芹菜处理任务和修改模型字段

Question

我想使用ffmpeg和celery将视频转换为mp4进行异步任务。当用户上传视频时，该视频将用于original_video并保存。之后，我希望芹菜将其转换为mp4_720字段的不同版本。然而，我对如何使用芹菜应用该逻辑感到困惑。

app.models.py:

class Video(models.Model):
    title = models.CharField(max_length=75)
    pubdate = models.DateTimeField(default=timezone.now)
    original_video = models.FileField(upload_to=get_upload_file_name)
    mp4_720 = models.FileField(upload_to=get_upload_file_name, blank=True, null=True)
    converted = models.BooleanField(default=False)

app.views.py:

def upload_video(request):
    if request.POST:
        form = VideoForm(request.POST, request.FILES)
        if form.is_valid():
            video = form.save(commit=False)
            video.save()
            // Celery to convert the video
            convert_video.delay(video)
            return HttpResponseRedirect('/')
    else:
        form = VideoForm()
    return render(request, 'upload_video.html', {
        'form':form
    })

app.tasks.py:

@app.task
def convert_video(video):
    // Convert the original video into required format and save it in the mp4_720 field using the following command:
    //subprocess.call('ffmpeg -i (path of the original_video) (video for mp4_720)')
    // Change the converted boolean field to True
    // Save

基本上我的问题是如何保存转换后的视频在mp4_720。非常感谢您的帮助和指导。谢谢你。

** update **

我想让这个方法做的是首先转换视频。然后将转换后的视频保存在video.mp4_720字段中。如果所有操作都正确，请更改视频。转换为True。我如何定义方法来实现这个功能?

Answer 1

首先，您可能不希望将video对象传递给芹菜—详细信息请参见这个问题。

你可以这样命名它:

        convert_video.delay(video.id)

和

logger = logging.getLogger(__name__)  # assuming you have set up logging elsewhere
@app.task
def convert_video(video_id):
    video = Video.objects.get(video_id)
    cmd = ['ffmpeg',  '-i', video.original_video.path, video.mp4_720.path]
    log.info('running %s', ' '.join(cmd))
    proc = subprocess.Popen(cmd)
    proc.subprocess.wait()
    if p.returncode != 0:
        log.error('command failed with ret val %s', p.returncode)
        log.info(p.stderr)
        log.info(p.stdout)
    else:
        video.converted = True
        video.save()
        log.info('video converted ok')