feat: support flag metadata (#1476)

- Adds functionality to return flag metadata as part of the response.

Signed-off-by: Aasif Khan <aasifk106@gmail.com>

core/pkg/evaluator/json.go

@@ -327,6 +327,13 @@ func (je *Resolver) evaluateVariant(ctx context.Context, reqID string, flagKey s
 		metadata[SelectorMetadataKey] = selector
 	}
 
+	for key, value := range flag.Metadata {
+		// If value is not nil or empty, copy to metadata
+		if value != nil {
+			metadata[key] = value
+		}
+	}
+
 	if flag.State == Disabled {
 		je.Logger.DebugWithID(reqID, fmt.Sprintf("requested flag is disabled: %s", flagKey))
 		return "", flag.Variants, model.ErrorReason, metadata, errors.New(model.FlagDisabledErrorCode)
@@ -460,11 +467,28 @@ func configToFlags(log *logger.Logger, config string, newFlags *Flags) error {
 		return fmt.Errorf("transposing evaluators: %w", err)
 	}
 
-	err = json.Unmarshal([]byte(transposedConfig), &newFlags)
+	var configData ConfigWithMetadata
+	err = json.Unmarshal([]byte(transposedConfig), &configData)
 	if err != nil {
 		return fmt.Errorf("unmarshalling provided configurations: %w", err)
 	}
 
+	// Assign the flags from the unmarshalled config to the newFlags struct
+	newFlags.Flags = configData.Flags
+
+	// Assign metadata as a map to each flag's metadata
+	for key, flag := range newFlags.Flags {
+		if flag.Metadata == nil {
+			flag.Metadata = make(map[string]interface{})
+		}
+		for metaKey, metaValue := range configData.Metadata {
+			if _, exists := flag.Metadata[metaKey]; !exists {
+				flag.Metadata[metaKey] = metaValue
+			}
+		}
+		newFlags.Flags[key] = flag
+	}
+
 	return validateDefaultVariants(newFlags)
 }
 

core/pkg/evaluator/json_model.go

@@ -10,6 +10,11 @@ type Evaluators struct {
 	Evaluators map[string]json.RawMessage `json:"$evaluators"`
 }
 
+type ConfigWithMetadata struct {
+	Flags    map[string]model.Flag  `json:"flags"`
+	Metadata map[string]interface{} `json:"metadata"`
+}
+
 type Flags struct {
 	Flags map[string]model.Flag `json:"flags"`
 }

core/pkg/evaluator/json_test.go

@@ -1184,6 +1184,222 @@ func TestState_Evaluator(t *testing.T) {
 			expectedError:  true,
 			expectedResync: false,
 		},
+		"flag metadata": {
+			inputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": 1
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "targeting": {
+							"if": [
+							  {
+								"$ref": "emailWithFaas"
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"$evaluators": {
+						"emailWithFaas": {
+							  "in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+						}
+  					}
+				}
+			`,
+			inputSyncType: sync.ALL,
+			expectedOutputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": 1
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "source":"",
+						  "selector":"",
+						  "targeting": {
+							"if": [
+							  {
+								"in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"flagSources":null
+				}
+			`,
+		},
+		"flagSet and flag metadata": {
+			inputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": "sso/dev",
+							"version": "1.0.0"
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "targeting": {
+							"if": [
+							  {
+								"$ref": "emailWithFaas"
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"metadata": {
+						"flagSetId": "test",
+						"flagSetVersion": "1"
+					},
+					"$evaluators": {
+						"emailWithFaas": {
+							  "in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+						}
+  					}
+				}
+			`,
+			inputSyncType: sync.ALL,
+			expectedOutputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": "sso/dev",
+							"version": "1.0.0",
+							"flagSetId": "test",
+                            "flagSetVersion": "1"
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "source":"",
+						  "selector":"",
+						  "targeting": {
+							"if": [
+							  {
+								"in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"flagSources":null
+				}
+			`,
+		},
+		"flag metadata priority": {
+			inputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": "sso/dev",
+							"version": "1.0.0"
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "targeting": {
+							"if": [
+							  {
+								"$ref": "emailWithFaas"
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"metadata": {
+						"id": "test",
+						"flagSetVersion": "1"
+					},
+					"$evaluators": {
+						"emailWithFaas": {
+							  "in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+						}
+  					}
+				}
+			`,
+			inputSyncType: sync.ALL,
+			expectedOutputState: `
+				{
+  					"flags": {
+						"fibAlgo": {
+						  "variants": {
+							"recursive": "recursive",
+							"memo": "memo",
+							"loop": "loop",
+							"binet": "binet"
+						  },
+						  "metadata": {
+							"id": "sso/dev",
+							"version": "1.0.0",
+                            "flagSetVersion": "1"
+						  },
+						  "defaultVariant": "recursive",
+						  "state": "ENABLED",
+						  "source":"",
+						  "selector":"",
+						  "targeting": {
+							"if": [
+							  {
+								"in": ["@faas.com", {
+								"var": ["email"]
+							  }]
+							  }, "binet", null
+							]
+						  }
+    					}
+					},
+					"flagSources":null
+				}
+			`,
+		},
 	}
 
 	for name, tt := range tests {

core/pkg/model/flag.go

@@ -9,6 +9,7 @@ type Flag struct {
 	Targeting      json.RawMessage        `json:"targeting,omitempty"`
 	Source         string                 `json:"source"`
 	Selector       string                 `json:"selector"`
+	Metadata       map[string]interface{} `json:"metadata,omitempty"`
 }
 
 type Evaluators struct {

core/pkg/store/flags.go

@@ -21,7 +21,8 @@ type Flags struct {
 	mx             sync.RWMutex
 	Flags          map[string]model.Flag `json:"flags"`
 	FlagSources    []string
-	SourceMetadata map[string]SourceDetails
+	SourceMetadata map[string]SourceDetails `json:"sourceMetadata,omitempty"`
+	Metadata       map[string]interface{}   `json:"metadata,omitempty"`
 }
 
 type SourceDetails struct {