Instrument a PHP App

In this guide, we will walk you through the process of setting up and using OpenTelemetry in PHP. You will learn how to instrument a simple PHP application to produce traces, metrics, and logs and export them to KloudMate.

Step 1: Prerequisites

OpenTelemetry requires PHP 8.0+ for automatic instrumentation. Before moving forward ensure that you have the following installed:

• PHP 8.0+
• PECL
• composer

Step 2: Install PHP and setup the app

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1. Create a dice-rolling application

mkdir <project-name> && cd <project-name>

composer init \
 --no-interaction \
 --stability beta \
 --require slim/slim:"^4" \
 --require slim/psr7:"^1"
composer update

2. Write the application code. Create an index.php file in the <project-name> folder and add the following code. The following sample code simulates a dice rolling game that rolls a dice and returns a random number in the range of one to six:

<?php
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Slim\Factory\AppFactory;

require __DIR__ . '/vendor/autoload.php';

$app = AppFactory::create();

$app->get('/rolldice', function (Request $request, Response $response) {
 $result = random_int(1,6);
 $response->getBody()->write(strval($result));
 return $response;
});

$app->run();

Step 3: setup the Opentelemetry auto instrument

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1. Download the tools that are required to build the OpenTelemetry PHP extension.

sudo apt-get install gcc make autoconf
sudo apt update
sudo apt install php-pear php-dev zlib1g-dev libgrpc-dev

2. Use PECL to build the OpenTelemetry PHP extension.

pecl install opentelemetry

The result of the above command

Build process completed successfully
Installing '/usr/lib/php/20230831/opentelemetry.so'
install ok: channel://pecl.php.net/opentelemetry-1.1.0
configuration option "php_ini" is not set to php.ini location
You should add "extension=opentelemetry.so" to php.ini

3. Enable the OpenTelemetry PHP extension. If the Extension opentelemetry enabled in php.ini message is returned in the previous step, skip this step.

Add the following code to the /etc/php/<version>/cli/php.ini file:

[opentelemetry]
extension=opentelemetry.so

4. Verify whether the OpenTelemetry PHP extension is built and enabled.

Method 1:

php -m | grep opentelemetry

Expected output:

opentelemetry

5. Add additional dependencies required for OpenTelemetry SDK for PHP to perform automatic instrumentation on the dice-rolling application.

pecl install grpc

The above command will run for an extended period of time.

After successful completion run the below command

composer config allow-plugins.php-http/discovery false
composer require \
  open-telemetry/sdk \
  open-telemetry/exporter-otlp \
  php-http/guzzle7-adapter \
  open-telemetry/opentelemetry-auto-slim

6. Set environment variables and run the app

env OTEL_PHP_AUTOLOAD_ENABLED=true \
 OTEL_SERVICE_NAME=myapp \
 OTEL_TRACES_EXPORTER=otlp \
 OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf \
 OTEL_EXPORTER_OTLP_ENDPOINT=https://otel.kloudmate.com:4318 \
 OTEL_EXPORTER_OTLP_HEADERS="Authorization=<token>" \
 OTEL_PROPAGATORS=baggage,tracecontext \
 php -S localhost:8080

Replace <token>with your API key

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Source URL for the example application: Getting Started with OpenTelemetry PHP