Starting the OPG4J Shell

Launching the OPG4J Shell

The Java shell executables are found in /opt/oracle/graph/bin after the graph server (PGX) installation, and in <CLIENT_INSTALL_DIR>/bin after the Java client installation.

The OPG4J shell uses JShell, which means the shell needs to run on Java 11 or later. See Installing the Java Client for more details on the prerequisites. You can then launch the OPG4J shell by entering the following in your terminal:

cd /opt/oracle/graph
./bin/opg4j

When the shell has started, the following command line prompt appears:

For an introduction type: /help intro
Oracle Graph Server Shell 21.4.0
Variables instance, session, and analyst ready to use.
opg4j>

By default, the OPG4J shell creates a local PGX instance, to run graph functions in the same JVM as the shell as described in Developing Applications Using Graph Server Functionality as a Library.

Command-line Options

To view the list of available command-line options, add --help to the opg4j command:

./bin/opg4j --help

To start the opg4j shell without connecting to the graph server (PGX), use the --no_connect option as shown:

./bin/opg4j --no_connect

Starting the OPG4J Shell on Remote Mode

The OPG4J shell can connect to a graph server (PGX) instance that is running on another JVM (possibly on a different machine). In order to launch the OPG4J shell in remote mode, you must specify the --base_url parameter as shown:

./bin/opg4j --base_url https://<host>:7007 --username <graphuser>

where :

<host>: is the server host
<graphuser>: is the database user
You will be prompted for the database password.

Note:

The graph server (PGX), listens on port 7007 by default. If needed, you can configure the graph server to listen on a different port by changing the port value in the server configuration file (server.conf). See Configuring the In-Memory Graph Server (PGX) for details.

When the shell has started, the following command line prompt appears:

Oracle Graph Server Shell 21.4.0
Variables instance, session, and analyst ready to use.
opg4j>

If you have multiple versions of Java installed, you can easily switch between installations by setting the JAVA_HOME variable before starting the shell. For example:

export JAVA_HOME=/usr/lib/jvm/java-11-oracle

Batch Execution of Scripts

The OPG4J shell can execute a script by passing the path(s) to the script(s) to the opg4j command. For example:

./bin/opg4j /path/to/script.jsh

Predefined Functions

The OPG4J shell provides the following utility functions:

println(String): A shorthand for System.out.println(String).
loglevel(String loggerName, String levelName): A convenient function to set the loglevel.

The loglevel function allows you to set the log level for a logger. For example, loglevel("ROOT", "INFO") sets the level of the root logger to INFO. This causes all logs of INFO and higher (WARN, ERROR, FATAL) to be printed to the console.

Script Arguments

You can also provide parameters to the script. For example:

./bin/opg4j /path/to/script.jsh script-arg-1 script-arg-2

In this example, the script /path/to/script.jsh can access the arguments via the scriptArgs system property. For example:

println(System.getProperty("scriptArgs"))// Prints: script-arg-1 script-arg-2

Staying in Interactive Mode

By default, the OPG4J shell exits after it finishes execution. To stay in interactive mode after the script finishes successfully, pass the --keep_running flag to the shell. For example:

./bin/opg4j -b https://myserver.com:7007/ /path/to/script.jsh --keep_running