Dispatcher: httpdispatch

httpdispatch is the standalone dispatcher that starts the Genero Application Server (GAS) in command line. No web server is needed.

Important: The standalone GAS is for development only; provided to simplify your development setup and configuration. For deployment and production systems, you must include a Web server.

The GAS is configured through the GAS configuration file (as.xcf). This configuration file can be the default configuration file ($FGLASDIR/etc/as.xcf) or a custom configuration file that is specified when the Genero Application Server is started.

The standalone dispatcher can be started at the command line using the following command: 
httpdispatch
Alternatively, on Linux®/UNIX™ if using the GAS systemd service, you can execute the following command:
systemctl start httpdispatch.service

Syntax

httpdispatch [options [...]] [@argfile]
  1. options can be an option as described in Table 1.
  2. argfile defines a file that contains a list of override (-E) commands. The options file must use the following format:
    option-name 
option-value
[...]
    For examples, go to Set override options in a file.

Options

Table 1. httpdispatch options
Option Description

-h

--help

 Displays help information.

-p directory

--as-directory directory

 Specify the Genero Application Server directory.

-f configuration_file

--configuration-file configuration_file

 Specify which configuration file to use when starting the Genero Application Server dispatcher. If not specified, the default configuration file, $FGLASDIR/etc/as.xcf, is used.

-k

--no-keep-alive

 Disable keep alive for HTTP connections. For debug purpose only.

-E name=value

--resource-overwrite name=value

Overwrites the resource defined in the configuration file or creates a new one.

Example:

httpdispatch
 -E res.dvm.wa=$FGLDIR/bin/myrun

If in the configuration file "res.dvm.wa" has another value it is now set to myrun. The final value is the one set in the option.

-V

--version

 Displays version information.
--pid-file filename Write the dispatcher process-id to the specified file. The file is created. If the file exists, it is overwritten.
--dump-command Verify the dispatcher start-up commands by outputting them to standard out.
--keep-alive-timeout seconds Specify the time in seconds the dispatcher will wait for a subsequent HTTP request before closing the connection with the client. Once a request has been received, the timeout value applies. By default the keep-alive-timeout is 15 seconds.

What does "address already in use" mean ?

The message "address already in use" means that an application server (dispatcher) has already been started on the same port. Check the GAS configuration file (default $FGLASDIR/etc/as.xcf ) to identify the port where the application server (dispatcher) started. The port number is identified in the following section:
<INTERFACE_TO_CONNECTOR>
  <TCP_BASE_PORT>6300</TCP_BASE_PORT>
  <TCP_PORT_OFFSET>94</TCP_PORT_OFFSET>
    ...
</INTERFACE_TO_CONNECTOR>

The default port specified is 6394 - derived by adding the base port (6300) to the port offset (94). Set the values to a port which is not used by another application, see INTERFACE_TO_CONNECTOR.

Restarting the standalone GAS

To restart httpdispatch, use:
kill -9

Once the web server restarts the dispatcher, the dispatcher uses the session table to reconnect to the various proxies. The applications maintained by proxies, are still running, and once the dispatcher is relaunched, the user can continue his or her work.

Pressing CTRL-C or sending SIGTERM will stop the standalone dispatcher, and in both cases the dispatcher will request all proxies to stop. With kill -9 the dispatcher process is killed yet the sessions remain alive and untouched. When the dispatcher is restarted, the sessions continue to be active. Notice, the fastcgi dispatcher will stop sessions on pressing CTRL-C too if started in standalone mode. But not on SIGTERM.