecutionContext context)? onCompleted,
    RetryConfiguration? retryConfig,
  }) : super(
          onStarted: onStarted,
          onSucceeded: onSucceeded,
          onError: onError,
          onCompleted: onCompleted,
          retryConfig: retryConfig,
        );

  /// The count for retry test
  static int count = 0;

  @override
  void execute(ExecutionContext context) {
    if (count < 3) {
      count++;
      throw Exception();
    } else {
      count = 0;
    }
  }
}

class TestParallelTask extends ParallelTask<TestParallelTask> {
  @override
  FutureOr<void> execute(ExecutionContext context) {
    int i = 0;
    while (i < 10000000000) {
      i++;
    }

    //! The logging functions provided by frameworks such as "log.info" and "info" cannot be
    //! used in parallel processing. Instead, use the "sendMessage" method corresponding
    //! to the log level as below.
    //!
    //! Messages sent by the following "sendMessage" method are logged out at once after
    //! parallel processing is completed.
    super.sendMessageAsTrace('Trace');
    super.sendMessageAsDebug('Debug');
    super.sendMessageAsInfo('Info');

    try {
      throw Exception('Error output is also possible.');
    } catch (error, stackTrace) {
      // The error and stackTrace are optional.
      super.sendMessageAsWarn('Warn');
      super.sendMessageAsError('Error', error, stackTrace);
      super.sendMessageAsFatal('Fatal', error, stackTrace);
    }
  }
}