Apache DolphinScheduler 限制秒级别的定时调度

背景

Apache DolphinScheduler 定时任务配置采用的 7 位 Crontab 表达式，分别对应秒、分、时、月天、月、周天、年。

在团队日常开发工作中，工作流的定时调度一般不会细化到秒级别。但历史上出现过因配置的疏忽大意而产生故障时间，如应该配置每分钟执行的工作流被配置长了每秒执行，造成短时间内产生大量工作流实例，对 Apache DolphinScheduler 服务可用性和提交任务的 Hadoop 集群造成影响。

基于此，团队决定将 DolphinScheduler 中定时任务配置模块的 Crontab 表达式做限制，从平台侧杜绝此类事件发生。

方案

我们的方案是从前后端双方面限制 Crontab 表达式的第一位：

• 前端配置选择不提供“每一秒钟”选项
• 服务端接口判断第一位为 * 时，返回错误

前端修改

在前端项目中，秒、分、时 均为统一模版（CrontabTime），因此新增 dolphinscheduler-ui/src/components/crontab/modules/second.tsx

只保留两种模式：intervalTime 和 specificTime

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
import _ from 'lodash'
import { defineComponent, onMounted, PropType, ref, toRefs, watch } from 'vue'
import { NInputNumber, NRadio, NRadioGroup, NSelect } from 'naive-ui'
import { useI18n } from 'vue-i18n'
import { ICrontabI18n } from '../types'
import { isStr, specificList } from '../common'
import styles from '../index.module.scss'
 
const props = {
    timeMin: {
        type: Number as PropType<number>,
        default: 0
    },
    timeMax: {
        type: Number as PropType<number>,
        default: 60
    },
    intervalPerform: {
        type: Number as PropType<number>,
        default: 5
    },
    intervalStart: {
        type: Number as PropType<number>,
        default: 3
    },
    timeSpecial: {
        type: Number as PropType<number | string>,
        default: 60
    },
    timeValue: {
        type: String as PropType<string>,
        default: '*'
    },
    timeI18n: {
        type: Object as PropType<ICrontabI18n>,
        require: true
    }
}
 
export default defineComponent({
    name: 'CrontabSecond',
    props,
    emits: ['update:timeValue'],
    setup(props, ctx) {
        const options = Array.from({ length: 60 }, (x, i) => ({
            label: i.toString(),
            value: i
        }))
 
        const timeRef = ref()
        const radioRef = ref()
        const intervalStartRef = ref(props.intervalStart)
        const intervalPerformRef = ref(props.intervalPerform)
        const specificTimesRef = ref<Array<number>>([])
 
        /**
         * Parse parameter value
         */
        const analyticalValue = () => {
            const $timeVal = props.timeValue
            // Interval time
            const $interval = isStr($timeVal, '/')
            // Specific time
            const $specific = isStr($timeVal, ',')
 
            // Positive integer (times)
            if (
                ($timeVal.length === 1 ||
                    $timeVal.length === 2 ||
                    $timeVal.length === 4) &&
                _.isInteger(parseInt($timeVal))
            ) {
                radioRef.value = 'specificTime'
                specificTimesRef.value = [parseInt($timeVal)]
                return
            }
 
            // Interval times
            if ($interval) {
                radioRef.value = 'intervalTime'
                intervalStartRef.value = parseInt($interval[0])
                intervalPerformRef.value = parseInt($interval[1])
                timeRef.value = `${intervalStartRef.value}/${intervalPerformRef.value}`
                return
            }
 
            // Specific times
            if ($specific) {
                radioRef.value = 'specificTime'
                specificTimesRef.value = $specific.map((item) => parseInt(item))
                return
            }
        }
 
        // Interval start time（1）
        const onIntervalStart = (value: number | null) => {
            intervalStartRef.value = value || 0
            if (radioRef.value === 'intervalTime') {
                timeRef.value = `${intervalStartRef.value}/${intervalPerformRef.value}`
            }
        }
 
        // Interval execution time（2）
        const onIntervalPerform = (value: number | null) => {
            intervalPerformRef.value = value || 0
            if (radioRef.value === 'intervalTime') {
                timeRef.value = `${intervalStartRef.value}/${intervalPerformRef.value}`
            }
        }
 
        // Specific time
        const onSpecificTimes = (arr: Array<number>) => {
            specificTimesRef.value = arr
            if (radioRef.value === 'specificTime') {
                specificReset()
            }
        }
 
        // Reset interval time
        const intervalReset = () => {
            timeRef.value = `${intervalStartRef.value}/${intervalPerformRef.value}`
        }
 
        // Reset specific time
        const specificReset = () => {
            let timeValue = '0'
            if (specificTimesRef.value.length) {
                timeValue = specificTimesRef.value.join(',')
            }
            timeRef.value = timeValue
        }
 
        const updateRadioTime = (value: string) => {
            switch (value) {
                case 'intervalTime':
                    intervalReset()
                    break
                case 'specificTime':
                    specificReset()
                    break
            }
        }
 
        watch(
            () => timeRef.value,
            () => ctx.emit('update:timeValue', timeRef.value.toString())
        )
 
        onMounted(() => analyticalValue())
 
        return {
            options,
            radioRef,
            intervalStartRef,
            intervalPerformRef,
            specificTimesRef,
            updateRadioTime,
            onIntervalStart,
            onIntervalPerform,
            onSpecificTimes,
            ...toRefs(props)
        }
    },
    render() {
        const { t } = useI18n()
 
        return (
            <NRadioGroup
                v-model:value={this.radioRef}
                onUpdateValue={this.updateRadioTime}
            >
                <div class={styles['crontab-list']}>
                    <NRadio value={'intervalTime'} />
                    <div class={styles['crontab-list-item']}>
                        <div class={styles['item-text']}>{t(this.timeI18n!.every)}</div>
                        <div class={styles['number-input']}>
                            <NInputNumber
                                defaultValue={5}
                                min={this.timeMin}
                                max={this.timeMax}
                                v-model:value={this.intervalPerformRef}
                                onUpdateValue={this.onIntervalPerform}
                            />
                        </div>
                        <div class={styles['item-text']}>
                                {t(this.timeI18n!.timeCarriedOut)}
                        </div>
                        <div class={styles['number-input']}>
                            <NInputNumber
                                defaultValue={3}
                                min={this.timeMin}
                                max={this.timeMax}
                                v-model:value={this.intervalStartRef}
                                onUpdateValue={this.onIntervalStart}
                            />
                        </div>
                        <div class={styles['item-text']}>{t(this.timeI18n!.timeStart)}</div>
                    </div>
                </div>
                <div class={styles['crontab-list']}>
                    <NRadio value={'specificTime'} />
                    <div class={styles['crontab-list-item']}>
                        <div>{t(this.timeI18n!.specificTime)}</div>
                        <div class={styles['select-input']}>
                            <NSelect
                                multiple
                                options={specificList[this.timeSpecial]}
                                placeholder={t(this.timeI18n!.specificTimeTip)}
                                v-model:value={this.specificTimesRef}
                                onUpdateValue={this.onSpecificTimes}
                            />
                        </div>
                    </div>
                </div>
            </NRadioGroup>
        )
    }
})

服务端

添加Crontab表达式检验（有两处：一处是新增Post接口、另一处是修改PUT接口），直接添加个检测方法供这两处调用：

        if (scheduleParam.getCrontab().startsWith("*")) {
            logger.error("The crontab must not start with *");
            putMsg(result, Status.CRONTAB_EVERY_SECOND_ERROR);
            return result;
        }

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