FFM-4043 - Add checks for nested pre req flags (harness#95)

* Change 'number' to 'int' input on number variations

* Check prereq flags for nested prereqs, update example app

* simple refactor

Author: stephenmcconkey

evaluation/feature.go

@@ -304,6 +304,13 @@ func prereqsSatisfied(fc FeatureConfig, target *Target, flags map[string]Feature
 			continue
 		}
 
+		if prereqFlag.Prerequisites != nil {
+			res := checkPreReqsForPreReqs(prereqFlag.Prerequisites, flags, target)
+			if !res {
+				return false
+			}
+		}
+
 		variationToMatch := prereqFlag.Variations.FindByIdentifier(prereqFlag.GetVariationName(target))
 
 		if pre.Feature == prereqFlag.Feature {
@@ -540,3 +547,29 @@ type WeightedVariation struct {
 	Variation string
 	Weight    int
 }
+
+func checkPreReqsForPreReqs(preReqFlagPreReqs []Prerequisite, flags map[string]FeatureConfig, target *Target) bool {
+	for _, preReq := range preReqFlagPreReqs {
+		nestedPreReq, ok := flags[preReq.Feature]
+		if !ok {
+			continue
+		}
+
+		if len(nestedPreReq.Prerequisites) > 0 {
+			nested := checkPreReqsForPreReqs(nestedPreReq.Prerequisites, flags, target)
+			if !nested {
+				return false
+			}
+		}
+
+		preReqVariationToMatch := nestedPreReq.Variations.FindByIdentifier(nestedPreReq.GetVariationName(target))
+		if preReq.Feature == nestedPreReq.Feature {
+			for _, variation := range preReq.Variations {
+				if variation != preReqVariationToMatch.Value {
+					return false
+				}
+			}
+		}
+	}
+	return true
+}

evaluation/feature_test.go

@@ -1546,3 +1546,203 @@ func TestFeatureConfig_prereqsSatisfied(t *testing.T) {
 		})
 	}
 }
+
+func TestCheckPreReqsForPreReqs(t *testing.T) {
+	trueVariation := Variation{
+		Name:       stringPtr("True"),
+		Value:      "true",
+		Identifier: "true",
+	}
+
+	falseVariation := Variation{
+		Name:       stringPtr("False"),
+		Value:      "false",
+		Identifier: "false",
+	}
+
+	blueVariation := Variation{
+		Name:       stringPtr("blue"),
+		Value:      "blue",
+		Identifier: "blue",
+	}
+
+	redVariation := Variation{
+		Name:       stringPtr("red"),
+		Value:      "red",
+		Identifier: "red",
+	}
+
+	flags := map[string]FeatureConfig{
+		"flag1": {
+			DefaultServe: Serve{
+				Variation: stringPtr("true"),
+			},
+			Environment:          "dev",
+			Feature:              "flag1",
+			Kind:                 "boolean",
+			OffVariation:         "false",
+			Prerequisites:        nil,
+			Project:              "default",
+			Rules:                nil,
+			State:                "on",
+			VariationToTargetMap: nil,
+			Variations: Variations{
+				trueVariation, falseVariation,
+			},
+			Segments: nil,
+		},
+		"flag2": {
+			DefaultServe: Serve{
+				Variation: stringPtr("true"),
+			},
+			Environment:  "dev",
+			Feature:      "flag2",
+			Kind:         "boolean",
+			OffVariation: "false",
+			Prerequisites: []Prerequisite{
+				{Feature: "flag1",
+					Variations: []string{"true"},
+				},
+			},
+			Project:              "default",
+			Rules:                nil,
+			State:                "on",
+			VariationToTargetMap: nil,
+			Variations: Variations{
+				trueVariation, falseVariation,
+			},
+			Segments: nil,
+		},
+		"flag3": {
+			DefaultServe: Serve{
+				Variation: stringPtr("true"),
+			},
+			Environment:  "dev",
+			Feature:      "flag3",
+			Kind:         "boolean",
+			OffVariation: "false",
+			Prerequisites: []Prerequisite{
+				{Feature: "flag2",
+					Variations: []string{"true"},
+				},
+			},
+			Project:              "default",
+			Rules:                nil,
+			State:                "on",
+			VariationToTargetMap: nil,
+			Variations: Variations{
+				trueVariation, falseVariation,
+			},
+			Segments: nil,
+		},
+		"mv1": {
+			DefaultServe: Serve{
+				Variation: stringPtr("red"),
+			},
+			Environment:  "dev",
+			Feature:      "mv1",
+			Kind:         "string",
+			OffVariation: "blue",
+			Prerequisites: []Prerequisite{
+				{Feature: "flag1",
+					Variations: []string{"true"},
+				},
+			},
+			Project:              "default",
+			Rules:                nil,
+			State:                "on",
+			VariationToTargetMap: nil,
+			Variations: Variations{
+				redVariation, blueVariation,
+			},
+			Segments: nil,
+		},
+	}
+	tests := []struct {
+		name              string
+		expected          bool
+		preReqFlagPreReqs []Prerequisite
+		flags             map[string]FeatureConfig
+		target            *Target
+	}{
+		{
+			name:              "Given I have no preReqFlagPreReqs",
+			expected:          true,
+			flags:             nil,
+			preReqFlagPreReqs: nil,
+			target:            nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs that has no nested preregs that will match",
+			expected: true,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "flag1",
+					Variations: []string{"true"},
+				},
+			},
+			target: nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs that has no nested prereqs that will not match",
+			expected: false,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "flag1",
+					Variations: []string{"false"},
+				},
+			},
+			target: nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs that has nested prereqs that will match i.e. flag 3 depends on flag 2, which depends on flag 1",
+			expected: true,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "flag3",
+					Variations: []string{"true"},
+				},
+			},
+			target: nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs that has nested prereqs that will not match",
+			expected: false,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "flag3",
+					Variations: []string{"false"},
+				},
+			},
+			target: nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs of a mv flag that has nested prereqs that will not match",
+			expected: false,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "mv1",
+					Variations: []string{"blue"},
+				},
+			},
+			target: nil,
+		},
+		{
+			name:     "Given I have a preReqFlagPreReqs of a mv flag that has nested prereqs that will match",
+			expected: true,
+			flags:    flags,
+			preReqFlagPreReqs: []Prerequisite{
+				{Feature: "mv1",
+					Variations: []string{"red"},
+				},
+			},
+			target: nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.expected, checkPreReqsForPreReqs(tt.preReqFlagPreReqs, tt.flags, tt.target))
+		})
+	}
+}

examples/getting_started.go

@@ -11,24 +11,24 @@ import (
 
 var (
 	flagName string = getEnvOrDefault("FF_FLAG_NAME", "harnessappdemodarkmode")
-	apiKey   string = getEnvOrDefault("FF_API_KEY", "changeme")
+	sdkKey   string = getEnvOrDefault("FF_API_KEY", "changeme")
 )
 
 func main() {
 	log.Println("Harness SDK Getting Started")
 
 	// Create a feature flag client
-	client, err := harness.NewCfClient(apiKey)
+	client, err := harness.NewCfClient(sdkKey)
 	if err != nil {
 		log.Fatalf("could not connect to CF servers %s\n", err)
 	}
 	defer func() { client.Close() }()
 
 	// Create a target (different targets can get different results based on rules)
 	target := evaluation.Target{
-		Identifier: "golangsdk",
-		Name:       "GolangSDK",
-		Attributes: &map[string]interface{}{"location": "emea"},
+		Identifier: "HT_1",
+		Name:       "Harness_Target_1",
+		Attributes: &map[string]interface{}{"email": "[email protected]"},
 	}
 
 	// Loop forever reporting the state of the flag