OrientDB server function versioning

What & Why

• All javascript functions exist within OrientDB as OFunction rows or objects

• My current approach is to export schema into a single gz & ODB server-side functions in json file.

• The problem with this approach is ODB function changes are not tracked with git system, see https://github.com/jymcheong/OpenEDR/commit/a2f0ffb8c6d457c6bca8cdb731091c23490e9c9a

What you will learn

• be proficient with git; fork OpenEDR, make changes, Pull-Request...

• nodeJS scripting related to OrientDB data-structures

• be proficient with Visual Studio Code execution breakpoint stepping through

How

Extend existing export.sh

• Line 15 of exportFunctions_ORole.js was written because the official export method was VERY SLOW.

• First thing first, understand the data-structure of OFunction such that we can represent ALL the server side javascript functions appropriately as individual files

YJ's Documentation

Overview of exportFunctions.js

Purpose of exportFunctions.js

Output of exportFunctions.js

• @type

• @version

• @class

• idempotent - Specifies whether the function performs idempotent queries or executes non-idempotent commands

• code - Contains code of the function

• name - Specifies the name of the function

• language - Specifies the scripting language used by the function

• parameters - Specifies the parameters of the function

Codes Explanation

1. Connect to ODB

2. Create a variable called output of value '{"records":['

3. Retrieve ALL data from OFunction and convert it into JSON format. This is then stored into variable results.
• The JavaScript ODB server-side functions are stored in the special OFunction class.
• Structure of OFunction class:



As shown in the red box above, OFunction class has 8 properties.
• Output of the query in Line 14:



From the results of the query, we can see that it is returning all data for every entry in OFunction.

4. For each element in array results, it gets parsed into variable line. I added console.log(line) after line 16 to see the value of variable line. This is a snippet of the output:



From the screenshot above, we can see that it is parsing one function at a time to variable line.
For every function, the script will delete the field @rid as seen in line 17 of exportFunctions.js i.e. delete line["@rid"]. Lastly, it will convert variable line into JSON string and append it to variable output. Each JSON string that gets appended will be separated by a comma.

5. After all JSON strings have been appended, "]}" is appended at the end of variable output.

6. Write variable output to functionsONLY.json

Extend existing exportFunctions.js

To-do list

1. Export into JavaScript file per ODB function instead of JSON files (file name should match the ODB function name)

2. Move parameter fields to the top as comments

3. Replace \n in code field with actual newlines for IDE viewing

Modified exportFunction.js codes

/***
 * This script exports every ODB server-side function into individual JavaScript file    
***/

const fs = require("fs")
const connectODB = require('../../common/orientdb').connectODB;
const fields = ["@version","@class","idempotent","code","name","language","parameters"]

async function exportFunctions(){
    _session = await connectODB()
    var output = '{"records":[';
    let results = await _session.query("select @this.toJSON() from OFunction").all();
    for(var i = 0; i < results.length; i++) {
        var line = JSON.parse(results[i]['@this.toJSON()']);
        delete line["@rid"]
        var output = '//@type\n'
				output += line["@type"]+'\n\n'
				for(var k = 0; k < fields.length; k++) {
					output += '//'+fields[k]+'\n'
					output += line[fields[k]]+'\n\n'
				}
				//console.log(output)
				fs.writeFile(line['name']+'.js', output, function(err) {
					if(err) {
						return console.log(err);
					}
					console.log("The file was saved!");
					process.exit();
				});
    }
}

exportFunctions();

Codes Explanation

Output of modified exportFunctions.js

Jym's Review, Test & Integration

Slight refactoring

As explained to , I still need the original / existing exportFunctions.js that creates output files that are directly consumed during installation by Orientdb container's entrypoint script.

Really satisfying to work with because our ideas can turn into good implementation. It worked nicely as shown above after slight refactoring. Switching to Github Desktop, we see:

Other enhancement(s) to this enhancement

• To delete all odbFunctions/*.js before export because we don't want "orphans" (eg. we decide to rename a function..)

• I re-ordered to `const fields = ["@version","@class","idempotent","parameters","name","language","code"]` because from a readability standpoint, we want to know the parameters we use with this function upfront or earlier, rather at the end.

To-do

• Implement & test the delete-before-export changes

• Update GH master & dev exportScripts & common, still based on old way.

• Merge these changes to GH master & dev (including the new script outputs for tracking)

merged @ https://github.com/jymcheong/OpenEDR/pull/25