JSH – MACHBASE

JSH

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BETA Notice
JSH is currently in beta. Its API and commands are subject to change in future releases.

Since v8.0.52

JSH allows developers to create applications using JavaScript that execute directly within the machbase-neo process. Files with the .js extension are recognized by machbase-neo as executable scripts.

Hello World?

Copy the below code and save as hello.js.

p = require("@jsh/process");
p.print("Hello", "World?", "\n")

Select “JSH” from the “New…” page.

It serves as a straightforward command-line interpreter for executing .js files.

To run the saved script, use the following command:

jsh / > ./hello.js
Hello World?

Commands

exit ends the current JSH session.
ls list files of the current working directory.
cd change workding directory.
ps list all processes and its pid.
kill <pid> terminates the specified process.
servicectl service control, see details

While its functionality is basic, it is sufficient for testing your scripts.

Daemon

For creating applications that run in the background, consider implementing them as daemon processes.

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p = require("@jsh/process")

if( p.ppid() != 1) {
    p.daemonize()
    console.log("svc daemonized")
} else {
    doService()
}

function doService() {
    console.log("svc start - "+p.pid())
    p.addCleanup(()=>{
        // this code be executed when the process is terminated
        console.log("svc stop - "+p.pid())
    })

    sum = 0
    for( i = 0; i < 60; i++) {
        p.sleep(1000)
        sum += i
        console.log("svc pid =", p.pid(), "i =", i)
    }
    console.log("svc sum =", sum)
}

Line 4: daemonize() makes the current application to run as backgound process.
Line 18-22 : it runs every 1 second for a minute.

Save the above code and run, the output messages are printed on the stdout which is the default log writer.

2025/04/28 15:44:25.295 INFO  /sbin/svc.js     svc start - 1035
2025/04/28 15:44:26.296 INFO  /sbin/svc.js     svc pid = 1035 i = 0
2025/04/28 15:44:27.296 INFO  /sbin/svc.js     svc pid = 1035 i = 1
2025/04/28 15:44:28.298 INFO  /sbin/svc.js     svc pid = 1035 i = 2
                ... omit ...
2025/04/28 15:45:24.358 INFO  /sbin/svc.js     svc pid = 1035 i = 58
2025/04/28 15:45:25.360 INFO  /sbin/svc.js     svc pid = 1035 i = 59
2025/04/28 15:45:25.360 INFO  /sbin/svc.js     svc sum = 1770
2025/04/28 15:45:25.360 INFO  /sbin/svc.js     svc stop - 1035

Services

To start background process automatically when machbase-neo starts, Create a JSON file that directs how to start your application.

Create a directory /etc/services and create a JSON file in the directory.

/etc/services/svc.json

{
    "enable": true,
    "start_cmd": "/sbin/svc.js",
    "start_args": []
}

When machbase-neo starts, it scans the /etc/services directory for JSON files. Each JSON file is treated as a service instruction to launch the specified application.

Service Control Commands

servicectl status Display status of services.

servicectl start <service> Start the service of the given name.

servicectl stop <service> Stop the service of the given name.

servicectl reread Re-read the configurations from /etc/services/*.json and shows the changes.

servicectl update Re-read configurations and apply the changes.

Modules

JSH includes various JavaScript modules that can be used in SCRIPT() within TQL and in *.js applications. The exception is the @jsh/process module, which is only available in *.js applications and cannot be used in TQL. Conversely, the TQL context object $, which provides useful methods such as $.yield(), is exclusive to TQL and is not accessible from *.js applications.

For detailed information, refer to the documentation for each module.

Last updated on Apr 30, 2025