Logging

The Market Data PHP SDK supports PSR-3 compatible logging for debugging and monitoring API interactions.

Default Logging

The SDK creates a default logger based on the MARKETDATA_LOGGING_LEVEL environment variable:

<?php

// Set logging level via environment variable
putenv('MARKETDATA_LOGGING_LEVEL=debug');

use MarketDataApp\Client;

$client = new Client();

// Debug messages will be logged to stderr
$quote = $client->stocks->quote('AAPL');

Available Log Levels

The SDK supports standard PSR-3 log levels:

Level	Description
emergency	System is unusable
alert	Action must be taken immediately
critical	Critical conditions
error	Error conditions
warning	Warning conditions
notice	Normal but significant conditions
info	Informational messages
debug	Debug-level messages (most verbose)

Custom Logger

Inject your own PSR-3 compatible logger:

Monolog

<?php

use MarketDataApp\Client;
use Monolog\Logger;
use Monolog\Handler\StreamHandler;
use Monolog\Handler\RotatingFileHandler;

// Create Monolog logger
$logger = new Logger('marketdata');

// Log to file with rotation
$logger->pushHandler(new RotatingFileHandler(
    '/var/log/marketdata/api.log',
    maxFiles: 7,
    level: Logger::DEBUG
));

// Also log errors to stderr
$logger->pushHandler(new StreamHandler(
    'php://stderr',
    level: Logger::ERROR
));

// Pass logger to client
$client = new Client(logger: $logger);

$quote = $client->stocks->quote('AAPL');

Custom PSR-3 Logger

<?php

use MarketDataApp\Client;
use Psr\Log\AbstractLogger;
use Psr\Log\LogLevel;

// Create a simple custom logger
class SimpleLogger extends AbstractLogger
{
    public function log($level, $message, array $context = []): void
    {
        $timestamp = date('Y-m-d H:i:s');
        $contextStr = !empty($context) ? json_encode($context) : '';
        echo "[{$timestamp}] [{$level}] {$message} {$contextStr}\n";
    }
}

$logger = new SimpleLogger();
$client = new Client(logger: $logger);

$quote = $client->stocks->quote('AAPL');

What Gets Logged

The SDK logs the following events:

Debug Level

• API request URLs and parameters
• Response status codes
• Retry attempts

Info Level

• Successful API responses
• Rate limit information

Warning Level

• Retry attempts after transient failures
• Deprecated endpoint usage

Error Level

• API errors and exceptions
• Authentication failures
• Network errors

Example Log Output

[2024-01-15 10:30:00] [debug] Making request: GET https://api.marketdata.app/v1/stocks/quotes/?symbol=AAPL
[2024-01-15 10:30:01] [debug] Response received: 200 OK
[2024-01-15 10:30:01] [info] Rate limits - Used: 1, Remaining: 9999, Limit: 10000

Disabling Logging

To disable logging, set the log level to a high threshold or provide a null logger:

<?php

use MarketDataApp\Client;
use Psr\Log\NullLogger;

// Option 1: Use NullLogger
$client = new Client(logger: new NullLogger());

// Option 2: Set high log level via environment
putenv('MARKETDATA_LOGGING_LEVEL=emergency');
$client = new Client();

Production Recommendations

• Use warning or error level in production to reduce log volume
• Use debug level only during development or troubleshooting
• Configure log rotation to prevent disk space issues
• Consider using structured logging (JSON format) for log aggregation systems