带有魔杖的Google云功能停止工作 [英] Google cloud function with wand stopped working

问题描述

我已经设置了3个Google Cloud Storge存储桶和3个功能(每个存储桶一个)，这些功能会在将PDF文件上传到存储桶时触发.函数将PDF转换为png图像并进行进一步处理.

I have set up 3 Google Cloud Storge buckets and 3 functions (one for each bucket) that will trigger when a PDF file is uploaded to a bucket. Functions convert PDF to png image and do further processing.

当我尝试创建第四个存储桶和类似功能时，奇怪的是它不起作用.即使我复制了现有的三个功能之一，它仍然无法正常工作，并且出现了此错误:

When I am trying to create a 4th bucket and similar function, strangely it is not working. Even if I copy one of the existing 3 functions, it is still not working and I am getting this error:

Traceback (most recent call last): File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 333, in run_background_function _function_handler.invoke_user_function(event_object) File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 199, in invoke_user_function return call_user_function(request_or_event) File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 196, in call_user_function event_context.Context(**request_or_event.context)) File "/user_code/main.py", line 27, in pdf_to_img with Image(filename=tmp_pdf, resolution=300) as image: File "/env/local/lib/python3.7/site-packages/wand/image.py", line 2874, in __init__ self.read(filename=filename, resolution=resolution) File "/env/local/lib/python3.7/site-packages/wand/image.py", line 2952, in read self.raise_exception() File "/env/local/lib/python3.7/site-packages/wand/resource.py", line 222, in raise_exception raise e wand.exceptions.PolicyError: not authorized/tmp/tmphm3hiezy'@ error/constitute.c/ReadImage/412`

Traceback (most recent call last): File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 333, in run_background_function _function_handler.invoke_user_function(event_object) File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 199, in invoke_user_function return call_user_function(request_or_event) File "/env/local/lib/python3.7/site-packages/google/cloud/functions_v1beta2/worker.py", line 196, in call_user_function event_context.Context(**request_or_event.context)) File "/user_code/main.py", line 27, in pdf_to_img with Image(filename=tmp_pdf, resolution=300) as image: File "/env/local/lib/python3.7/site-packages/wand/image.py", line 2874, in __init__ self.read(filename=filename, resolution=resolution) File "/env/local/lib/python3.7/site-packages/wand/image.py", line 2952, in read self.raise_exception() File "/env/local/lib/python3.7/site-packages/wand/resource.py", line 222, in raise_exception raise e wand.exceptions.PolicyError: not authorized/tmp/tmphm3hiezy' @ error/constitute.c/ReadImage/412`

令我困惑的是为什么相同的功能可以在现有存储桶上运行，而不能在新存储桶上运行.

It is baffling me why same functions are working on existing buckets but not on new one.

更新: 即使这样也不起作用(出现缓存资源用尽"错误):

UPDATE: Even this is not working (getting "cache resources exhausted" error):

在requirements.txt中:

google-cloud-storage
wand

在main.py中:

import tempfile

from google.cloud import storage
from wand.image import Image

storage_client = storage.Client()

def pdf_to_img(data, context):
    file_data = data
    pdf = file_data['name']

    if pdf.startswith('v-'):
        return 

    bucket_name = file_data['bucket']

    blob = storage_client.bucket(bucket_name).get_blob(pdf)

    _, tmp_pdf = tempfile.mkstemp()
    _, tmp_png = tempfile.mkstemp()

    tmp_png = tmp_png+".png"

    blob.download_to_filename(tmp_pdf)
    with Image(filename=tmp_pdf) as image:
        image.save(filename=tmp_png)

    print("Image created")
    new_file_name = "v-"+pdf.split('.')[0]+".png"
    blob.bucket.blob(new_file_name).upload_from_filename(tmp_png)

上面的代码应该只是创建图像文件的副本，然后将其上传到存储桶中.

Above code is supposed to just create a copy of image file which is uploaded to bucket.

推荐答案

由于该漏洞已在Ghostscript中修复，但未在ImageMagick中更新，因此在Google Cloud Functions中将PDF转换为图像的解决方法是使用此 ghostscript包装器，并直接请求从Ghostscript将PDF转换为png(绕过ImageMagick).

Because the vulnerability has been fixed in Ghostscript but not updated in ImageMagick, the workaround for converting PDFs to images in Google Cloud Functions is to use this ghostscript wrapper and directly request the PDF conversion to png from Ghostscript (bypassing ImageMagick).

requirements.txt

google-cloud-storage
ghostscript==0.6

main.py

import locale
import tempfile
import ghostscript

from google.cloud import storage

storage_client = storage.Client()

def pdf_to_img(data, context):
    file_data = data
    pdf = file_data['name']

    if pdf.startswith('v-'):
        return 

    bucket_name = file_data['bucket']

    blob = storage_client.bucket(bucket_name).get_blob(pdf)

    _, tmp_pdf = tempfile.mkstemp()
    _, tmp_png = tempfile.mkstemp()

    tmp_png = tmp_png+".png"

    blob.download_to_filename(tmp_pdf)

    # create a temp folder based on temp_local_filename
    # use ghostscript to export the pdf into pages as pngs in the temp dir
    args = [
        "pdf2png", # actual value doesn't matter
        "-dSAFER",
        "-sDEVICE=pngalpha",
        "-o", tmp_png,
        "-r300", tmp_pdf
        ]
    # the above arguments have to be bytes, encode them
    encoding = locale.getpreferredencoding()
    args = [a.encode(encoding) for a in args]
    #run the request through ghostscript
    ghostscript.Ghostscript(*args)

    print("Image created")
    new_file_name = "v-"+pdf.split('.')[0]+".png"
    blob.bucket.blob(new_file_name).upload_from_filename(tmp_png)

无论如何，这可以使您解决问题，并将所有处理保留在GCF中.希望能帮助到你.但是，您的代码适用于单页PDF.我的用例是用于多页pdf转换，ghostscript代码& 此问题中的解决方案.

Anyway, this gets you around the issue and keeps all the processing in GCF for you. Hope it helps. Your code works for single page PDFs though. My use-case was for multipage pdf conversion, ghostscript code & solution in this question.

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