//
// ============LICENSE_START=======================================================
//  Copyright (C) 2016-2018 Ericsson. All rights reserved.
// ================================================================================
// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE
// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode
// 
// SPDX-License-Identifier: CC-BY-4.0
// ============LICENSE_END=========================================================
//
// @author Sven van der Meer (sven.van.der.meer@ericsson.com)
//

== The APEX Engine
The APEX engine can be started in different ways, depending your requirements.
All scripts are located in the APEX __bin__ directory

On UNIX and Cygwin systems use:

- `apexEngine.sh` - this script will
  ** Test if `$APEX_USER` is set and if the user exists, terminate with an error otherwise
  ** Test if `$APEX_HOME` is set. If not set, it will use the default setting as `/opt/app/policy/apex-pdp/apex-pdp`.
     Then the set directory is tested to exist, the script will terminate if not.
  ** When all tests are passed successfully, the script will call `apexApps.sh` with arguments to start the APEX engine.
- `apexApps.sh engine` - this is the general APEX application launcher, which will
  ** Start the engine with the argument `engine`
  ** Test if `$APEX_HOME` is set and points to an existing directory. If not set or directory does not exist, script terminates.
  ** Not test for any settings of `$APEX_USER`.

On Windows systems use `apexEngine.bat` and `apexApps.bat engine` respectively.
Note: none of the windows batch files will test for `%APEX_USER%`.

Summary of alternatives to start the APEX Engine:

[width="100%",options="header",cols="5a,5a"]
|====================
| Unix, Cygwin | Windows
|
[source%nowrap,sh]
----
# $APEX_HOME/bin/apexEngine.sh [args]
# $APEX_HOME/bin/apexApps.sh engine [args]
----
|
[source%nowrap,bat]
----
> %APEX_HOME%\bin\apexEngine.bat [args]
> %APEX_HOME%\bin\apexApps.bat engine [args]
----
|====================


The APEX engine comes with a few CLI arguments for setting configuration and policy model.
The configuration file is always required.
The policy model file is only required if no model file is specified in the configuration, or if the specified model file should be over written.
The option `-h` prints a help screen.

[source%nowrap,sh]
----
usage: org.onap.policy.apex.service.engine.main.ApexMain [options...]
options
-c,--config-file <CONFIG_FILE>  the full path to the configuration file to use, the configuration file must be a Json file
                                containing the Apex configuration parameters
-h,--help                       outputs the usage of this command
-m,--model-file <MODEL_FILE>    the full path to the model file to use, if set it overrides the model file set in the
                                configuration file
-v,--version                    outputs the version of Apex
----