fibonacci

This example contains a very simple API server implemented with just the Crystal Standard Library. On any request, it looks for a query parameter n and, if that parameter exists, and is a positive number, the nth number in the Fibonacci Sequence will be calculated and returned. This

If the query appears to be malformed in any way, an error message is returned.

A secondard tool, load_generator, is also included. When ran, it will loop, sending random queries to the Fibonacci API server and displaying the results.

This application has been copied from an New Relic repo, where it was originally used to show how to instrument a Crystal app.

• https://newrelic.com/blog/how-to-relic/otel-crystal
• https://github.com/newrelic-experimental/mcv3-apps/tree/kh.add-crystal-example-20220412/Uninstrumented/crystal

Installation & Usage

If you have Crystal installed on your system, you can compile and run these apps directly. If you do not have Crystal installed, you can find your operating system on the Install page of the Crystal web site, and follow the instructions. Alternatively, if you have docker available, a Dockerfile is provided to run the examples.

If you are building and running the code manually, you can compile the server with the following command:

crystal build -p -s -t --release src/server.cr

A fibonacci binary will be placed in your directory when the code finishes compiling.

To build the load generator, you can use:

crystal build -p -s -t src/load_generator.cr

Then, to run then, using two different shells, execute:

./server

in one shell, and:

./load_generator

in the other.

Or, for a simple test, do the following:

curl http://127.0.0.1:5100/?n=37’

The answer should be 24157817, or 14930352 depending on how you count.

Contributing

1. Fork it (https://github.com/your-github-user/fibonacci/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Nick Brandaleone - creator and maintainer