Log

Once properly set up, you can add and leave logging throughout the application code end environmental configuration will pipe the output when and where appropiate.

Table of Contents

• Class specification
• Usage
• Handlers

Usage

You can use the Log::log method and pass in the level or use the level as a convenient shorthand, like so:

Log::debug("Only strings can be logged");

See levels below for the different valid debug levels.

Handlers

You may use multiple handlers, and each of them will recieve the log message and context you provide and decide on their own what, if anything to do with it. If that is put the log at the end of a file or in a db or something else.

Handers are callables that follow the following interface: function(string $level, string $message, array $context = []): void

Standard out/error handler

When developing locally, the most convenient log handler is just to output to stdout and stderr so the logs will be put the same place that native errors and warnings are put by the local php -s server. You can do this very easily by adding something like this to your configuration (after the current environment is defined):

if (Environment::current() == Environment::LOCAL) {
    Log::handler('standard', [Log::class, 'std']);
}

This is because a default “php standard out” handler is provided in the Log class for your convenience. You can easily replace it with your own. Here is the default one to show you how you can do that:

function std(string $level, string $message, array $context = []): void
{
    $level = strtoupper($level);
    $string = "{$level}: {$message}\n";
    if (in_array($level, ['INFO', 'DEBUG', 'NOTICE'])) {
        $channel = 'php://stdout';
    } else {
        $channel = 'php://stderr';
    }
    file_put_contents($channel, $string);
}

File handler

Should you want a quick log file handler for initial testing, one is also provided, but this should be replaced by a more robus one for any production setup.

To set it up, you must configure a path that is writeable by PHP. The logs_path config string is expected for this purpose. Example: Environment::put('logs_path', '/some/where/writeable');

Any attempts to log with this handler enabled and the config is missing or the folder/file is not writable, will throw ConfigMissing exception.

The file will be called app.log and the logged messages will be prefixed with YYYY-MM-DD HH:ii:ss LEVEL , and suffixed with \n:

Log::info("This is a test");
// -> 2019-12-24 15:45:12 INFO This is a test

This handler opens the file and appends on each call. A solution you could make for a more permanent solution would be to remember the file handle until a destructor.

Levels

Follows PSR-3. See github.com/php-fig/log.

These are the log levels and their expected order:

1. Emergency: system is unusable
2. Alert: action must be taken immediately
3. Critical: critical conditions
4. Error: error conditions
5. Warning: warning conditions
6. Notice: normal but significant condition
7. Informational: informational messages
8. Debug: debug-level messages

Class specification

/**
 * Send $message with level $level to all handlers
 *
 * @param string $level
 * @param string $message
 * @param array $context
 */
public static function log($level, $message, array $context = []): void;

/**
 * Send $message of the level specified by method name to all handlers
 *
 * @param string $message
 * @param array $context
 */
public static function debug(string $message, array $context = []): void;
public static function info(string $message, array $context = []): void;
public static function notice(string $message, array $context = []): void;
public static function warning(string $message, array $context = []): void;
public static function error(string $message, array $context = []): void;
public static function critical(string $message, array $context = []): void;
public static function alert(string $message, array $context = []): void;
public static function emergency(string $message, array $context = []): void;


/**
 * Add handler, it should implement Psr\Log\LoggerInterface
 *
 * @param string $name unique name for this handler
 * @param object|callable $handler an object that implement Psr\Log\LoggerInterface or a callable
 */
public static function handler(string $name, $handler): void