How to use CustomHealthCheck with health_check gem in ruby? - ruby-on-rails

Question

From the health_check official site, we know that it can add a config.add_custom_check block in the config file:
https://github.com/ianheggie/health_check
# Add one or more custom checks that return a blank string if ok, or an error message if there is an error
config.add_custom_check do
CustomHealthCheck.perform_check # any code that returns blank on success and non blank string upon failure
end
# Add another custom check with a name, so you can call just specific custom checks. This can also be run using
# the standard 'custom' check.
# You can define multiple tests under the same name - they will be run one after the other.
config.add_custom_check('sometest') do
CustomHealthCheck.perform_another_check # any code that returns blank on success and non blank string upon failure
end
But about the CustomHealthCheck class, how to define it?
For okcomputer gem, it offers a way like this:
https://github.com/sportngin/okcomputer
# config/initializers/okcomputer.rb
class MyCustomCheck < OkComputer::Check
def check
if rand(10).even?
mark_message "Even is great!"
else
mark_failure
mark_message "We don't like odd numbers"
end
end
end
OkComputer::Registry.register "check_for_odds", MyCustomCheck.new
Didn't find the usage about health_check gem.
Update
I have tried:
Add these source in the config/initializers/health_check.rb file:
class CustomHealthCheck
def perform_check
if rand(10).even?
p "Even is great!"
else
p "We don't like odd numbers"
end
end
end
HealthCheck.setup do |config|
...
Run curl -v localhost:3000/health_check.json, got:
{"healthy":false,"message":"health_check failed: undefined method `perform_check' for CustomHealthCheck:Class"}%
Update 2
Edited source in config/initializers/health_check.rb:
class CustomHealthCheck
def self.perform_check
p 'OK'
end
end
HealthCheck.setup do |config|
...
Got:
{"healthy":false,"message":"health_check failed: OK"}%

Answer 1

Success is defined by returning an empty or blank string. Right now your perform_check always returns the string "OK" which will be seen as failure.
Try this to get a passing health check:
class CustomHealthCheck
def self.perform_check
everything_is_good = true # or call some method to do more elaborate checking
return everything_is_good ? "" : "We've got Problems"
end
end