Logging

The Util class includes a static property named logLevel which can be used to control the sending of log messages to a log. This property should be given one of four values defined by the ceLTIc\LTI\Enum\LogLevel enumeration (or constants in the Util class for version 4 or earlier). One of four values should be used:

Enumeration value	Description
LogLevel::None	No log messages are recorded (this is the default setting)
LogLevel::Error	Only logs of errors are recorded
LogLevel::Info	All error and information log messages are recorded
LogLevel::Debug	All log messages are recorded

In version 4 (and earlier), use one of the constants defined in the ceLTIc\LTI\Util class:

Constant name	Description
LOGLEVEL_NONE	No log messages are recorded (this is the default setting)
LOGLEVEL_ERROR	Only logs of errors are recorded
LOGLEVEL_INFO	All error and information log messages are recorded
LOGLEVEL_DEBUG	All log messages are recorded

By default, no messages are logged. To change this include a line such as the following before any messages or service requests are processed:

use ceLTIc\LTI\Enum\LogLevel;

...

Util::$logLevel = LogLevel::Debug;

or, for version 4 and earlier:

use ceLTIc\LTI\Util;

...

Util::$logLevel = Util::LOGLEVEL_DEBUG;

The following methods include logging events:

• Tool->handleRequest:
  • details of the request received (LogLevel::Info)
  • reason for any error with the request (LogLevel::Error)
• 'Http\HttpMessage->send' (LogLevel::Info when successful, LogLevel::Error when unsuccessful):
  • details of the request being sent (URL and POST parameters or message body)
  • the response received (headers and any message body)
• DataConnector\DataConnector sub-classes:
  • SQL statements executed (LogLevel::Debug when successful, LogLevel::Error when unsuccessful)

Debug-level logging is also enabled when the debugMode property of the Tool or Platform object in use is set to true. When enabled, this setting will override the currently defined log level. See the Usage section for more information.

Logger client

By default log messages are sent to the PHP error log (using the error_log function). However, an alternative logger client can be specified by calling the Util::setLoggerClient method. The alternative logger client must be PSR-3 compliant. For example, the following code illustrates how Monolog could be used to send logs to a specified file:

use ceLTIc\LTI\Util;
...
$logFile = ini_get('error_log');  // Specify location of log file
$loggerClient = new Monolog\Logger('MyLogger');
$streamHandler = new Monolog\Handler\StreamHandler($logFile);
$streamHandler->setFormatter(new Monolog\Formatter\LineFormatter("[%datetime%] [%context.ip%] [%level_name%] %message%\n", 'd-M-Y H:i:s T', true));
$loggerClient->pushHandler($streamHandler);
Util::setLoggerClient($loggerClient);
...

An ip property of the logger context is available for inclusion in the formatting of a log entry (as in the above example); it is set to the IP address of the user.

(See the documentation for the logging client being used for further information.)