How to Log object?

Question

I can see that Log facade is very useful. In the docs of laravel:

The logger provides the eight logging levels defined in RFC 5424: emergency, alert, cr

Answer 1

I've recently started using Laravel, so this certainly works in 5.3 and 5.4, not sure for earlier versions.

The quickest way I can think of (suits smaller objects) would be to cast object to array:

Log::debug((array) $object);

Yo may wonder how's this possible, first param of debug method (as well as error, notice and other logging methods in Log class) accepts string as first param, and we are passing the array.

So, the answer lays down deep in the log writer class. There is a method that gets called every time to support formatting the messages, and it looks like this:

/**
 * Format the parameters for the logger.
 *
 * @param  mixed  $message
 * @return mixed
 */
protected function formatMessage($message)
{
    if (is_array($message)) {
        return var_export($message, true);
    } elseif ($message instanceof Jsonable) {
        return $message->toJson();
    } elseif ($message instanceof Arrayable) {
        return var_export($message->toArray(), true);
    }

    return $message;
}

Also to clarify things little bit more, you can take a look into: https://github.com/laravel/framework/blob/5.4/src/Illuminate/Log/Writer.php#L199 and you'll see that formateMessage method is formatting the message every time.

Answer 2

This will work, although logging the entire model will grow your log rather quickly.

Log::info(print_r($user, true));

The true in the second parameter of the print_r() method returns the information instead of printing it, which allows the Log facade to print it like a string.

Answer 3

You can log either by print_r or json_encode. json_encode is more readable.

For example:

use Illuminate\Support\Facades\Log;

Log::info(json_encode($user)); 

Answer 4

No.

The first parameter must be a string (or a string object representation). If you wish to pass any other type of (raw) data or objects, you can always JSON encode them, and push them in the context settings, like so:

<?php 

$user = User::find($user_id);

\Log::error("Something happened to User {$user_id}.", ['object' => $user->toJson()]);

Or:

<?php

// User.php
[...]

class User 
{
    [...]

    public function __toString()
    {
        return "{$this->id}";
    }
}

// [...]
$user = User::find($user_id);

\Log::error("Something happened to User {$user}.", ['object' => $user->toJson()]);

You can find more information about the method signatures here.

Answer 5

This causes "allocated memory size exhausted" exception in some cases. (e.g native exception class) – Gokigooooks

Had same problem.

Log::info(print_r($request->user()->with('groups'), true ) );

Add ->get()

Log::info(print_r($request->user()->with('groups')->get(), true ) );