Kazus

Kazus provides a simple logging helper. It accepts any amount or type of arguments and logs everything well readable, while including eventually given information like backtraces, validation errors of ActiveModel instances (the gem doesn't depend on rails, though) or the object's length (of an array or a hash). It is designed to not throw errors whatever the arguments are.

For example, lines like

Rails.logger.error "@statement has unexpected validation errors: #{@statement.errors.full_messages.inspect}"

can be replaced by

Kazus.log :error, "Unexpected validation errors", "@statement" => @statement

which logs

[KAZUS|error] Unexpected validation errors -- RELATED OBJECTS:       0.0| TITLE: @statement | CLASS: Statement | ERRORS: User must exist, body can't be blank | INSPECT: #<Statement id: nil, user_id: nil, body: nil, created_at: nil, updated_at: nil> | TO_S: #<Statement:0x007f9a971683c8> |0.0

or simply

Kazus.log @statement

to log

[KAZUS|debug] RELATED OBJECTS:       0| CLASS: Statement | ERRORS: User must exist, body can't be blank | INSPECT: #<Statement id: nil, user_id: nil, body: nil, created_at: nil, updated_at: nil> | TO_S: #<Statement:0x007faffcd962d8> |0

Run

$ gem install kazus

or add this line to your application's Gemfile

gem 'kazus'

and run $ bundle install.

You can configure kazus to use another logger than the default Logger. To do so, make sure to call Kazus.configure with a block, like

Kazus.configure do |config|
  config.logger = Rails.logger
end

to use Rails.logger, for example.

If you are using rails, you can simply run

$ rails generate kazus:install

to copy an initialzer file into config/initializers/.

The provisioned methods are:

Can be called with an arbitrary amount of arguments without raising an exception. It doesn't make sense to call it without arguments, though. It'll log a warning in this case.

If there's only one argument given, it will be interpreted as the incident description if it's a string or else as an object to be inspected. The log level will be set to debug in this case.

Else, if the first argument is a valid log level, which is one of

• 0, 1, 2, 3, 4 or 5

or

• :debug, :info, :warn, :error, :fatal or :unknown

or

• "debug", "info", "warn", "error", "fatal" or "unknown"

or

• "DEBUG", "INFO", "WARN", "ERROR", "FATAL" or "UNKNOWN"

it will be interpreted as - surprise - log level. If it's anything else, every argument, including the first, will be interpreted as objects to be inspected. The log level will then default to :debug.

If the second argument is a string (while the first argument is a valid log level), it will be interpreted as the incident description (which only has a meaning for formatting of the log message). If it's anything else, it will be interpreted as an object to be inspected as all following arguments are, too.

The third and any following argument will always be interpreted as objects to be inspected.

All messages include the sequence of letters [KAZUS|. I use this to parse the logs for important messages. If you want to parse for certain log levels, for example fatal, the pattern is [KAZUS|fatal]. Same goes for any other log level named above.

Does almost the same as Kazus.log but instead of using the configured logger simply uses puts, to log the inspection to STDOUT. Ideal for quick debugging purposes.

You can call Kazus.log with just an array for quick debugging purposes:

Kazus.log [1, "A"]

will output

[KAZUS|debug] RELATED OBJECTS:       0| CLASS: Array | COUNT: 2 | INSPECT: [1, "A"] |0

Or you can log an unexpected exception. Kazus includes the backtrace in such cases:

Kazus.log :fatal, "An exception was thrown unexpectedly", exception

will output

[KAZUS|fatal] An exception was thrown unexpectedly -- RELATED OBJECTS:       0| CLASS: Exception | INSPECT: #<Exception: ThisException> | TO_S: ThisException | BACKTRACE: /A/k/o/llad.rb ### /B/k/o/llad.rb |0

If the last given argument is a hash, kazus titles each value with its key:

Kazus.log "Number A" => 54, "Number B" => 32

will output

[KAZUS|debug] RELATED OBJECTS:       0.0| TITLE: Number A | CLASS: Fixnum | INSPECT: 54 |0.0       0.1| TITLE: Number B | CLASS: Fixnum | INSPECT: 32 |0.1

If you are using rails and you call Kazus.log with a model instance, its error messages get included in the logs:

statement = Statement.new
statement.valid? # Generate error messages

Kazus.log :info, nil, statement

will output

[KAZUS|info] RELATED OBJECTS:       0| CLASS: NilClass | INSPECT: nil |0       1| CLASS: Statement | ERRORS: User must exist, body can't be blank | INSPECT: #<Statement id: nil, user_id: nil, body: nil, created_at: nil, updated_at: nil> | TO_S: #<Statement:0x007fb108353318> |1

Bug reports and pull requests are welcome on GitHub at https://github.com/esBeee/kazus. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.