README

Automatic OpenTelemetry tracing for PHP methods via the #[Traceable] attribute. Framework-agnostic core — mark any class with the attribute, and spans are created automatically using the ext-opentelemetry hook API.

This is a read-only sub-split. Please open issues and pull requests in the monorepo.

Installation

composer require eerzho/opentelemetry-auto-class

Requirements:

ext-opentelemetry
PHP 8.2+

Usage

Basic

Add #[Traceable] to a class — all public methods will be traced automatically:

use OpenTelemetry\Contrib\Instrumentation\Class\Attribute\Traceable;
use OpenTelemetry\Contrib\Instrumentation\Class\AttributeScanner;
use OpenTelemetry\Contrib\Instrumentation\Class\ClassInstrumentation;

#[Traceable]
class OrderService
{
    public function create(array $items): void
    {
        // span "OrderService::create" is created automatically
    }

    public function cancel(int $orderId): void
    {
        // span "OrderService::cancel" is created automatically
    }
}

// Register instrumentation
$map = AttributeScanner::scan([OrderService::class]);
ClassInstrumentation::register($map);

For Laravel and Symfony, use the framework integrations that handle class discovery automatically: opentelemetry-auto-class-laravel / opentelemetry-auto-class-symfony

Exclude methods

Use the exclude parameter to skip specific methods from tracing:

use OpenTelemetry\Contrib\Instrumentation\Class\Attribute\Traceable;

#[Traceable(exclude: ['healthCheck', 'getVersion'])]
class PaymentService
{
    public function charge(int $amount, string $currency): void
    {
        // traced
    }

    public function healthCheck(): bool
    {
        // NOT traced
        return true;
    }

    public function getVersion(): string
    {
        // NOT traced
        return '1.0.0';
    }
}

Exclude arguments

By default, all method arguments are captured as span attributes. Use #[Arguments(exclude: [...])] on a method to hide sensitive parameters:

use OpenTelemetry\Contrib\Instrumentation\Class\Attribute\Arguments;
use OpenTelemetry\Contrib\Instrumentation\Class\Attribute\Traceable;

#[Traceable]
class AuthService
{
    #[Arguments(exclude: ['password', 'token'])]
    public function login(string $email, string $password, string $token): void
    {
        // span captures "email" attribute only
        // "password" and "token" are excluded
    }

    public function logout(int $userId): void
    {
        // span captures "userId" attribute (no exclusions)
    }
}

Without attributes

You can register classes for tracing without using #[Traceable] — build the method map manually and pass it to ClassInstrumentation::register():

class OrderService
{
    public function create(array $items, int $priority, string $note): void {}

    public function cancel(int $orderId): void {}

    public function archive(int $orderId): void {}
}

use OpenTelemetry\Contrib\Instrumentation\Class\ClassInstrumentation;

ClassInstrumentation::register([
    OrderService::class => [
        // trace with arguments, skip 'priority' (position 1)
        'create' => ['items' => 0, 'note' => 2],
        // trace without capturing arguments
        'cancel' => [],
        // 'archive' is not listed — it will NOT be traced
    ],
]);

Each entry maps a class to its methods, and each method to its arguments (parameter name => position). Methods not listed are not traced. Arguments not listed are not captured.

How it works

Each traced method call produces a span:

Name: ClassName::methodName
Kind: INTERNAL

With attributes:

Attribute	Value
`code.function.name`	`ClassName::methodName`
`code.file.path`	File where the method is defined
`code.line.number`	Line number of the method
Method arguments	Parameter name → serialized value

If a method throws an exception, the span records an exception event and sets status to ERROR:

Event attribute	Value
`exception.type`	Exception class name
`exception.message`	Exception message
`exception.stacktrace`	Full stack trace

Argument serialization

Arguments are serialized to span-compatible types:

Type	Result	Example
`string`, `int`, `float`, `bool`	As-is	`"hello"`, `42`, `3.14`, `true`
`null`	`"null"`	`null` → `"null"`
`BackedEnum`	Backing value	`Status::Active` → `"active"`
Object with `__toString()`	String cast	`$money` → `"100 USD"`
Object without `__toString()`	Class name (FQCN)	`$dto` → `"App\DTO\Order"`
`array`	JSON string	`[1, 2]` → `"[1,2]"`
Other (`resource`, ...)	`gettype()` result	`"resource"`

If JSON encoding of an array fails, the value is serialized as "array".

Disabling instrumentation

To disable tracing at runtime, use the standard OpenTelemetry environment variable:

OTEL_PHP_DISABLED_INSTRUMENTATIONS=class

Limitations

Only public methods are traced (protected and private are ignored)
Abstract classes, interfaces, traits, and enums are skipped
Requires ext-opentelemetry installed and loaded

License

MIT

eerzho / opentelemetry-auto-class

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