Current version: 1.0.1

This is a lightweight MIT-licensed attribute-based logging static library written in C++11.

The motivations and basic design are covered in the functional spec (doc/funspec.rst). Using the library is covered in the user manual (doc/manual.rst).

The source may be obtained via Git:

git clone https://git.kyleisom.net/lib/klogger
git clone https://github.com/kisom/klogger

If cloned from Git, the package may be built using the autobuild.sh script supplied in the root directory. The standard ./configure && make && sudo make install dance can be used as well, once the configure script has been generated with autoreconf -i.

Log messages consist of four components:

1. The level attaches a notion of priority to the log message.
2. The actor is used to specify which component is generating the log message. This could be the program name, or it could be a specific component inside the system.
3. The event is a short message indicating what happened. This is most like the traditional log message.
4. The attributes are an optional set of key-value string pairs that provide additional information.

Additionally, each log message has an associated timestamp. For the text-based logs, this is "%FT%T%z"; for the binary logs, this is a 64-bit Unix timestamp. An example text-based timestamp might look like

[2016-03-27T20:59:27-0700] [INFO] [actor:server event:request received] client=192.168.2.5 request-size=839

Note that this is organised in a manner that facilitates parsing:

/\[(\d{4}-\d{3}-\d{2}T\d{2}:\d{2}:\d{2}[+-]\d{4})\] \[(\w+\)]\) \[actor:(.+?) event:(.+?)\]/

will cover the header:

• $1 contains the timestamp
• $2 contains the level
• $3 contains the actor
• $4 contains the event

The library revolves around the Logger virtual class. There are several implementations:

• ConsoleLogger: writes DEBUG and INFO messages to standard output,

  and other messages to standard error. The constructor takes no arguments. See src/console_test.cc

• FileLogger: writes DEBUG and INFO messages to a log file, and other messages to an error log file. There are two constructors: the first takes a single filename as an argument; the error log and the log file are the same file. Alternatively, separate log files can be specified. See src/file_test.cc.
• Syslogger: writes logs to syslog. See src/syslog_test.cc.

• BinLogger: operates similarly to FileLogger except that

  logs are written in a binary format.

The user's manual is in doc/manual.rst.

This is the src/console_test.cc program:

#include <cstdlib>
#include <map>
#include <string>

#include <klogger/console.hh>


int
main(int argc, char *argv[])
{
        std::string                             name = std::string(argv[0]);
        klog::ConsoleLogger                     console(name);
        std::map<std::string, std::string>      args;

        if (!console.good()) {
                ::abort();
        }

        console.debug("main", "starts");

        for (int i = 1; i < argc; i++) {
                auto        k = "argv[" + std::to_string(i) + "]";
                args[k] = std::string(argv[i]);
        }

        console.info("main", "starts", args);
        console.warn("main", "depleted", {{"args", std::to_string(argc)}});
        console.fatal("main", "ends");
}

Copyright (c) 2016 Kyle Isom <[email protected]>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.