Starting and Stopping the Web Server
Starting and stopping the web server involves the following steps:
Normal Production Usage
The PicLan-IP software runs on a collections of MV processes. One of these
processes is the "supervisor" process and one or more processes are "thread"
processes. None of these processes are designed to accept terminal input
from the user. These processes do output informational messages to the
terminal (if one is connected) and also output these messages to a MV data
item that can be monitored to "watch" PicLan-IP activity. It is important
to remember that the activity that can be monitored only included messages
that PicLan-IP outputs intentionally. If a process aborts, exits to TCL,
or generates some other unanticipated system message, then you will not
see that message on the monitored output.
For this reason, if you are experiencing any trouble configuration
the PicLan-Ip software, you should run the PicLan-IP processes on "normal"
MV ports that have terminals (or network connections) on which you can
see the actual terminal output.
Run the command PLIP-START to log the web supervisor process on.
The web supervisor process will in turn log the web thread processes on.
The PLIP-START verb automatically runs the PLIP-MONITOR program
that will watch the activity of the PicLan processes as they begin. If
you wish to run PLIP-START without starting the monitor, include the (M
option on the PLIP-START verb.
If the web server is to be run on non-phantom Pick ports, make sure that
all configured ports are logged off.
If the web server is to be run on AP or Sequoia PRO phantom ports, make
sure that no ports are currently running web processes.
If you with to stop the web processing, run the command PLIP-STOP.
This command will signal the web supervisor process to log off and to signal
the web thread processes to log off. Stopping the web may take 20 seconds
(or longer) depending on what settings are used and whether any web thread
processes are busy at the time. When the web is stopped, all active requests
are closed without any error messages. Users will get "connection reset
by peer" in this case. The PLIP-STOP verb will also start the PLIP-MONITOR
command, but will exit back to TCL when the last helper process finishes.
Do not log the web processes off manually with the Pick LOGOFF verb.
To do so will leave TCP connections stranded requiring you to manually
Monitoring the Web Processes
The web processes (both supervisor and thread) generate information messages
to the screen and also write these messages into buffer area. This buffer
area allows you to "peek into" the running web server's processes using
the PLIP-MONITOR command. PLIP-MONITOR is actually automatically
started when you run PLIP-START unless you include the (M
option to supress this behaviour. The PLIP-MONITOR command will
display all of the supervisor and thread ports activity with the port number
at the left followed by the message at the right. The PLIP-MONITOR
program can catch up with at most 8K of outbound data without discarding
some of the output stream. Also, you can only run one PLIP-MONITOR
program at any time.
It is important to remember that PLIP-MONITOR will only display messages
that are "normal" and "intended" from the supervisor and thread processes.
If a process aborts, exits to TCL, or otherwise malfunctions in a manner
not logable by the process itself, then PLIP-MONITOR will not display such
Changing Web Configurations While Running
It is perfectly acceptable to change the PLIP.CTRL CONFIG
item while the web server is running. The web process threads check this
file every six seconds and will automatically reconfigure whenever it is
Also, if you change web configurations that need to invalidate Web Server
cache settings, you should execute CACHE-CLEAR to clear the cache files
so that new content is reflected. This is only necessary when your change
in contents is caused by a change in the web server's configuration file
and not because you changed the content itself.
Killing TCP Connection Control Blocks
If you have incorrectly stopped a web server thread process, then you may
need to manually kill the TCP connection control blocks with the PicLan
verb. Non-native hosts have a stripped-down version of PL-KILL
and PL-STAT included in the PICLAN-IP account.
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