EMEN2 control script (emen2ctl)

Similar to Apache's "apachectl" script, EMEN2 includes an "emen2ctl" script. This can be used to start and stop the server and perform some basic administration tasks.

Running emen2ctl

Note: Depending on how you installed EMEN2, emen2ctl may not be in your $PATH. On Linux, using the recommended installation, it will probably be $HOME/Python/bin/emen2ctl. You can either invoke the script using the full path, or add the directory to your path.

emen2ctl accepts a single command argument and options after that:

bash$ emen2ctl
Usage: /usr/local/bin/emen2ctl {start|stop|restart|recover} [options]

The following commands are defined:

start: Start the EMEN2 web server
stop: Stop the EMEN2 web server
restart: Restart the EMEN2 web server
recover: Run database recovery

emen2ctl also requires an EMEN2 database environment. This may be set using either the "-h" option (e.g. "-h $HOME/test.db") or by setting the $EMEN2DBHOME environment variable.

All emen2ctl options will be passed to the EMEN2 server. These will usually be used when starting the server: -e to load extensions, and --port to specify a port.

Note: In the future, the extensions to be loaded will be stored in the configuration file and editable using the web interface instead of the "-e" option. For now, specify them on the command line with "-e".

Start the EMEN2 web server

The "start" command will start the EMEN2 web server. In this example, we pass a database environment with "-h" and bind the server to port 8080 (default) with "--port".

bash$ emen2ctl start -h ~/test.db --port 8080
Starting emen2
[INFO] Web server started

This will create a "pid" file in the database environment (in this example, /Users/irees/test.db/log/emen2.pid). This file will be used to communicate with the server process later.

Stop the EMEN2 web server

Similarly, the "stop" command will attempt to gracefully stop the EMEN2 web server:

bash$ emen2ctl stop -h ~/test.db
Stopping emen2 [process 30821]

Restart the EMEN2 web server

Similar to "start." This will stop the current server process, then restart.

bash$ emen2ctl restart -h ~/test.db
Stopping emen2 [process 30821]
Starting emen2
Removing stale pidfile /Users/irees/test.db/log/emen2.pid
[INFO] Web server started

Run database recovery

If the server or EMEN2 crashes, you will want to run database recovery before restarting. This will clean the underlying Berkeley DB environment, and abort any transactions that were uncommitted.

bash$ emen2ctl recover -h ~/test.db
Running emen2 database recovery
BDB2526 Finding last valid log LSN: file: 1 offset 650860
BDB1514 Recovery starting from [1][622364]
BDB1518 Recovery complete at Mon Mar 12 05:14:18 2012
BDB1519 Maximum transaction ID 80000075 recovery checkpoint [1][653815]