feat: poc for flagd as a crd proxy

[Kavindu-Dodan]

This PR

fixes #411 and introduce a proposed implementation of flagd server deployment.

How to run ?

Start server

Use the new command server with the required parameters. Consider checking auto-generated documentation [1].

To start a non-TLS server with default address (localhost:9090) binding : go run main.go server --source <K8s CRD>

ex: go run main.go server --source core.openfeature.dev/test/test

To start TLS enabled server default address (localhost:9090) binding : go run main.go server --source <K8s CRD> -s -c <cert> -k <cert_key>

ex: go run main.go server --source core.openfeature.dev/test/test -s -c server.crt -k server.key

Start flagd (client)

Once flagd server is up and running, start flagd in provider mode and connect to grpc stram,

go run main.go start --uri grpc://localhost:9090 --debug.

You can run multiple flagd instances to verify server behavior,

go run main.go start --uri grpc://localhost:9090 --debug -p 8023 -m 8024

NOTE - Flagd TLS connectivity is still pending #398

Components

Following diagram shows high-level implementation,

[1] - https://github.com/open-feature/flagd/blob/62dd7bba1dcdf38b56f48a284703590b6dc4e21f/docs/configuration/flagd_server.md

[codecov]

Codecov Report

Merging #421 (62dd7bb) into main (33413f2) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #421   +/-   ##
=======================================
  Coverage   63.92%   63.92%           
=======================================
  Files          11       11           
  Lines        1325     1325           
=======================================
  Hits          847      847           
  Misses        428      428           
  Partials       50       50           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[Kavindu-Dodan]

Closing with focused project - https://github.com/orgs/open-feature/projects/8