README.md
# CallLogger
A debugging tool that lets you log method usage.
[](https://travis-ci.org/mrzasa/call_logger)
[](https://codeclimate.com/github/mrzasa/call_logger/maintainability)
In the default setting, a method is logged before call with arguments and after the call with result and time call took (in seconds).
A message is also logged on execution error.
```
class Calculator
include CallLogger
log def times(a, b)
a*b
end
log def div(a, b)
a/b
end
log def slow_square(a)
sleep a
a * a
end
log_class def self.info(msg)
"Showing: #{msg}"
end
end
Calculator.new.times(3,4)
# Calculator#times(3, 4)
# Calculator#times => 6, [Took: 0.000011s]
# => 6
Calculator.new.div(3,0)
# Calculator#div(3, 0)
# Calculator#div !! divided by 0
# ZeroDivisionError: divided by 0
Calculator.info("hello!")
# Calculator.info(hello)
# Calculator.info => "Showing: hello", [Took: 0.000011s]
Calculator.new.slow_square(2)
# Calculator#slow_square(2)
# Calculator#slow_square => 4, [Took: 2.000117s]
```
## Installation
Add this line to your application's Gemfile:
```ruby
gem 'call_logger'
```
And then execute:
$ bundle
Or install it yourself as:
$ gem install call_logger
## Usage
### Wrapping a single method
Include it to a class being debugged and the prepend a method definition with `log`:
```
class Calculator
include CallLogger
log def times(a, b)
a*b
end
end
```
`.log` accepts method name, so you can pass it explicitly:
```
class Calculator
include CallLogger
def times(a, b)
a*b
end
log :times
end
```
If you want to log class method calls, prepend them with `.log_class`:
```
class Calculator
include CallLogger
log_class def self.times(a, b)
a*b
end
end
```
### Wrapping multiple methods
You can also pass multiple method names to `.log` and `.log_class` to wrap them all:
```
class Calculator
include CallLogger
log :times, :div
def times(a, b)
a*b
end
def div(a, b)
a/b
end
end
```
```
class Calculator
include CallLogger
log_class :times, :div
def self.times(a, b)
a*b
end
def self.div(a, b)
a/b
end
end
```
### Wrapping a block
You can wrap a block of code using `#log_block` (in instance methods) or `.log_block` (in class methods). Block parameters will not be logged though:
```
class Calculator
include CallLogger
def times(a, b)
log_block('multiply')
a*b
end
end
end
Calculator.new.times(3,4)
# multiply
# multiply => 6, [Took: 0.000011s]
# => 6
```
Block calls may be also logged without including `CallLogger` module with `CallLogger.log_block`:
```
log_block('multiply')
a*b
end
Calculator.new.times(3,4)
# multiply
# multiply => 6, [Took: 0.000011s]
# => 6
```
### Configuration
There are two pluggable components: `Logger` and `Formatter`. `Formatter` preperes messages to be printed and `Logger` sents them to the
output stream (whatever it is). This documentation uses default ones, but they can be easily configured:
```
::CallLogger.configure do |config|
config.logger = CustomLogger.new
config.formatter = CustomFormatter.new
end
```
* `Logger` should provide a `#call` method accepting a single paramter.
* `Formatter` should provide following methods:
* `#before(method, args)` - accepting method name and it's arguments; called before method execution
* `#after(method, result, seconds: nil)` - accepting method name, it's result and seconds took execution as a KV param; called after method execution
* `#error(method, exception)` - accepting method name and an exception; called when error is raised
## TODO
* [+] class methods
* [+] multiple method names
* [+] handle blocks
* [] logging all methods defined in the class
* [] doc: Rails integration
* [] doc: API docs
* [+] infra: travis
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
## Contributing
Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/call_logger.
## License
The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).