当使用Lambda和S3将数据插入到bucket时，AWS客户端错误。

Question

我试图使用lambda将json blob放入S3 bucket中，但在查看cloudwatch日志时，我得到了以下错误信息。

[ERROR] ClientError: An error occurred (AccessDenied) when calling the PutObject operation: Access Denied
Traceback (most recent call last):
  File "/var/task/main.py", line 147, in lambda_handler
    save_articles_and_comments(sub, submissions)
  File "/var/task/main.py", line 125, in save_articles_and_comments
    object.put(Body=json.dumps(articles))
  File "/var/task/boto3/resources/factory.py", line 520, in do_action
    response = action(self, *args, **kwargs)
  File "/var/task/boto3/resources/action.py", line 83, in __call__
    response = getattr(parent.meta.client, operation_name)(*args, **params)
  File "/var/task/botocore/client.py", line 316, in _api_call
    return self._make_api_call(operation_name, kwargs)
  File "/var/task/botocore/client.py", line 635, in _make_api_call
    raise error_class(parsed_response, operation_name)

所有的块公共访问设置都被设置为 "关闭"，代码中的 bucket 名称与 S3 中的相同。这是将json blob放入S3 bucket和lambda处理程序的代码。

def save_articles_and_comments(sub, submissions):
    """
    """
    s3 = boto3.resource('s3')
    now = dt.datetime.utcnow()
    formatted_date = now.strftime("%Y-%m-%d-%H-%M-%S")

    articles, comments = data_for_subreddit(submissions)
    print("Number of articles, comments {}, {}".format(len(articles), len(comments)))
    articles_name = 'articles/' + formatted_date + '_' + sub + '_articles.json'
    comments_name = 'comments/' + formatted_date + '_' + sub + '_comments.json'
    object = s3.Object('diegos-reddit-bucket', articles_name)
    object.put(Body=json.dumps(articles))
    print("Finished writing articles to {}".format(articles_name))

    object = s3.Object('diegos-reddit-bucket', comments_name)
    object.put(Body=json.dumps(comments))
    print("Finished writing comments to {}".format(comments_name))


def lambda_handler(x, y):
    """
    """
    import time
    import random
    idx = random.randint(0, len(SUBREDDITS)-1)
    start = time.time()
    assert PRAW_KEY is not None
    sub = SUBREDDITS[idx]
    red = reddit_instance()
    subreddit = red.subreddit(sub)

    print("Pulling posts from {}, {}.".format(sub, "hot"))
    submissions = subreddit.hot()
    save_articles_and_comments(sub, submissions)
    print("="*50)

    print("Pulling posts from {}, {}.".format(sub, "new"))
    submissions = subreddit.new()
    save_articles_and_comments(sub, submissions)
    print("="*50)

    print("Pulling posts from {}, {}.".format(sub, "top"))
    submissions = subreddit.top()
    save_articles_and_comments(sub, submissions)
    print("="*50)

    print("Pulling posts from {}, {}.".format(sub, "rising"))
    submissions = subreddit.rising()
    save_articles_and_comments(sub, submissions)
    end = time.time()
    print("Elapsed time {}".format(end - start))

我不知道代码中的问题是什么，所以才会出现上述错误，我把我的lambda_handler函数换成了main，在本地测试。有了main，它就能正常工作，并写入S3 bucket和它所尊重的文件夹。当我尝试通过AWS Lambda运行时，在函数完成从第一个subreddit拉取帖子并试图将json blob放入S3 bucket中的文件夹后，我得到了上述错误。这是我的输出应该是这样的

Pulling posts from StockMarket, hot.
Number of articles, comments 101, 909
Finished writing articles to articles/2020-06-03-02-48-44_StockMarket_articles.json
Finished writing comments to comments/2020-06-03-02-48-44_StockMarket_comments.json
==================================================
Pulling posts from StockMarket, new.
Number of articles, comments 101, 778
Finished writing articles to articles/2020-06-03-02-49-10_StockMarket_articles.json
Finished writing comments to comments/2020-06-03-02-49-10_StockMarket_comments.json
==================================================
Pulling posts from StockMarket, top.
Number of articles, comments 101, 5116
Finished writing articles to articles/2020-06-03-02-49-36_StockMarket_articles.json
Finished writing comments to comments/2020-06-03-02-49-36_StockMarket_comments.json
==================================================
Pulling posts from StockMarket, rising.
Number of articles, comments 24, 170
Finished writing articles to articles/2020-06-03-02-52-10_StockMarket_articles.json
Finished writing comments to comments/2020-06-03-02-52-10_StockMarket_comments.json
Elapsed time 215.6588649749756

是我的代码有问题，还是AWS方面的问题？

Answer 1

出现问题的原因是您有 无权限 将对象写入桶中。

PutObject 操作。拒绝访问

要想纠正这个问题，得看看以下几点 兰姆达执行角色：它是否有权限写入S3？也可以检查桶策略。

主它工作，并写入S3 bucket及其尊重的文件夹。当我尝试并通过AWS Lambda运行时，我得到了上述错误信息

当你在本地测试时，你的代码使用的是 自己的权限 (你的IAM用户)写到S3。这样就可以了。当你在lambda上执行代码时，你的函数不使用你的权限。相反，它使用定义在 兰姆达执行角色.