Azure Functions导入python-tabular报错：找不到libmono

我有一个用于连接SSAS模型，执行分区创建、删除及刷新操作的脚本：分区操作使用pyadomd库，刷新操作使用python-tabular库（版本0.1.7）。将代码部署到Azure Functions后，触发函数时在import pytabular语句处报错，完整异常信息显示RuntimeError: Could not find libmono。请求协助解决该问题。

依赖清单（requirements.txt） #

azure-functions
python-tabular
pyadomd
msal
numpy
pandas
pymsteams
azure-storage-blob

核心代码片段 #

test_run.py #

import pytabular
from pyadomd import Pyadomd
# 其他导入语句略
def func_1():
   '''rest of the code here'''
   return df
def func_2(df1):
   '''rest of the code here'''
def main_func():
   try:
       df1 = func_1()
       func_2(df1)
   except Exception as e:
       '''some code logic to retry'''

init.py #

import azure.functions as func
import logging
import sys
import os
from .test_run import main_func

current_dir = os.path.dirname(os.path.abspath(__file__))
sys.path.append(os.path.join(current_dir))

def main(req: func.HttpRequest) -> func.HttpResponse:
    logging.info('Python HTTP trigger function processed a request.')
    try:
        main_func()
        # 请求处理逻辑略
    except Exception as e:
        return  func.HttpResponse(f"An error occurred: {str(e)}", status_code=500)

完整异常栈 #

Full Exception :
 Exception while executing function
 /Functions.httpTrigger ---> Microsoft.Azure.WebJobs.Script.Workers.Rpc.RpcException 
 /Result
 /Failure Exception
 /RuntimeError
 /Could not find libmono 

 /  
 '/azure-functions-host/workers/python/3.10/LINUX/X64/azure_functions_worker/dispatcher.py', line 380, in _handle__function_load_request     func = loader.load_function(   
 '/azure-functions-host/workers/python/3.10/LINUX/X64/azure_functions_worker/utils/wrappers.py', line 44, in call     return func(*args, **kwargs)   
 '/azure-functions-host/workers/python/3.10/LINUX/X64/azure_functions_worker/loader.py', line 132, in load_function     mod = importlib.import_module(fullmodname)   
 '/usr/local/lib/python3.10/importlib/__init__.py', line 126, in import_module     return _bootstrap._gcd_import(name[level:], package, level)   
 '<frozen importlib._bootstrap>', line 1050, in _gcd_import   
 '<frozen importlib._bootstrap>', line 1027, in _find_and_load   
 '<frozen importlib._bootstrap>', line 1006, in _find_and_load_unlocked   
 '<frozen importlib._bootstrap>', line 688, in _load_unlocked   
 '<frozen importlib._bootstrap_external>', line 883, in exec_module   
 '<frozen importlib._bootstrap>', line 241, in _call_with_frames_removed   
 '/home/site/wwwroot/httpTrigger/__init__.py', line 9, in <module>     from .refresh_automation import main_func   
 '/home/site/wwwroot/httpTrigger/refresh_automation.py', line 6, in <module>     import pytabular   
 '/home/site/wwwroot/.python_packages/lib/site-packages/pytabular/__init__.py', line 45, in <module>     import clr   
 '/home/site/wwwroot/.python_packages/lib/site-packages/clr.py', line 6, in <module>     load()   
 '/home/site/wwwroot/.python_packages/lib/site-packages/pythonnet/__init__.py', line 36, in load     set_default_runtime()   
 '/home/site/wwwroot/.python_packages/lib/site-packages/pythonnet/__init__.py', line 22, in set_default_runtime     set_runtime(clr_loader.get_mono())   
 '/home/site/wwwroot/.python_packages/lib/site-packages/clr_loader/__init__.py', line 21, in get_mono     libmono = find_libmono(sgen)   
 '/home/site/wwwroot/.python_packages/lib/site-packages/clr_loader/util/find.py', line 67, in find_libmono     raise RuntimeError('Could not find libmono')     
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Script.Description.WorkerFunctionInvoker.InvokeCore(Object[] parameters,FunctionInvocationContext context) 
/src/azure-functions-host/src/WebJobs.Script/Description/Workers/WorkerFunctionInvoker.cs 
 /101    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Script.Description.FunctionInvokerBase.Invoke(Object[] parameters) 
/src/azure-functions-host/src/WebJobs.Script/Description/FunctionInvokerBase.cs 
 /82    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Script.Description.FunctionGenerator.Coerce[T](Task`1 src) 
/src/azure-functions-host/src/WebJobs.Script/Description/FunctionGenerator.cs 
 /225    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker`2.InvokeAsync[TReflected,TReturnValue](Object instance,Object[] arguments) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionInvoker.cs 
 /52    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.InvokeWithTimeoutAsync(IFunctionInvoker invoker,ParameterHelper parameterHelper,CancellationTokenSource timeoutTokenSource,CancellationTokenSource functionCancellationTokenSource,Boolean throwOnTimeout,TimeSpan timerInterval,IFunctionInstance instance) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs 
 /581    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithWatchersAsync(IFunctionInstanceEx instance,ParameterHelper parameterHelper,ILogger logger,CancellationTokenSource functionCancellationTokenSource) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs 
 /527    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(IFunctionInstanceEx instance,FunctionStartedMessage message,FunctionInstanceLogEntry instanceLogEntry,ParameterHelper parameterHelper,ILogger logger,CancellationToken cancellationToken) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs 
 /306    End of inner exception    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(IFunctionInstanceEx instance,FunctionStartedMessage message,FunctionInstanceLogEntry instanceLogEntry,ParameterHelper parameterHelper,ILogger logger,CancellationToken cancellationToken) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs 
 /352    
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()    
async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.TryExecuteAsync(IFunctionInstance functionInstance,CancellationToken cancellationToken) 
D:\a\_work\1\s\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs 
 /108

解决方法 #

原因分析 #

python-tabular依赖pythonnet，而pythonnet在Linux环境下需要依赖Mono运行时。Azure Functions的Linux默认运行时没有预装Mono，因此会出现找不到libmono的错误。

方案1：使用自定义Docker镜像部署Azure Functions #

创建Dockerfile，基于Azure Functions Python基础镜像安装Mono：

FROM mcr.microsoft.com/azure-functions/python:4-python3.10

# 安装Mono运行时
RUN apt-get update && apt-get install -y mono-complete

ENV AzureWebJobsScriptRoot=/home/site/wwwroot \
    AzureFunctionsJobHost__Logging__Console__IsEnabled=true

COPY requirements.txt /
RUN pip install -r /requirements.txt

COPY . /home/site/wwwroot

构建镜像并推送到Azure Container Registry，然后配置Azure Functions使用该自定义镜像运行。

方案2：替换python-tabular为纯Python实现 #

python-tabular依赖.NET生态，在Linux环境部署受限。可以改用pyadomd执行XMLA脚本完成SSAS刷新操作，示例代码：

from pyadomd import Pyadomd

# 替换为你的SSAS连接字符串
connection_string = "Provider=MSOLAP;Data Source=your-ssas-server;Initial Catalog=your-model;User ID=your-user;Password=your-password;"

# 替换为目标分区的XMLA刷新脚本
xmla_refresh = """<Batch xmlns="http://schemas.microsoft.com/analysisservices/2003/engine">
    <Parallel>
        <Process xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <Object>
                <DatabaseID>your-model</DatabaseID>
                <CubeID>Model</CubeID>
                <MeasureGroupID>your-measure-group</MeasureGroupID>
                <PartitionID>your-partition</PartitionID>
            </Object>
            <Type>ProcessFull</Type>
            <WriteBackTableCreation>UseExisting</WriteBackTableCreation>
        </Process>
    </Parallel>
</Batch>"""

with Pyadomd(connection_string) as conn:
    with conn.cursor() as cur:
        cur.execute(xmla_refresh)

方案3：切换Azure Functions运行时为Windows #

Windows环境预装了.NET Framework，pythonnet可直接运行，不会出现libmono缺失问题。在Azure Functions配置页面，将运行时堆栈切换为Python + Windows即可。

内容的提问来源于stack exchange，提问作者Beginner