README

PHP library for correlation ids management.

Table of contents

• Installation
• Principles
• Usage
• Tests

Installation

$ composer require oat-sa/lib-correlation-ids

Principles

This library provides an interface that will allow access to 3 kind of correlation ids:

• getCurrentCorrelationId(): for the current application process.
• getParentCorrelationId(): for the parent application that calls your application, if any.
• getRootCorrelationId(): for the root application from which all the calls originate in the first place.

Example:

 Request
    |
    v
+---------------+  current: xxx
| Application A |  parent: NULL
+---+-----------+  root: NULL
    |
    v
+---------------+  current: yyy
| Application B |  parent: xxx
+---+-----------+  root: xxx
    |
    v
+---------------+  current: zzz
| Application C |  parent: yyy
+---------------+  root: xxx

Usage

From HTTP context

<?php declare(strict_types=1);

use Psr\Http\Message\RequestInterface;
use OAT\Library\CorrelationIds\Builder\CorrelationIdsRegistryBuilder;
use OAT\Library\CorrelationIds\Generator\CorrelationIdGenerator;

$builder = new CorrelationIdsRegistryBuilder(new CorrelationIdGenerator());

/** @var RequestInterface $request */
$registry = $builder->buildFromRequestHeaders($request->getHeaders());

...

$registry->getCurrentCorrelationId(); // current correlation id
$registry->getParentCorrelationId();  // parent correlation id (nullable)
$registry->getRootCorrelationId();    // root correlation id (nullable)

Note: you can customize the used HTTP headers names by providing you own CorrelationIdsHeaderNamesProviderInterface implementation and pass it to the CorrelationIdsRegistryBuilder constructor.

Manually

<?php declare(strict_types=1);

use OAT\Library\CorrelationIds\Builder\CorrelationIdsRegistryBuilder;
use OAT\Library\CorrelationIds\Generator\CorrelationIdGenerator;

$builder = new CorrelationIdsRegistryBuilder(new CorrelationIdGenerator());

$registry = $builder->build(
    'parentCorrelationId', // optional
    'rootCorrelationId'    // optional
);

Tests

To run tests:

$ vendor/bin/phpunit

Note: see phpunit.xml.dist for available test suites.