[FEATURE] flagd bulk evaluation

[toddbaert]

Requirements

In order to support synchronous evaluation (something particularly important for client use cases), we need a bulk evaluation endpoint in flagd. The endpoint would accept a context and evaluate all configured flags with that context. The returned result should be a map of flagKey: resolutionDetails.

• update schema ([FEATURE] bulk evaluation  flagd-schemas#63)
• implement function
• add tests
• add documentation

Example curl:

curl -X POST "localhost:8013/schema.v1.Service/ResolveAll" -d '{"context":{"email": "foo@bar.com"}}' -H "Content-Type: application/json"

{
   "flag1":{
      "value":"#0000FF",
      "reason":"TARGETING_MATCH",
      "variant":"blue"
   },
   "flag2":{
      "value":false,
      "reason":"STATIC",
      "variant":"on"
   }
}

Things to consider:

• possible enhancements in the future to allow an array of flag keys to evaluate, instead of all
• should we include additional metadata such as flag type to aid in parsing?

[beeme1mr]

Depends on open-feature/open-feature-operator#291