How to write logs from one service into separate file?

Question

Normally you just get logger service, and logs go to:

%kernel.root_dir%/%kernel.environment%.log

I would like to log messages

Answer 1

I solved the same issue by creating custom channels in config.yml as explained in this link How to Log Messages to different Files.

monolog:
    channels: ['my_logger']

    handlers:
        my_logger:
            level:    debug
            type:     stream
            path:     '%kernel.logs_dir%/my_logger.log'
            channels: [my_logger]

After this, I can access my looger with a dynamically created service named monolog.logger.my_logger

Answer 2

The MonologBundle logs everything using the same handlers for the whole framework. That means if one of your services needs to log to different handlers, you should create your own Logger/Handler and inject that in your service.

This could be an example config (in yaml):

services:
    my_logger:
        class: Symfony\Bridge\Monolog\Logger
        arguments: [soap]
        calls:
            - [pushHandler, [@my_handler]]

    my_handler:
        class: Monolog\Handler\StreamHandler
        # 200 = INFO, see Monolog::Logger for the values of log levels
        arguments: [%kernel.root_dir%/%kernel.environment%.soap.log, 200]

    soap_service:
        class: Your\Soap\Client
        arguments: [@my_logger]

I hope this clarifies it.

Update: as of symfony 2.1, you can also configure which channels receive which handlers, so you could alternatively do something like this:

services:
     soap_service:
         class: Your\Soap\Client
         arguments: [@logger]
         tags:
             - { name: monolog.logger, channel: soap }

Which creates a new soap channel (i.e. logger instance receiving all handlers), then to configure different handlers for this channel:

monolog:
    handlers:
        main:
            type: stream
            path: %kernel.root_dir%/%kernel.environment%.log
            level: error
            channels: [!soap]
        soap:
            type: stream
            path: %kernel.root_dir%/%kernel.environment%.soap.log
            level: info
            channels: [soap]

This means the main handler will receive everything but the soap channel, and the soap handler will receive only the soap channel. You could also remove the channels key on the main handler if you want your main log file to have everything, but also have a copy of only the soap logs separately. This brings a lot of flexibility, and as you see the channels is an array so you can list channels you want, or use the blacklist !name notation to exclude some and include everything else.

Answer 3

I had a similar problem and I chose to use the Monolog library directly instead of the Monolog service.

Monolog uses Monolog\Handler\StreamHandler to write to files. The github page has a simple example:

use Monolog\Logger;
use Monolog\Handler\StreamHandler;

// create a log channel
$log = new Logger('name');
$log->pushHandler(new StreamHandler('path/to/your.log', Logger::WARNING));

// add records to the log
$log->addWarning('Foo');
$log->addError('Bar');

It may be possible to still use the service and simply push a new handler (and pop it once you're done - otherwise you might inadvertently write more than you wanted to to your custom log) but I haven't tested this. Honestly it seemed easier just to use the library directly.