improve psr3 log context formatting

string values may contain data that causes export to choke, so:
- json encode/decode strings and arrays that may contain strings, using JSON_INVALID_UTF8_SUBSTITUTE
- only allow objects that are stringable or json serializable
- allow other primitive types

Author: brettmc

src/Instrumentation/Psr3/composer.json

@@ -36,6 +36,7 @@
     "cakephp/log": "*",
     "monolog/monolog": "*",
     "symfony/console": "*",
+    "symfony/uid": "*",
     "yiisoft/log": "*",
     "friendsofphp/php-cs-fixer": "^3",
     "phan/phan": "^5.0",

src/Instrumentation/Psr3/src/Formatter.php

@@ -4,18 +4,52 @@
 
 namespace OpenTelemetry\Contrib\Instrumentation\Psr3;
 
+use JsonSerializable;
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use Stringable;
 use Throwable;
 
 class Formatter
 {
+
+    use LogsMessagesTrait;
+
     public static function format(array $context): array
     {
         $formatted = [];
         foreach ($context as $key => $value) {
             if ($key === 'exception' && $value instanceof Throwable) {
                 $formatted[$key] = self::formatThrowable($value);
             } else {
-                $formatted[$key] = json_decode(json_encode($value) ?: '');
+                switch (gettype($value)) {
+                    case 'integer':
+                    case 'double':
+                    case 'boolean':
+                        $formatted[$key] = $value;
+
+                        break;
+                    case 'string':
+                    case 'array':
+                        // Handle UTF-8 encoding issues
+                        $encoded = json_encode($value, JSON_INVALID_UTF8_SUBSTITUTE);
+                        if ($encoded === false) {
+                            self::logWarning('Failed to encode value: ' . json_last_error_msg());
+                        } else {
+                            $formatted[$key] = json_decode($encoded);
+                        }
+
+                        break;
+                    case 'object':
+                        if ($value instanceof Stringable) {
+                            $formatted[$key] = (string) $value;
+                        } elseif ($value instanceof JsonSerializable) {
+                            $formatted[$key] = $value->jsonSerialize();
+                        }
+
+                        break;
+                    default:
+                        //do nothing
+                }
             }
         }
 

src/Instrumentation/Psr3/tests/phpt/export_context.phpt

@@ -0,0 +1,110 @@
+--TEST--
+Test generating otel LogRecord with complex message context
+--FILE--
+
+<?php
+use OpenTelemetry\API\Globals;
+use Psr\Log\LoggerInterface;
+use Psr\Log\LoggerTrait;
+
+putenv('OTEL_PHP_AUTOLOAD_ENABLED=true');
+putenv('OTEL_LOGS_EXPORTER=console');
+putenv('OTEL_TRACES_EXPORTER=none');
+putenv('OTEL_METRICS_EXPORTER=none');
+putenv('OTEL_PHP_DETECTORS=none');
+putenv('OTEL_PHP_PSR3_MODE=export');
+
+require dirname(__DIR__, 2) . '/vendor/autoload.php';
+
+$logger = new class implements LoggerInterface{
+    use LoggerTrait;
+    public function log($level, string|\Stringable $message, array $context = []): void {}
+};
+
+$span = Globals::tracerProvider()->getTracer('demo')->spanBuilder('root')->startSpan();
+$scope = $span->activate();
+
+$context = [
+    's' => 'string',
+    'i' => 1234,
+    'l' => 3.14159,
+    't' => true,
+    'f' => false,
+    'stringable' => new class() implements \Stringable {
+        public function __toString(): string
+        {
+            return 'some_string';
+        }
+    },
+    'j' => new class() implements JsonSerializable {
+        public function jsonSerialize(): array
+        {
+            return ['key' => 'value'];
+        }
+    },
+    'array' => ['a', 'b', 'c'],
+    'exception' => new \Exception('my_exception'),
+    'bin' => \Symfony\Component\Uid\Uuid::v4()->toBinary(),
+];
+
+
+$logger->info('test message', $context);
+
+$scope->detach();
+$span->end();
+?>
+
+--EXPECTF--
+{
+    "resource": {
+        "attributes": [],
+        "dropped_attributes_count": 0
+    },
+    "scopes": [
+        {
+            "name": "io.opentelemetry.contrib.php.psr3",
+            "version": null,
+            "attributes": [],
+            "dropped_attributes_count": 0,
+            "schema_url": "https:\/\/opentelemetry.io\/schemas\/%s",
+            "logs": [
+                {
+                    "timestamp": null,
+                    "observed_timestamp": %d,
+                    "severity_number": %d,
+                    "severity_text": null,
+                    "body": "test message",
+                    "trace_id": "%s",
+                    "span_id": "%s",
+                    "trace_flags": 1,
+                    "attributes": {
+                        "s": "string",
+                        "i": 1234,
+                        "l": 3.14159,
+                        "t": true,
+                        "f": false,
+                        "stringable": "some_string",
+                        "j": {
+                            "key": "value"
+                        },
+                        "array": [
+                            "a",
+                            "b",
+                            "c"
+                        ],
+                        "exception": {
+                            "message": "my_exception",
+                            "code": 0,
+                            "file": "Standard input code",
+                            "line": %d,
+                            "trace": [],
+                            "previous": []
+                        },
+                        "bin": "%s"
+                    },
+                    "dropped_attributes_count": 0
+                }
+            ]
+        }
+    ]
+}