journald-native/README.md

# journald-native

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A systemd-journal native logging lib wrapper.
[See sd-journal help for more info](http://www.freedesktop.org/software/systemd/man/sd_journal_print.html)

## Installation

Run

```sh
gem install journald-native
```

or add

```ruby
gem 'journald-native', '~> 1.0'
```

to your Gemfile.

Please note that you need a systemd development package installed in your system like `systemd-devel` in Fedora, `libsystemd-dev` in Debian, also may be a separate package for journal in older systems like `libsystemd-journal-dev`.

## Usage

```ruby
require 'journald/native'
```

### Constants

Constants are used to denote a log level

Available constants:

```ruby
Journald::LOG_EMERG     # system is unusable
Journald::LOG_ALERT     # action must be taken immediately
Journald::LOG_CRIT      # critical conditions
Journald::LOG_ERR       # error conditions
Journald::LOG_WARNING   # warning conditions
Journald::LOG_NOTICE    # normal but significant condition
Journald::LOG_INFO      # informational
Journald::LOG_DEBUG     # debug-level messages
```

systemd-journal uses syslog constants to denote level therefore they are equal to those of the Syslog module,
e.g. ```Journald::LOG_WARNING == Syslog::LOG_WARNING```.
[See syslog man page for more info](http://man7.org/linux/man-pages/man3/syslog.3.html)

### Methods

Methods of Journald::Native class wrap systemd-journal calls.
[See sd-journal help for more info](http://www.freedesktop.org/software/systemd/man/sd_journal_print.html)

```ruby
Journald::Native.send "MESSAGE=message", "PRIORITY=#{Journald::LOG_WARNING}"
Journald::Native.print Journald::LOG_WARNING, "message"
Journald::Native.perror "message"
```

It is not recommended to use ```print``` and ```perror``` as you may get exception if your string contains
```'\0'``` byte due to C zero-terminated string format. On the contrary ```send``` uses binary buffers and
does not have this shortcoming.

### License

The gem is available as open source under the terms of the GNU Lesser General Public License, version 2.1
or later.