Backport of NET-2903 Normalize weight for http routes into release/1.15.x (#16532)

* backport of commit 10ef73a5a6

* backport of commit 99f5b726d2

* NET-2903 Normalize weight for http routes (#16512)

* NET-2903 Normalize weight for http routes

* Update website/content/docs/connect/gateways/api-gateway/configuration/http-route.mdx

Co-authored-by: trujillo-adam <47586768+trujillo-adam@users.noreply.github.com>

---------

Co-authored-by: Melisa Griffin <melisa.griffin@hashicorp.com>
Co-authored-by: Melisa Griffin <missylbytes@users.noreply.github.com>
Co-authored-by: trujillo-adam <47586768+trujillo-adam@users.noreply.github.com>

.changelog/16512.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+gateways: fix HTTPRoute bug where service weights could be less than or equal to 0 and result in a downstream envoy protocol error
+```

agent/structs/config_entry_routes.go

@@ -100,7 +100,9 @@ func (e *HTTPRouteConfigEntry) Normalize() error {
 
 func normalizeHTTPService(service HTTPService) HTTPService {
 	service.EnterpriseMeta.Normalize()
-
+	if service.Weight <= 0 {
+		service.Weight = 1
+	}
 	return service
 }
 

agent/structs/config_entry_routes_test.go

@@ -262,6 +262,28 @@ func TestHTTPRoute(t *testing.T) {
 				}},
 			},
 		},
+		"rule normalizes service weight": {
+			entry: &HTTPRouteConfigEntry{
+				Kind: HTTPRoute,
+				Name: "route-one",
+				Rules: []HTTPRouteRule{{
+					Services: []HTTPService{
+						{
+							Name:   "test",
+							Weight: 0,
+						},
+						{
+							Name:   "test2",
+							Weight: -1,
+						}},
+				}},
+			},
+			check: func(t *testing.T, entry ConfigEntry) {
+				route := entry.(*HTTPRouteConfigEntry)
+				require.Equal(t, 1, route.Rules[0].Services[0].Weight)
+				require.Equal(t, 1, route.Rules[0].Services[1].Weight)
+			},
+		},
 	}
 	testConfigEntryNormalizeAndValidate(t, cases)
 }

website/content/docs/connect/gateways/api-gateway/configuration/http-route.mdx

@@ -630,7 +630,8 @@ Specifies the Enterprise [admin partition](/consul/docs/enterprise/admin-partiti
 
 ### `Rules[].Services[].Weight`
 
-Specifies the proportion of requests forwarded to the specified service. The
+Specifies the proportion of requests forwarded to the specified service. If no weight is specified, or if the specified
+weight is set to less than or equal to `0`, the weight is normalized to `1`. The
 proportion is determined by dividing the value of the weight by the sum of all
 weights in the service list. For non-zero values, there may be some deviation
 from the exact proportion depending on the precision an implementation