Fixed t3c for layered profile order issue

CHANGELOG.md

@@ -95,6 +95,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - [#6775](https://github.com/apache/trafficcontrol/issues/6775) *Traffic Ops* Invalid "orgServerFqdn" in Delivery Service creation/update causes Internal Server Error
 - [#6695](https://github.com/apache/trafficcontrol/issues/6695) *Traffic Control Cache Config (t3c)* Directory creation was erroneously reporting an error when actually succeeding.
 - [#7411](https://github.com/apache/trafficcontrol/pull/7411) *Traffic Control Cache Config (t3c)* Fixed issue with wrong parent ordering with MSO non-topology delivery services.
+- [#7425](https://github.com/apache/trafficcontrol/pull/7425) *Traffic Control Cache Config (t3c)* Fixed issue with layered profile iteration being done in the wrong order.
 
 ## [7.0.0] - 2022-07-19
 ### Added

lib/go-atscfg/atscfg.go

@@ -848,13 +848,13 @@ func layerProfilesFromMap(profileNames []string, params []parameterWithProfilesM
 	}
 
 	layeredParamMap := map[ParamKey]tc.Parameter{}
-
-	for _, profileName := range profileNames {
-		profileParams := allProfileParams[profileName]
+	// profileNames is ordered, we need to iterate through this backwards
+	// because we need subsequent params on other profiles to override previous ones,
+	// this will provide the proper "layering" that we want.
+	for i := len(profileNames) - 1; i >= 0; i-- {
+		profileParams := allProfileParams[profileNames[i]]
 		for _, param := range profileParams {
 			paramkey := getParamKey(param)
-			// because profileNames is ordered, this will cause subsequent params
-			// on other profiles to override previous ones, "layering" like we want.
 			layeredParamMap[paramkey] = param
 		}
 	}

lib/go-atscfg/atscfg_test.go

@@ -185,18 +185,21 @@ func TestLayerProfiles(t *testing.T) {
 	}
 
 	// per the params, on the layered profiles "FOO,BAR,BAZ" (in that order):
-	// (1) beta in BAR should override alpha FOO,
-	//    because they share the ConfigFile+Name key and BAR is later in the layering
-	// (2) gamma should be added, but not override
+	// we iterate through params in reverse order because FOO will have the highest priority
+	// then BAR then BAZ, any duplicate params that exist with the same ConfigFile+Name
+	// in subsequent profiles can be overwritten by the next higher profile
+	// (1) alpha in FOO, should override beta in BAR
+	//    because they share the ConfigFile+Name key and FOO is later in the layering
+	// (2) gamma should be added, but not overridden
 	//    because the key is ConfigFile+Name, which isn't on any previous profile
-	// (3) epsilon in BAZ should override delta in BAR
-	//    because they share the ConfigFile+Name key and BAZ is later in the layering
+	// (3) delta in BAR should override epsilon in BAZ
+	//    because they share the ConfigFile+Name key and BAR is later in the layering
 	//    - this tests the parameters being in a different order than (1)
 	// (4) zeta should be added, but not override
 	//    because the key is ConfigFile+Name, which isn't on any previous profile
 	//    - this tests the name matching but not config file, reverse of (2).
-	// (5) theta in BAZ should override eta and iota in FOO and BAR
-	//    because they share the ConfigFile+Name key and BAZ is last in the layering
+	// (5) iota in FOO should override theta in BAZ and eta and BAR
+	//    because they share the ConfigFile+Name key and FOO is last in the layering
 	//    - this tests multiple overrides
 
 	layeredParams, err := LayerProfiles(profileNames, allParams)
@@ -209,32 +212,32 @@ func TestLayerProfiles(t *testing.T) {
 		vals[param.Value] = struct{}{}
 	}
 
-	if _, ok := vals["alpha"]; ok {
-		t.Errorf("expected: param 'beta' to override 'alpha', actual: alpha in layered parameters")
+	if _, ok := vals["beta"]; ok {
+		t.Errorf("expected: param 'alpha' to override 'beta', actual: beta in layered parameters")
 	}
-	if _, ok := vals["beta"]; !ok {
-		t.Errorf("expected: param 'beta' to override 'alpha', actual: beta not in layered parameters")
+	if _, ok := vals["alpha"]; !ok {
+		t.Errorf("expected: param 'alpha' to override 'beta', actual: alpha not in layered parameters")
 	}
 	if _, ok := vals["gamma"]; !ok {
 		t.Errorf("expected: param 'gamma' with no ConfigFile+Name in another profile to be in layered parameters, actual: gamma not in layered parameters")
 	}
-	if _, ok := vals["delta"]; ok {
-		t.Errorf("expected: param 'epsilon' to override 'delta' in prior profile, actual: delta in layered parameters")
+	if _, ok := vals["epsilon"]; ok {
+		t.Errorf("expected: param 'delta' to override 'epsilon' in prior profile, actual: epsilon in layered parameters")
 	}
-	if _, ok := vals["epsilon"]; !ok {
-		t.Errorf("expected: param 'epsilon' to override 'delta' in prior profile, actual: epsilon not in layered parameters")
+	if _, ok := vals["delta"]; !ok {
+		t.Errorf("expected: param 'delta' to override 'epsilon' in prior profile, actual: delta not in layered parameters")
 	}
 	if _, ok := vals["zeta"]; !ok {
 		t.Errorf("expected: param 'zeta' with no ConfigFile+Name in another profile to be in layered parameters, actual: zeta not in layered parameters")
 	}
-	if _, ok := vals["theta"]; !ok {
-		t.Errorf("expected: param 'theta' to override 'eta' and 'iota' in prior profile, actual: theta not in layered parameters")
+	if _, ok := vals["iota"]; !ok {
+		t.Errorf("expected: param 'iota' to override 'eta' and 'theta' in prior profile, actual: iota not in layered parameters")
 	}
 	if _, ok := vals["eta"]; ok {
-		t.Errorf("expected: param 'theta' to override 'eta' and 'iota' in prior profile, actual: eta in layered parameters")
+		t.Errorf("expected: param 'iota' to override 'eta' and 'theta' in prior profile, actual: eta in layered parameters")
 	}
-	if _, ok := vals["iota"]; ok {
-		t.Errorf("expected: param 'theta' to override 'eta' and 'iota' in prior profile, actual: iota in layered parameters")
+	if _, ok := vals["theta"]; ok {
+		t.Errorf("expected: param 'iota' to override 'eta' and 'theta' in prior profile, actual: theta in layered parameters")
 	}
 }
 

lib/go-atscfg/parentdotconfig_test.go

@@ -3734,13 +3734,13 @@ func TestMakeParentDotConfigTopologiesServerMultipleProfileParams(t *testing.T)
 			Name:       ParentConfigCacheParamWeight,
 			ConfigFile: "parent.config",
 			Value:      "100",
-			Profiles:   []byte(`["serverprofile0"]`),
+			Profiles:   []byte(`["serverprofile1"]`),
 		},
 		tc.Parameter{
 			Name:       ParentConfigCacheParamWeight,
 			ConfigFile: "parent.config",
 			Value:      "200",
-			Profiles:   []byte(`["serverprofile1"]`),
+			Profiles:   []byte(`["serverprofile0"]`),
 		},
 	}