73 lines
3.2 KiB
Plaintext
Executable File
73 lines
3.2 KiB
Plaintext
Executable File
Perlbal Classes -- a brief introduction/overview.
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Socket -- descends from Danga::Socket
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Adds on to the base class to provide some functionality specifically
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useful for creating HTTP sockets.
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TCPListener -- descends from Perlbal::Socket
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Very lightweight and fast connection accept class. Takes incoming
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connections as fast as possible and passes them off, instantiating one of
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the various Client* classes to handle it.
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BackendHTTP -- descends from Perlbal::Socket
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This class handles connections to the backend web nodes for getting data
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back to the user. This class is used by other classes such as ClientProxy
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to send a request to an internal node.
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HTTPHeaders --
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Header management. Parses headers (request and response) and stores data
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for further user. Also manages validation of the request line so that it
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conforms to HTTP specifications.
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ClientHTTPBase -- descends from Perlbal::Socket
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Provides base functionality to ClientHTTP and ClientProxy. Notably, the
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ability to efficiently send files to the remote user. Also handles most of
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the state logic for statistics and such.
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ClientHTTP -- descends from Perlbal::ClientHTTPBase
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Very simple and lightweight class. Handles sending files to the user
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without much overhead. Most of the functionality is contained in the parent
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class, and this class doesn't implement much new stuff.
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ClientProxy -- descends from Perlbal::ClientHTTPBase
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Takes an incoming connection from a user and connects to a backend node
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(BackendHTTP) and relays the request. The backend can then either tell the
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proxy to reproxy and load a file from disk, or return a file directly, or
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just return a status message.
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ClientManage -- descends from Perlbal::Socket
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Simple interface that provides a way for users to use the management
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interface of Perlbal. You can connect to the management port (as defined
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in the config file) with a web browser or regular telnet.
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Service --
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A service is a particular item that Perlbal is doing. Services can have
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a role which defines how they behave. Each service can also have a bunch
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of parameters set to further adjust its behavior. By itself, the Service
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class handles maintaining pools of backend connections and managing statistics
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about itself.
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StatsListener -- descends from Perlbal::Socket
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This class listens for UDP broadcasts from the web nodes describing how
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many available children they have. This information is then used to pick an
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endpoint for a backend connection to be made to in order to handle a user's
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incoming request.
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{{ INTERNET }}
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v
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[Service]<===>[TCPListener]
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___/ | \___
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v v v
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[ClientManage] [ClientHTTP] [ClientProxy]
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^
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v
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[BackendHTTP]
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So connections come in from wherever and get to the TCPListener. It uses
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Service objects to determine what kind of Client* to spawn. The Client
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classes then handle crafting the response for the user.
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