Log Vala

Log Vala is a Vala library that provides logging capabilities for applications. It allows developers to easily log messages of varying levels, such as debug, informational, warning, and error.

In order to use Log Vala, developers need to instantiate a logger and configure it with a set of parameters. The most common parameters include the log level, output target (e.g., console, file), and log format.

Features

Some of the key features of Log Vala include:

• Different log levels: Debug, Info, Warning, Error
• Multiple output targets: Console, File
• Configurable log format
• Thread-safe logging
• Ability to filter and route log messages based on severity or tags

Getting Started

Installation

Log Vala can be installed via Vala Package Manager (VPM) with the following command:

vpm install log-vala

Usage

To use Log Vala in your Vala application, you will need to do the following:

1. Include the Log Vala library in your code:

using Log;

2. Instantiate a logger with a specific name:

var logger = new Logger ("my-application");

3. Configure the logger with a set of parameters:

Log.Config.set_logger_level (logger.name, LogLevel.DEBUG);
Log.Config.set_format (logger.name, "%L [%T] %M");
Log.Config.add_output (logger.name, LogOutput.CONSOLE);

4. Use the logger to log messages:

logger.debug ("This is a debug message.");
logger.info ("This is an informational message.");
logger.warning ("This is a warning message.");
logger.error ("This is an error message.");

Configuration

Log Vala allows you to configure various aspects of log messages, including the log level, format, and output targets.

Log Level

Log levels include DEBUG, INFO, WARNING, and ERROR. By default, the log level is set to WARNING, which means that only warning and error messages are logged. You can set the log level to a different value using the following code:

Log.Config.set_logger_level (logger.name, LogLevel.DEBUG);

Format

You can specify the format of log messages using string templates. For example, the following format string will output the log severity, logger name, and message:

Log.Config.set_format (logger.name, "%L [%T] %M");

Output Targets

You can specify one or more output targets for log messages, including the console and a file. For example, the following code configures the logger to output messages to the console:

Log.Config.add_output (logger.name, LogOutput.CONSOLE);

Filtering and Routing

Log Vala also allows you to filter and route log messages based on severity or tags. This can be useful if you want to send certain types of messages to different output targets or if you want to ignore certain types of messages altogether.

Filtering by Severity

You can filter log messages based on severity by specifying a range of log levels. For example, the following code will only output messages of severity WARNING or higher:

Log.Config.add_filter (logger.name, LogLevel.WARNING, LogLevel.ERROR, LogOutput.CONSOLE);

Filtering by Tags

You can also filter log messages based on tags. Tags are arbitrary strings that can be associated with log messages. For example, you could associate the tag "database" with log messages related to database operations. The following code will output only messages that have the "database" tag:

Log.Config.add_filter_tag (logger.name, "database");

Conclusion

Log Vala is a powerful tool for logging messages of varying levels in your Vala application. By using Log Vala, you can easily configure and customize your logs to capture the information you need while ignoring the messages you don't. We hope that this guide has been helpful in getting you started with Log Vala!