TSHttpConnectPlugin

Allows the plugin to initiate an http connection. This will tag the HTTP state machine with extra data that can be accessed by the logging interface. Additional arguments provide buffer settings that are used when constructing IOBuffers. The connection is treated as an HTTP transaction as if it came from a client.

Synopsis

#include <ts/ts.h>

TSVConn TSHttpConnectPlugin(TSHttpConnectOptions *options)

Description

This call attempts to create an HTTP state machine and a virtual connection to that state machine. This is more efficient than using TSNetConnect() because it avoids using the operating system stack via the loopback interface.

options

A TSHttpConnectOptions structure that contains fields that provide the network address of the target, a tag that can be passed through to the HTTP state machine, a plugin ID, a buffer index and buffer water mark.

The virtual connection returned as the TSVConn is API equivalent to a network virtual connection both to the plugin and to internal mechanisms. Data is read and written to the connection (and thence to the target system) by reading and writing on this virtual connection.

Note

This function only opens the connection. To drive the transaction an actual HTTP request must be sent and the HTTP response handled. The transaction is handled as a standard HTTP transaction and all of the standard configuration options and plugins will operate on it.

The combination of tag and id is intended to enable correlation in log post processing. The tag identifies the connection as related to the plugin and the id can be used in conjunction with plugin generated logs to correlate the log records.

Notes

The H2 implementation uses this to correlate client sessions with H2 streams. Each client connection is assigned a distinct numeric identifier. This is passed in the options structure via the member variable id to the TSHttpConnectPlugin() function. The tag is selected to be the ALPN (or NPN) string for the client session protocol, e.g. “h2”. Log post processing can then count the number of connections for the various supported protocols and the number of H2 virtual streams for each real client connection to Traffic Server.

See Also

TSHttpConnectWithPluginId(3ts), TSHttpConnect(3ts), TSNetConnect(3ts), TSAPI(3ts)