feat(usage): at-least-once and dynamic sampling

[charcoalyy]

Context

GraphQL Hive Client has an option for at least once sampling that is not included in the ruby gem. As a side, this option also allows dynamic sampling via passing in a function.

Currently, graphql-ruby-hive only allows for a fixed sampling rate. With this update, you can input either a fixed sampling rate or a dynamic sampler. You can also choose to sample all distinct operations at least once. See new README.md for specific configuration details.

Changes

• BasicSampler created for fixed sampling rates, with the option to sample all operations at least once
• DynamicSampler created for dynamic sampling, with the option to sample all operations at least once
• Sampler created to manage sampling logic for UsageReporter to use
• passing a sampling rate to collect_usage_sampling still works, but will also log a deprecated field warning

Testing

Unit tests have been included for all Sampler classes and updated for UsageReporter.

This gem was tested locally with the following cases:

• sample rate (both deprecated and updated version)
• dynamic sampler
• sample rate with at least once sampling
• dynamic sampler with at least once sampling
• sample rate with at least once sampling and custom key generator
• dynamic sampler with at least once sampling and custom key generator

Cases were consistent with behaviour documented in README.

[aryascripts]

Leaving as a comment because I don't disagree with any of the code written here strongly, but I do have some suggestions about clarifying the config arguments better.

And, some discussion on log levels if we have wrong configs. Just wondering about others' thoughts on this as well!

[aryascripts]

This is great! Ty for all the fixes after comments.

[rperryng]

Looks great!

My only thought was that if we're introducing a "new" API for configuration that we should try and match the official NodeJS client as closely as possible, but I see this would conflict with some other feedback related to some values being multiple types (e.g. boolean and function) - which I agree is maybe a bit confusing as I don't think this is as common in ruby code (probably due to lack of strong type-safety). So looks good to me.