气流for服务器对无时间间隔的dags给出cron错误。

Question

我在Linux中使用LocalExecutor和PostgreSQL数据库运行气流1.9.0。我想手动触发DAG，但是每当我创建一个schedule_interval设置为None或@once的DAG时，set服务器树视图就会崩溃，出现以下错误(我只显示最后一次调用)：

File "/usr/local/lib/python2.7/site-packages/croniter/croniter.py", line 467, in expand 
    raise CroniterBadCronError(cls.bad_length)
CroniterBadCronError: Exactly 5 or 6 columns has to be specified for iteratorexpression.

此外，当我手动触发DAG时，DAG运行将启动，但任务本身从未被调度。我环顾四周，但似乎我是唯一有这种错误的人。以前是否有人遇到过此错误，并找到了修补程序？

触发问题的最小示例：

import datetime as dt
from airflow import DAG
from airflow.operators.bash_operator import BashOperator

default_args = {
    'owner': 'me'
}

bash_command = """
    echo "this is a test task"
"""

with DAG('schedule_test',
        default_args=default_args,
        start_date = dt.datetime(2018, 7, 24),
        schedule_interval='None',
        catchup=False
        ) as dag:

    first_task = BashOperator(task_id = "first_task", bash_command = bash_command)

Answer 1

试试这个：

• 将您的schedule_interval设置为不带''的None，或者干脆不指定schedule_interval in your DAG。它被设置为None as a default。有关这方面的更多信息：气流文档 --搜索schedule_interval
• 在后台为您的任务设置编排。

就像这样：

import datetime
from airflow import DAG
from airflow.operators.bash_operator import BashOperator
from airflow.operators.dummy_operator import DummyOperator

default_args = {
    'owner': 'me'
}

bash_command = """
    echo "this is a test task"
"""

with DAG('schedule_test',
        default_args=default_args,
        start_date = datetime(2018, 7, 24),
        schedule_interval=None,
        catchup=False
        ) as dag:

t1 = DummyOperator(
    task_id='extract_data',
    dag=dag
)

t2 = BashOperator(
    task_id = "first_task", 
    bash_command = bash_command
)

#####ORCHESTRATION#####
## It is saying that in order for t2 to run, t1 must be done.
t2.set_upstream(t1)

Answer 2

无值不应在引号中

应该是这样的: schedule_interval=None

以下是文档链接：interval%3D%27None%27%20when%20you%20don%E2%80%99t%20want%20to%20schedule%20your%20DAG