从 S3 开始的 Luigi Pipeline

Question

我的初始文件在 AWS S3。有人可以指出我需要如何在 Luigi Task 中设置它吗？

我查看了文档并找到了 luigi.S3 但我不清楚该怎么做，然后我在网上搜索并仅从 mortar-luigi 获取链接并在 luigi 顶部实现.

更新

遵循为@matagus 提供的示例（我也按照建议创建了 ~/.boto 文件）：

# coding: utf-8

import luigi

from luigi.s3 import S3Target, S3Client

class MyS3File(luigi.ExternalTask):
    def output(self):
        return S3Target('s3://my-bucket/19170205.txt')

class ProcessS3File(luigi.Task):

    def requieres(self):
        return MyS3File()

    def output(self):
        return luigi.LocalTarget('/tmp/resultado.txt')

    def run(self):
        result = None

        for input in self.input():
           print("Doing something ...")
           with input.open('r') as f:
               for line in f:
                   result = 'This is a line'

        if result:
            out_file = self.output().open('w')
            out_file.write(result)

当我执行它时没有任何反应

DEBUG: Checking if ProcessS3File() is complete
INFO: Informed scheduler that task   ProcessS3File()   has status   PENDING
INFO: Done scheduling tasks
INFO: Running Worker with 1 processes
DEBUG: Asking scheduler for work...
DEBUG: Pending tasks: 1
INFO: [pid 21171] Worker Worker(salt=226574718, workers=1, host=heliodromus, username=nanounanue, pid=21171) running   ProcessS3File()
INFO: [pid 21171] Worker Worker(salt=226574718, workers=1, host=heliodromus, username=nanounanue, pid=21171) done      ProcessS3File()
DEBUG: 1 running tasks, waiting for next task to finish
INFO: Informed scheduler that task   ProcessS3File()   has status   DONE
DEBUG: Asking scheduler for work...
INFO: Done
INFO: There are no more tasks to run at this time
INFO: Worker Worker(salt=226574718, workers=1, host=heliodromus, username=nanounanue, pid=21171) was stopped. Shutting down Keep-Alive thread

如您所见，Doing something... 消息从未打印出来。怎么了？

Answer 1

这里的关键是定义一个外部任务，它没有输入，输出是您在 S3 中已有的文件。 Luigi 文档在 Requiring another Task 中提到了这一点：

Note that requires() can not return a Target object. If you have a simple Target object that is created externally you can wrap it in a Task class

所以，基本上你最终会得到这样的结果：

import luigi

from luigi.s3 import S3Target

from somewhere import do_something_with


class MyS3File(luigi.ExternalTask):

    def output(self):
        return luigi.S3Target('s3://my-bucket/path/to/file')

class ProcessS3File(luigi.Task):

    def requires(self):
        return MyS3File()

    def output(self):
        return luigi.S3Target('s3://my-bucket/path/to/output-file')

    def run(self):
        result = None
        # this will return a file stream that reads the file from your aws s3 bucket
        with self.input().open('r') as f:
            result = do_something_with(f)

        # and the you 
        out_file = self.output().open('w')
        # it'd better to serialize this result before writing it to a file, but this is a pretty simple example
        out_file.write(result)

更新：

路易吉使用 boto to read files from and/or write them to AWS S3, so in order to make this code work, you'll need to provide your credentials in your boto config file ~/boto (look for other possible config file locations here):

[Credentials]
aws_access_key_id = <your_access_key_here>
aws_secret_access_key = <your_secret_key_here>

从 S3 开始的 Luigi Pipeline

Luigi Pipeline beginning in S3

python

amazon-s3

luigi