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flipt-client-ruby

README.md

Flipt Client Ruby

Gem Version

The flipt-client-ruby library contains the Ruby source code for the Flipt client-side evaluation client.

Installation

gem install flipt_client

How Does It Work?

The flipt-client-ruby library is a wrapper around the flipt-engine-ffi library.

All evaluation happens within the SDK, using the shared library built from the flipt-engine-ffi library.

Because the evaluation happens within the SDK, the SDKs can be used in environments where the Flipt server is not available or reachable after the initial data is fetched.

Data Fetching

Upon instantiation, the flipt-client-ruby library will fetch the flag state from the Flipt server and store it in memory. This means that the first time you use the SDK, it will make a request to the Flipt server.

Polling (Default)

By default, the SDK will poll the Flipt server for new flag state at a regular interval. This interval can be configured using the update_interval option when constructing a client. The default interval is 120 seconds.

Streaming (Flipt Cloud Only)

Flipt Cloud users can use the streaming fetch method to stream flag state changes from the Flipt server to the SDK.

When in streaming mode, the SDK will connect to the Flipt server and open a persistent connection that will remain open until the client is closed. The SDK will then receive flag state changes in real-time.

Supported Architectures

This SDK currently supports the following OSes/architectures:

  • Linux x86_64
  • Linux arm64
  • MacOS x86_64
  • MacOS arm64
  • Windows x86_64

Using System Libffi

If you are experiencing segfaults when using this gem, you may need to configure ffi to use the system libffi instead of the bundled one.

You can do this before installing the gem by running the following command:

gem install ffi -- --enable-system-libffi        # to install the gem manually
bundle config build.ffi --enable-system-libffi   # for bundle install

Usage

In your Ruby code you can import this client and use it as so:

require 'flipt_client'

# namespace is the first positional argument and is optional here and will have a value of "default" if not specified.
# opts is the second positional argument and is also optional, the structure is:
# {
#   "url": "http://localhost:8080",
#   "update_interval": 120,
#   "authentication": {
#     "client_token": "secret"
#   }
# }
#
# You can replace the url with where your upstream Flipt instance points to, the update interval for how long you are willing
# to wait for updated flag state, and the auth token if your Flipt instance requires it.
client = Flipt::EvaluationClient.new()
resp = client.evaluate_variant({ flag_key: 'buzz', entity_id: 'someentity', context: { fizz: 'buzz' } })

puts resp

Constructor Arguments

The Flipt::EvaluationClient constructor accepts two optional arguments:

  • namespace: The namespace to fetch flag state from. If not provided, the client will default to the default namespace.
  • opts: A hash that supports several options for the client. The structure is:
    • url: The URL of the upstream Flipt instance. If not provided, the client will default to http://localhost:8080.
    • update_interval: The interval (in seconds) in which to fetch new flag state. If not provided, the client will default to 120 seconds.
    • authentication: The authentication strategy to use when communicating with the upstream Flipt instance. If not provided, the client will default to no authentication. See the Authentication section for more information.
    • reference: The reference to use when fetching flag state. If not provided, reference will not be used.
    • fetch_mode: The fetch mode to use when fetching flag state. If not provided, the client will default to polling.

Authentication

The FliptEvaluationClient supports the following authentication strategies:

Load Test

  1. To run the load test, you'll need to have Flipt running locally. You can do this by running the following command from the root of the repository:

    docker run -d \
    -p 8080:8080 \
    -p 9000:9000 \
    flipt/flipt:latest

  2. You'll also need to have the flipt_client gem installed locally. See Installation above.

  3. In the Flipt UI (http://localhost:8080) you'll also need to create a new boolean flag with the key my-feature in the default namespace.

  4. You can then run the load test by running the following command from this folder:

    bundle exec ruby load_test.rb

Contributing

Contributions are welcome! Please feel free to open an issue or submit a Pull Request.

License

This project is licensed under the MIT License.