finish off psr-18 auto-instrumentation (#88)

- add tests
- replace enum with class for php8.0 compatibility
- set up auto-registration via composer autoloader
- mention sdk autoloading in readme
- document some todos/questions

.github/workflows/php.yml

@@ -21,13 +21,16 @@ jobs:
           'Context/Swoole',
           'Instrumentation/Slim',
           'Instrumentation/Psr15',
+          'Instrumentation/Psr18',
           'Symfony'
         ]
         exclude:
           - project: 'Instrumentation/Slim'
             php-version: 7.4
           - project: 'Instrumentation/Psr15'
             php-version: 7.4
+          - project: 'Instrumentation/Psr18'
+            php-version: 7.4
 
     steps:
     - uses: actions/checkout@v3

.gitsplit.yml

@@ -12,6 +12,8 @@ splits:
     target: "https://${GH_TOKEN}@github.com/opentelemetry-php/contrib-sdk-bundle.git"
   - prefix: "src/Instrumentation/Psr15"
     target: "https://${GH_TOKEN}@github.com/opentelemetry-php/contrib-auto-psr15.git"
+  - prefix: "src/Instrumentation/Psr18"
+    target: "https://${GH_TOKEN}@github.com/opentelemetry-php/contrib-auto-psr18.git"
   - prefix: "src/Instrumentation/Slim"
     target: "https://${GH_TOKEN}@github.com/opentelemetry-php/contrib-auto-slim.git"
   - prefix: "src/Context/Swoole"

examples/instrumentation/Psr18/request.php

@@ -14,7 +14,6 @@
 use OpenTelemetry\SDK\Trace\TracerProvider;
 
 require_once dirname(__DIR__, 3) . '/vendor/autoload.php';
-require_once dirname(__DIR__, 3) . '/src/Instrumentation/Psr18/client_tracing.php';
 
 $tracerProvider =  new TracerProvider(
     new BatchSpanProcessor(new ConsoleSpanExporter(), ClockFactory::getDefault()),

src/Instrumentation/Psr18/.php-cs-fixer.php

@@ -0,0 +1,43 @@
+<?php
+$finder = PhpCsFixer\Finder::create()
+    ->exclude('vendor')
+    ->exclude('var/cache')
+    ->in(__DIR__);
+
+$config = new PhpCsFixer\Config();
+return $config->setRules([
+    'concat_space' => ['spacing' => 'one'],
+    'declare_equal_normalize' => ['space' => 'none'],
+    'is_null' => true,
+    'modernize_types_casting' => true,
+    'ordered_imports' => true,
+    'php_unit_construct' => true,
+    'single_line_comment_style' => true,
+    'yoda_style' => false,
+    '@PSR2' => true,
+    'array_syntax' => ['syntax' => 'short'],
+    'blank_line_after_opening_tag' => true,
+    'blank_line_before_statement' => true,
+    'cast_spaces' => true,
+    'declare_strict_types' => true,
+    'function_typehint_space' => true,
+    'include' => true,
+    'lowercase_cast' => true,
+    'new_with_braces' => true,
+    'no_extra_blank_lines' => true,
+    'no_leading_import_slash' => true,
+    'echo_tag_syntax' => true,
+    'no_unused_imports' => true,
+    'no_useless_else' => true,
+    'no_useless_return' => true,
+    'phpdoc_order' => true,
+    'phpdoc_scalar' => true,
+    'phpdoc_types' => true,
+    'short_scalar_cast' => true,
+    'single_blank_line_before_namespace' => true,
+    'single_quote' => true,
+    'trailing_comma_in_multiline' => true,
+    ])
+    ->setRiskyAllowed(true)
+    ->setFinder($finder);
+

src/Instrumentation/Psr18/README.md

@@ -0,0 +1,32 @@
+# OpenTelemetry PSR-18 auto-instrumentation
+
+## Requirements
+
+* OpenTelemetry extension
+* OpenTelemetry SDK an exporter (required to actually export traces)
+* A psr-18 client
+* (optional) OpenTelemetry [SDK Autoloading](https://github.com/open-telemetry/opentelemetry-php/blob/main/examples/autoload_sdk.php) configured
+
+## Overview
+Auto-instrumentation hooks are registered via composer, which will:
+
+* create spans automatically for each PSR-18 request that is sent
+* add a `traceparent` header to the request to facilitate distributed tracing.
+
+## Manual configuration
+If you are not using SDK autoloading, you will need to create and register a `TracerProvider` early in your application's lifecycle:
+
+```php
+<?php
+require_once 'vendor/autoload.php';
+
+$tracerProvider = /*create tracer provider*/;
+$scope = \OpenTelemetry\API\Common\Instrumentation\Configurator::create()
+    ->withTracerProvider($tracerProvider)
+    ->activate();
+
+$client->sendRequest($request);
+
+$scope->detach();
+$tracerProvider->shutdown();
+```

src/Instrumentation/Psr18/_register.php

@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+\OpenTelemetry\Contrib\Instrumentation\Psr18\Psr18Instrumentation::register();

src/Instrumentation/Psr18/composer.json

@@ -0,0 +1,36 @@
+{
+  "name": "open-telemetry/opentelemetry-auto-psr18",
+  "description": "OpenTelemetry auto-instrumentation for psr18 http clients.",
+  "keywords": ["opentelemetry", "otel", "open-telemetry", "tracing", "psr18", "instrumentation"],
+  "type": "library",
+  "homepage": "https://opentelemetry.io/docs/php",
+  "readme": "./README.md",
+  "license": "Apache-2.0",
+  "minimum-stability": "dev",
+  "require": {
+    "php": "^8.0",
+    "ext-otel_instrumentation": "*",
+    "open-telemetry/api": "^0",
+    "psr/http-client": "^1"
+  },
+  "autoload": {
+    "psr-4": {
+      "OpenTelemetry\\Contrib\\Instrumentation\\Psr18\\": "src/"
+    },
+    "files": [
+      "_register.php"
+    ]
+  },
+  "require-dev": {
+    "friendsofphp/php-cs-fixer": "^3",
+    "nyholm/psr7": "*",
+    "phan/phan": "^5.0",
+    "php-http/mock-client": "*",
+    "phpstan/phpstan": "^1.1",
+    "phpstan/phpstan-phpunit": "^1.0",
+    "psalm/plugin-phpunit": "^0.16",
+    "open-telemetry/sdk": "^0",
+    "phpunit/phpunit": "^9.5",
+    "vimeo/psalm": "^4.0"
+  }
+}

src/Instrumentation/Psr18/phpstan.neon.dist

@@ -0,0 +1,9 @@
+includes:
+    - vendor/phpstan/phpstan-phpunit/extension.neon
+
+parameters:
+    tmpDir: var/cache/phpstan
+    level: 5
+    paths:
+        - src
+        - tests

src/Instrumentation/Psr18/phpunit.xml.dist

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
+    backupGlobals="false"
+    backupStaticAttributes="false"
+    cacheResult="false"
+    colors="false"
+    convertErrorsToExceptions="true"
+    convertNoticesToExceptions="true"
+    convertWarningsToExceptions="true"
+    forceCoversAnnotation="false"
+    processIsolation="false"
+    stopOnError="false"
+    stopOnFailure="false"
+    stopOnIncomplete="false"
+    stopOnSkipped="false"
+    stopOnRisky="false"
+    timeoutForSmallTests="1"
+    timeoutForMediumTests="10"
+    timeoutForLargeTests="60"
+    verbose="true">
+
+    <coverage processUncoveredFiles="true" disableCodeCoverageIgnore="false">
+        <include>
+            <directory>src</directory>
+        </include>
+    </coverage>
+
+    <php>
+        <ini name="date.timezone" value="UTC" />
+        <ini name="display_errors" value="On" />
+        <ini name="display_startup_errors" value="On" />
+        <ini name="error_reporting" value="E_ALL" />
+    </php>
+
+    <testsuites>
+        <testsuite name="unit">
+            <directory>tests/Unit</directory>
+        </testsuite>
+        <testsuite name="integration">
+            <directory>tests/Integration</directory>
+        </testsuite>
+    </testsuites>
+
+</phpunit>

src/Instrumentation/Psr18/psalm.xml.dist

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="3"
+    cacheDirectory="var/cache/psalm"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd">
+    <projectFiles>
+        <directory name="src"/>
+        <directory name="tests"/>
+    </projectFiles>
+    <plugins>
+        <pluginClass class="Psalm\PhpUnitPlugin\Plugin"/>
+    </plugins>
+</psalm>

src/Instrumentation/Psr18/HeadersPropagator.php → src/Instrumentation/Psr18/src/HeadersPropagator.php

@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry\Instrumentation\Psr18;
+namespace OpenTelemetry\Contrib\Instrumentation\Psr18;
 
 use function assert;
 use OpenTelemetry\Context\Propagation\PropagationSetterInterface;
@@ -11,9 +11,14 @@
 /**
  * @internal
  */
-enum HeadersPropagator implements PropagationSetterInterface
+class HeadersPropagator implements PropagationSetterInterface
 {
-    case Instance;
+    public static function instance(): self
+    {
+        static $instance;
+
+        return $instance ??= new self();
+    }
 
     public function set(&$carrier, string $key, string $value): void
     {