.. _flup: http://trac.saddi.com/flup .. _gae: http://code.google.com/appengine/docs/python/overview.html .. _wsgiref: http://docs.python.org/library/wsgiref.html .. _cherrypy: http://www.cherrypy.org/ .. _paste: http://pythonpaste.org/ .. _rocket: http://pypi.python.org/pypi/rocket .. _gunicorn: http://pypi.python.org/pypi/gunicorn .. _fapws3: http://www.fapws.org/ .. _tornado: http://www.tornadoweb.org/ .. _twisted: http://twistedmatrix.com/ .. _diesel: http://dieselweb.org/ .. _meinheld: http://pypi.python.org/pypi/meinheld .. _bjoern: http://pypi.python.org/pypi/bjoern .. _gevent: http://www.gevent.org/ .. _eventlet: http://eventlet.net/ .. _waitress: http://readthedocs.org/docs/waitress/en/latest/ .. _apache: http://httpd.apache.org/ .. _mod_wsgi: http://code.google.com/p/modwsgi/ .. _pound: http://www.apsis.ch/pound .. _tutorial-deployment: ================================================================================ Deployment ================================================================================ The bottle :func:`run` function, when called without any parameters, starts a local development server on port 8080. You can access and test your application via http://localhost:8080/ if you are on the same host. To get your application available to the outside world, specify the IP of the interface the server should listen to (e.g. ``run(host='192.168.0.1')``) or let the server listen to all interfaces at once (e.g. ``run(host='0.0.0.0')``). The listening port can be changed in a similar way, but you need root or admin rights to choose a port below 1024. Port 80 is the standard for HTTP servers:: run(host='0.0.0.0', port=80) # Listen to HTTP requests on all interfaces Server Options ================================================================================ The built-in default server is based on `wsgiref WSGIServer `_. This non-threading HTTP server is perfectly fine for development and early production, but may become a performance bottleneck when server load increases. There are three ways to eliminate this bottleneck: * Use a different server that is either multi-threaded or asynchronous. * Start multiple server processes and spread the load with a load-balancer. * Do both. **Multi-threaded** servers are the 'classic' way to do it. They are very robust, reasonably fast and easy to manage. As a drawback, they can only handle a limited number of connections at the same time and utilize only one CPU core due to the "Global Interpreter Lock" (GIL). This does not hurt most applications, they are waiting for network IO most of the time anyway, but may slow down CPU intensive tasks (e.g. image processing). **Asynchronous** servers are very fast, can handle a virtually unlimited number of concurrent connections and are easy to manage, but can get a bit tricky. To take full advantage of their potential, you need to design your application accordingly and understand the concepts of the specific server. **Multi-processing** (forking) servers are not limited by the GIL and utilize more than one CPU core, but make communication between server instances more expensive. You need a database or external message query to share state between processes, or design your application so that it does not need any shared state. The setup is also a bit more complicated, but there are good tutorials available. Switching the Server Backend ================================================================================ The easiest way to increase performance is to install a multi-threaded server library like paste_ or cherrypy_ and tell Bottle to use that instead of the single-threaded server:: bottle.run(server='paste') Bottle ships with a lot of ready-to-use adapters for the most common WSGI servers and automates the setup process. Here is an incomplete list: ======== ============ ====================================================== Name Homepage Description ======== ============ ====================================================== cgi Run as CGI script flup flup_ Run as FastCGI process gae gae_ Helper for Google App Engine deployments wsgiref wsgiref_ Single-threaded default server cherrypy cherrypy_ Multi-threaded and very stable paste paste_ Multi-threaded, stable, tried and tested rocket rocket_ Multi-threaded waitress waitress_ Multi-threaded, poweres Pyramid gunicorn gunicorn_ Pre-forked, partly written in C eventlet eventlet_ Asynchronous framework with WSGI support. gevent gevent_ Asynchronous (greenlets) diesel diesel_ Asynchronous (greenlets) fapws3 fapws3_ Asynchronous (network side only), written in C tornado tornado_ Asynchronous, powers some parts of Facebook twisted twisted_ Asynchronous, well tested but... twisted meinheld meinheld_ Asynchronous, partly written in C bjoern bjoern_ Asynchronous, very fast and written in C auto Automatically selects an available server adapter ======== ============ ====================================================== The full list is available through :data:`server_names`. If there is no adapter for your favorite server or if you need more control over the server setup, you may want to start the server manually. Refer to the server documentation on how to run WSGI applications. Here is an example for paste_:: application = bottle.default_app() from paste import httpserver httpserver.serve(application, host='0.0.0.0', port=80) Apache mod_wsgi -------------------------------------------------------------------------------- Instead of running your own HTTP server from within Bottle, you can attach Bottle applications to an `Apache server `_ using mod_wsgi_. All you need is an ``app.wsgi`` file that provides an ``application`` object. This object is used by mod_wsgi to start your application and should be a WSGI-compatible Python callable. File ``/var/www/yourapp/app.wsgi``:: # Change working directory so relative paths (and template lookup) work again os.chdir(os.path.dirname(__file__)) import bottle # ... build or import your bottle application here ... # Do NOT use bottle.run() with mod_wsgi application = bottle.default_app() The Apache configuration may look like this:: ServerName example.com WSGIDaemonProcess yourapp user=www-data group=www-data processes=1 threads=5 WSGIScriptAlias / /var/www/yourapp/app.wsgi WSGIProcessGroup yourapp WSGIApplicationGroup %{GLOBAL} Order deny,allow Allow from all Google AppEngine -------------------------------------------------------------------------------- .. versionadded:: 0.9 The ``gae`` server adapter is used to run applications on Google App Engine. It works similar to the ``cgi`` adapter in that it does not start a new HTTP server, but prepares and optimizes your application for Google App Engine and makes sure it conforms to their API:: bottle.run(server='gae') # No need for a host or port setting. It is always a good idea to let GAE serve static files directly. Here is example for a working ``app.yaml``:: application: myapp version: 1 runtime: python api_version: 1 handlers: - url: /static static_dir: static - url: /.* script: myapp.py Load Balancer (Manual Setup) -------------------------------------------------------------------------------- A single Python process can utilize only one CPU at a time, even if there are more CPU cores available. The trick is to balance the load between multiple independent Python processes to utilize all of your CPU cores. Instead of a single Bottle application server, you start one instance for each CPU core available using different local port (localhost:8080, 8081, 8082, ...). You can choose any server adapter you want, even asynchronous ones. Then a high performance load balancer acts as a reverse proxy and forwards each new requests to a random port, spreading the load between all available back-ends. This way you can use all of your CPU cores and even spread out the load between different physical servers. One of the fastest load balancers available is Pound_ but most common web servers have a proxy-module that can do the work just fine. Pound example:: ListenHTTP Address 0.0.0.0 Port 80 Service BackEnd Address 127.0.0.1 Port 8080 End BackEnd Address 127.0.0.1 Port 8081 End End End Apache example:: BalancerMember http://192.168.1.50:80 BalancerMember http://192.168.1.51:80 ProxyPass / balancer://mycluster Lighttpd example:: server.modules += ( "mod_proxy" ) proxy.server = ( "" => ( "wsgi1" => ( "host" => "127.0.0.1", "port" => 8080 ), "wsgi2" => ( "host" => "127.0.0.1", "port" => 8081 ) ) ) Good old CGI ================================================================================ A CGI server starts a new process for each request. This adds a lot of overhead but is sometimes the only option, especially on cheap hosting packages. The `cgi` server adapter does not actually start a CGI server, but transforms your bottle application into a valid CGI application:: bottle.run(server='cgi')