Azure Web App部署的CodeIgniter应用文件夹写入权限问题求助

Let's work through this permission issue step by step—Azure Web App has some unique filesystem behaviors that can trip up traditional permission commands:

• First, confirm your target directory actually exists
  Sometimes this error pops up not just from permissions, but if the temp folder wasn't deployed or created properly. Head to Kudu (Advanced Tools > Go) and open the bash/cmd prompt:

  • For Linux: Run ls -l /home/site/wwwroot/assets/uploads/ to check if temp is present. If missing, create it with mkdir -p /home/site/wwwroot/assets/uploads/temp.
  • For Windows: Run dir D:\home\site\wwwroot\assets\uploads\ to verify, and create it with mkdir D:\home\site\wwwroot\assets\uploads\temp if needed.

• Set OS-specific permissions the right way
  Azure Web App runs under a dedicated service user, so generic chmod/attrib commands often don't work as expected:

  • Linux App Service: Your app runs as the www-data user. Run these commands in Kudu Bash to set recursive ownership and permissions:

    chown -R www-data:www-data /home/site/wwwroot/assets/uploads/temp
    chmod -R 755 /home/site/wwwroot/assets/uploads/temp
    

    This ensures the web server owns the directory and has full write access.
  • Windows App Service: Windows uses ACLs instead of Unix-style permissions. Run this in Kudu CMD to grant the app pool user recursive read/write access:

    icacls "D:\home\site\wwwroot\assets\uploads\temp" /grant "IIS AppPool\DefaultAppPool":(OI)(CI)RW /T
    

    The (OI)(CI) flags apply permissions to all subfolders/files, and /T makes the change recursive.

• Double-check CodeIgniter's upload path config
  Avoid relative paths in your config/upload.php—they can resolve incorrectly in Azure's environment. Use CodeIgniter's built-in FCPATH constant (points to your app's root folder):

  $config['upload_path'] = FCPATH . 'assets/uploads/temp/';
  

  A tiny typo here can cause the same "not writable" error, so verify the folder name matches exactly.

• Compare staging vs production configurations
  Since staging works, use Kudu on the staging slot to reverse-engineer the working setup:

  • On Linux: Run ls -l /home/site/wwwroot/assets/uploads/temp to check owner and permissions.
  • On Windows: Run icacls D:\home\site\wwwroot\assets\uploads\temp to view ACL settings.
    Replicate those exact permissions in production. You can also check Azure Portal > App Service > Deployment Slots > Staging > Configuration to see if any app settings (like WEBSITE_LOCAL_CACHE_OPTION) affect filesystem access.

• Troubleshoot local cache interference
  If your app has local cache enabled, permission changes might not take effect immediately. Check Azure Portal > App Service > Configuration > Application Settings for WEBSITE_LOCAL_CACHE_OPTION. If set to Always, temporarily switch it to Never, restart the app service, apply your permission changes, then switch it back if needed.

• Quick test to isolate code vs filesystem issues
  To rule out CodeIgniter code problems, temporarily set the upload path to Azure's default temp directory:

  • Linux: $config['upload_path'] = '/tmp/';
  • Windows: $config['upload_path'] = 'D:\local\Temp\';
    If uploads work here, the issue is definitely with your assets/uploads/temp folder's permissions, not your code.

内容的提问来源于stack exchange，提问作者user1400290