### Initialize Jaeger Tracer and Start/End Span

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Demonstrates how to initialize the Jaeger tracer with a configuration, start an active span, perform operations, close the span, and flush the tracer. This is a basic example of instrumenting a PHP application.

```php
<?php

require_once 'vendor/autoload.php';

use Jaeger\Config;
use OpenTracing\GlobalTracer;

$config = new Config(
    [
        'sampler' => [
            'type' => Jaeger\SAMPLER_TYPE_CONST,
            'param' => true,
        ],
        'logging' => true,
    ],
    'your-app-name'
);
$config->initializeTracer();

$tracer = GlobalTracer::get();

$scope = $tracer->startActiveSpan('TestSpan', []);
$scope->close();

$tracer->flush();

```

--------------------------------

### Install Dependencies with Composer

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/tests/README.md

Installs project dependencies, including PHPUnit, using Composer. This command should be run from the project's root directory.

```Bash
# run this command from project root
$ composer install
```

--------------------------------

### Install Jaeger Client PHP

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Installs the Jaeger client library for PHP using Composer. This is the primary method for integrating the library into your project.

```bash
composer require jonahgeorge/jaeger-client-php
```

--------------------------------

### Jaeger Dispatch Mode Configuration

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Illustrates how to configure the dispatch mode for sending trace data to Jaeger. It shows the available constants and an example configuration array.

```php
class Config
{
    const ZIPKIN_OVER_COMPACT_UDP   = "zipkin_over_compact_udp";
    const JAEGER_OVER_BINARY_UDP    = "jaeger_over_binary_udp";
    const JAEGER_OVER_BINARY_HTTP   = "jaeger_over_binary_http";
    ...
}
```

```php
// config.php

use Jaeger\Config;

return [
    'sampler' => [
        'type' => Jaeger\SAMPLER_TYPE_CONST,
        'param' => true,
    ],
    'logging' => true,
    "tags" => [
        // process. prefix works only with JAEGER_OVER_HTTP, JAEGER_OVER_BINARY
        // otherwise it will be shown as simple global tag
        "process.process-tag-key-1" => "process-value-1", // all tags with `process.` prefix goes to process section
        "process.process-tag-key-2" => "process-value-2", // all tags with `process.` prefix goes to process section
        "global-tag-key-1" => "global-tag-value-1", // this tag will be appended to all spans
        "global-tag-key-2" => "global-tag-value-2", // this tag will be appended to all spans
    ],
    "local_agent" => [
        "reporting_host" => "localhost", 
//        You can override port by setting local_agent.reporting_port value   
        "reporting_port" => 6832
    ],
//     Different ways to send data to Jaeger. Config::ZIPKIN_OVER_COMPACT - default):
    'dispatch_mode' => Config::JAEGER_OVER_BINARY_UDP,
];

```

--------------------------------

### Configure Jaeger Client for IPv6 (PHP)

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Demonstrates how to configure the Jaeger client for PHP to use IPv6 by setting the 'ip_version' configuration option. This example shows the direct use of the 'ip_version' key.

```php
use Jaeger\Config;

$config = new Config(
    [
        "ip_version" => Config::IPV6, // <-- or use Config::IP_VERSION constant
        'logging' => true,
        'dispatch_mode' => Config::JAEGER_OVER_BINARY_UDP,
    ],
    'serviceNameExample',
);
$config->initializeTracer();
```

--------------------------------

### Jaeger Sampler Configurations

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Provides configurations for different Jaeger samplers: Const, Probabilistic, and Rate Limiting. Each sampler has specific parameters for controlling trace sampling behavior.

```php
'sampler' => [
    'type' => Jaeger\SAMPLER_TYPE_CONST,
    'param' => true, // boolean wheter to trace or not
]
```

```php
'sampler' => [
    'type' => Jaeger\SAMPLER_TYPE_PROBABILISTIC,
    'param' => 0.5, // float [0.0, 1.0]
]
```

```php
'sampler' => [
    'type' => Jaeger\SAMPLER_TYPE_RATE_LIMITING,
    'param' => 100, // integer maximum number of traces per second,
    'cache' => [
        'currentBalanceKey' => 'rate.currentBalance' // string
        'lastTickKey' => 'rate.lastTick' // string
    ]
]
```

--------------------------------

### Run Tests with Docker for PHP 7.1

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/tests/README.md

Executes the PHP unit tests using a Docker container with PHP 7.1. This command mounts the current directory into the container and runs the test script.

```Bash
$ docker run --rm -it -v $(pwd):/usr/app php:7.1 ./usr/app/tests/php-test.sh
```

--------------------------------

### Run Unit Tests

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/tests/README.md

Executes all defined unit tests for the Jaeger PHP client library using Composer's test script.

```Bash
$ composer test
```

--------------------------------

### Run Tests with Docker for PHP 7.0

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/tests/README.md

Executes the PHP unit tests using a Docker container with PHP 7.0. This command mounts the current directory into the container and runs the test script.

```Bash
$ docker run --rm -it -v $(pwd):/usr/app php:7.0 ./usr/app/tests/php-test.sh
```

--------------------------------

### Run Tests with Docker for PHP 7.2

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/tests/README.md

Executes the PHP unit tests using a Docker container with PHP 7.2. This command mounts the current directory into the container and runs the test script.

```Bash
$ docker run --rm -it -v $(pwd):/usr/app php:7.2 ./usr/app/tests/php-test.sh
```

--------------------------------

### Configure Jaeger Client for IPv6 using Constant (PHP)

Source: https://github.com/jonahgeorge/jaeger-client-php/blob/master/README.md

Demonstrates an alternative way to configure the Jaeger client for PHP to use IPv6, utilizing the Config::IP_VERSION constant for the configuration key. This provides a more readable and maintainable configuration.

```php
use Jaeger\Config;

$config = new Config(
    [
        Config::IP_VERSION => Config::IPV6, // <-
        'logging' => true,
        'dispatch_mode' => Config::JAEGER_OVER_BINARY_UDP,
    ],
    'serviceNameExample',
);
$config->initializeTracer();
```

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