Gunicorn在使用WSGI时失败

Question

我想让Gunicorn通过WSGI与TileStache对话。但是当我运行这个命令时..。

gunicorn "TileStache:WSGITileServer('/var/osm/bright/project/OSMBright4/tilestache.cfg')"

...I获取以下错误：

2013-03-30 23:02:41 [14300] [INFO] Starting gunicorn 0.17.2
2013-03-30 23:02:41 [14300] [INFO] Listening at: http://127.0.0.1:8000 (14300)
2013-03-30 23:02:41 [14300] [INFO] Using worker: sync
2013-03-30 23:02:41 [14305] [INFO] Booting worker with pid: 14305
Error loading Tilestache config:
2013-03-30 23:02:41 [14305] [ERROR] Exception in worker process:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/arbiter.py", line 485, in spawn_worker
    worker.init_process()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/workers/base.py", line 100, in init_process
    self.wsgi = self.app.wsgi()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/app/base.py", line 103, in wsgi
    self.callable = self.load()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/app/wsgiapp.py", line 25, in load
    return util.import_app(self.app_uri)
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/util.py", line 381, in import_app
    app = eval(obj, mod.__dict__)
  File "<string>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/TileStache/__init__.py", line 373, in __init__
    self.config = parseConfigfile(config)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/__init__.py", line 166, in parseConfigfile
    return Config.buildConfiguration(config_dict, dirpath)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Config.py", line 217, in buildConfiguration
    config.layers[name] = _parseConfigfileLayer(layer_dict, config, dirpath)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Config.py", line 441, in _parseConfigfileLayer
    layer.provider = _class(layer, **provider_kwargs)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Mapnik.py", line 81, in __init__
    engine = mapnik.FontEngine.instance()
NameError: global name 'mapnik' is not defined
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/arbiter.py", line 485, in spawn_worker
    worker.init_process()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/workers/base.py", line 100, in init_process
    self.wsgi = self.app.wsgi()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/app/base.py", line 103, in wsgi
    self.callable = self.load()
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/app/wsgiapp.py", line 25, in load
    return util.import_app(self.app_uri)
  File "/usr/local/lib/python2.7/dist-packages/gunicorn/util.py", line 381, in import_app
    app = eval(obj, mod.__dict__)
  File "<string>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/TileStache/__init__.py", line 373, in __init__
    self.config = parseConfigfile(config)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/__init__.py", line 166, in parseConfigfile
    return Config.buildConfiguration(config_dict, dirpath)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Config.py", line 217, in buildConfiguration
    config.layers[name] = _parseConfigfileLayer(layer_dict, config, dirpath)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Config.py", line 441, in _parseConfigfileLayer
    layer.provider = _class(layer, **provider_kwargs)
  File "/usr/local/lib/python2.7/dist-packages/TileStache/Mapnik.py", line 81, in __init__
    engine = mapnik.FontEngine.instance()
NameError: global name 'mapnik' is not defined
2013-03-30 23:02:41 [14305] [INFO] Worker exiting (pid: 14305)
2013-03-30 23:02:41 [14300] [INFO] Shutting down: Master
2013-03-30 23:02:41 [14300] [INFO] Reason: Worker failed to boot.

有人知道这是什么意思吗？

Answer 1

问题已解决。

正如卡梅尔提到的，问题出在Mapnik和TileStache，而不是Gunicorn。

经过一些研究，我发现在不同的版本中都有changes of the python module name；它一直是mapnik，直到2.0版变成了mapnik2，然后又回到了2.1版的mapnik。显然，我似乎安装了2.0版。

我想我可以在TileStache/mapnik.py中改为import mapnik2，但我认为卸载Mapnik再卸载build it from source会更友好。这花了一段时间，但绝对值得。

非常感谢Karmel让我走上了正确的道路！

Answer 2

你安装了python-mapnik吗？错误似乎出现在TileStache和mapnik的配置中，而不是gunicorn或WSGI。如果您查看TileStache/Mapknik.py (我在这里查找：https://github.com/migurski/TileStache/blob/master/TileStache/Mapnik.py)，您会看到mapnik的初始导入传递了错误：

try:
    import mapnik
except ImportError:
    # can still build documentation
    pass

但是，当mapnik被期望出现在那里时，这将在第81行产生问题。因此，请确保apt-get安装了python-mapnik或确保mapnik在您的Python路径中。