Introduction

• Node.js® is an open source, cross-platform JavaScript run-time environment and is a frequently used scripting language available for Linux, MacOS, Windows, and other platforms.
• This article explains how to include Node.js® scripts with JS7 job scripts.
• As a prerequisite to executing Node.js® code it is required to install Node.js on the server for which the JS7 Agent is operated.

Invoking Node.js® from Jobs

Unix

• Find the below examples for download (.json upload): run-Node.js-unix.workflow.json

• In order to directly run Node.js® script code from a JS7 shell job script, the recommended approach is to use a shebang that runs Node.js® as the interpreter of the script like this:
  
  

  Example how run Node.js® script code with a shebang

  #!/usr/bin/node
  
  var name =(process.env.name);
  var num = parseInt(process.env.num);
  
  //print value of variable   
  console.log( name);
  console.log( num);

• Alternatively, the Node.js® script can be executed from a file that has to be located within reach of the JS7 Agent that runs the job:
  
  

  Example how to run Node.js® script code from a file

  node  /some/location/JS7-2.5.1/demo_Node.js

Windows

• Find the below examples for download (.json upload): run-Node.js-windows.workflow.json

• In order to directly run Node.js® script code from a JS7 shell job script, the recommended approach is to use a shebang that runs Node.js® as the interpreter of the script like this:
  
  

  Example how run PowerShell® script code with a shebang replacement

  @@findstr/v "^@@f.*&" "%~f0"|node.exe -&goto:eof
  
  var name =(process.env.name);
  var num = parseInt(process.env.num);
  
  //print value of variable   
  console.log( name);
  console.log( num);

  
  Explanation:

  • • If you consider this shebang replacement somewhat cryptic then add it to JS7 - Script Includes which are easily referenced from shell jobs, e.g. by using ##!include Node
    • The node.exe executable as available from the Node.js® installation is executed by the shebang.
      
      

• In addition, a Node.js® script can be executed from a file that has to be located with the Agent that runs the job:
  
  

  Example how to run Node.js® script code from a file

  node.exe C:\Users\Documents\demo_Node.js

Passing Variables to subsequent Jobs 

Users frequently find a situation when a job creates a result which should be forwarded to subsequent jobs in a workflow.

Download

Download Example for Unix (.json upload): pdwVariablesPassingUnix.workflow.json

Download Example for Windows (.json upload): pdwVariablesPassingWindows.workflow.json

First Job: Write Return Variables

Shell jobs can pass results to subsequent jobs:

• by creating a key/value pair with the syntax: key=value.
• The key/value pair is appended to a temporary file which is provided by JS7 and that is indicated by the JS7_RETURN_VALUES environment variable.
• The key provided is the name of the variable which can be used by subsequent jobs.
  
  • If the variable does not yet exist it will be created on-the-fly.
  • If the variable exists then the value will be overwritten.

The job script implementation looks like this:

#!/usr/bin/node
 
const fs = require('fs');
 
//fetch the env. variables
var name = (process.env.name);
var num = parseInt(process.env.num);
 
//print value of variable   
console.log(name);
console.log( num);

//Modify the values
var num1 = num + num;
console.log( num1);

var name1 = name + " This is JS7 ";
console.log( name1);

//pass results from a key/value pair that is appended to a temporary file provided by JS7

fs.appendFile(process.env.JS7_RETURN_VALUES ,'num1='+num1+'\n',(err) => {});
fs.appendFile(process.env.JS7_RETURN_VALUES ,'name1='+name1+'\n',(err) => {});

@@findstr/v "^@@f.*&" "%~f0"|node.exe -&goto:eof

const fs = require('fs');
 
//fetch the env. variables
var name = (process.env.name);
var num = parseInt(process.env.num);
 
//print value of variable   
console.log(name);
console.log( num);

//Modify the values
var num1 = num + num;
console.log( num1);

var name1 = name + " This is JS7 ";
console.log( name1);

//pass results from a key/value pair that is appended to a temporary file provided by JS7

fs.appendFile(process.env.JS7_RETURN_VALUES ,'num1='+num1+'\n',(err) => {});
fs.appendFile(process.env.JS7_RETURN_VALUES ,'name1='+name1+'\n',(err) => {});

Second Job: Read Variables

Shell jobs access order variables from a mapping to environment variables.

• The JOC Cockpit GUI allows the mapping to be added per job from the right lower corner with the Environment Variables sub-tab.
• The mapping includes free choice of the name of an environment variable which is used in the job script and to assign an existing order variable.
• The spelling of variable names is case-sensitive.

The job script implementation looks like this:

#!/usr/bin/node

var name1 =(process.env.name1);
var num1 = parseInt(process.env.num1);

//print value of variable   
console.log(name1);
console.log( num1);

@@findstr/v "^@@f.*&" "%~f0"|node.exe -&goto:eof

var name1 =(process.env.name1);
var num1 = parseInt(process.env.num1);

//print value of variable   
console.log(name1);
console.log( num1);