python - Flask应用上下文

Question

在flask应用中，使用了threadPool模块，需要异步执行一些任务，这个任务主要是用于更新java代码后编译打包，耗时较长，也不想在应用中加入celery或redis异步执行，所以放在了threadpool里执行。

报错如下:

application not registered on db instance and no application bound to current context

在视图函数中

@main.route('/<branch>/<project_name>/update',methods = ['POST'])
def update_code(branch,project_name):
    version = request.form.get('version','last')
    db_url = db.session.query(svn_branch).filter_by(branch_name=branch).first()
    url = db_url.branch_url
    if url.endswith('/'):
        project_url = url + project_name
    else:
        project_url = url + '/' + project_name
    if version == 'last':
        cmd = ['svn','--non-interactive','--username',current_app.config['SVN_USER'],
            '--password',current_app.config['SVN_PASSWORD'],'info','--xml']
        cmd += [project_url]
        p = subprocess.Popen(cmd,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT)
        stdout = p.stdout.read()
        r = p.wait()
        if r != 0:
            return jsonify(code=500,
                           data='获取最新版本号失败')
        else:
            root = xml.etree.ElementTree.fromstring(stdout)
            list_ = root.findall('entry/commit')
            revision = list_[0].get('revision')
            print revision
            try:
                int(revision)
            except ValueError:
                return jsonify(code=500,
                               data='获取的最新版本号存在异常')
            version = revision
    data={
        'branch':branch,
        'project':project_name,
        'svn_path':project_url,
        'version':version,
        'jid':taskJid(),
        'source_code_dir':os.path.join(current_app.config['CODE_DIR'],project_name),
    }
    current_app.ThreadPool.apply_async(taskFunction)
    return jsonify(data=data)

taskFunction是来执行的函数，需要在任务开始前插入任务，设置为运行状态，在执行成功或者失败的后要修改任务状态，但是问题也就出来这里了，也自己尝试了解决但还未找到解决方法....
taskFunction函数执行任务

def taskFunction(**kwargs):
    try:
        db.session.query(svn_branch).first()
    except Exception as e:
        print e.message

此时报错

application not registered on db instance and no application bound to current context

希望各位大神帮忙解决，看了文档跟程序上下文有关，但还是未找到解决方法....

Answer 1

I think the context should be suppressed, so taskFunction should be modified to

def taskFunction(**kwargs):
    ctx = main.app_context()
    try:
        ctx.push()
        db.session.query(svn_branch).first()
    except Exception as e:
        print e.message
    finally:
        ctx.pop()
        

Answer 2

Can’t let it sink. . .