Simple logging-framework for Arduino supporting levels and handlers.

It provides a static Logger instance that has static Print instances as members. These members are debug, info, warning and error and represent preconfigured log targets for the available log levels.

As these are Print instances, you can use them as drop-in-replacement for Serial. For example instead of Serial.println("Hello") you just write Logger.debug.println("Hello"). This will print the String Hello to all streams that are configured for DEBUG.

To configure a Print instance for a log level you simply add it as log handler. For example, to log all log messages to Serial you need to call:

Logger.addHandler(Logger.DEBUG, Serial);

Log levels are including. That means, that when you configure a handler for a certain level, you'll get everything up to this level. The available levels are: ERROR, WARNING, INFO, DEBUG with debug the highest level. So if you configure your Handler for DEBUG, you'll get messages for all levels. If you configure for ERROR, you'll get only error messages.

The template LineBufferProxy implements a simple proxy to buffer messages and send them line- or messagewise to some target. Simply inherit from it and implement the flush() method. It is called when either the internal buffer is full or the Sep char was found. The String it gets is always null terminated. The size() can be used if the length is needed. So you can save the time of a strlen().