opa: pass headers to OPA service (#64)

Signed-off-by: spacewander <[email protected]>

pkg/request/request.go

@@ -15,3 +15,21 @@ func GetUrl(header api.RequestHeaderMap) *url.URL {
 	}
 	return uri
 }
+
+// GetHeaders returns a plain map represents the headers. The returned headers won't
+// contain any pseudo header like `:authority`.
+func GetHeaders(header api.RequestHeaderMap) map[string][]string {
+	hdr := map[string][]string{}
+	header.Range(func(k, v string) bool {
+		if k[0] == ':' {
+			return true
+		}
+		if entry, ok := hdr[k]; !ok {
+			hdr[k] = []string{v}
+		} else {
+			hdr[k] = append(entry, v)
+		}
+		return true
+	})
+	return hdr
+}

plugins/opa/README.md

@@ -31,15 +31,21 @@ Here is the JSON data Moe sends to the OPA:
                 "b": [""]
             },
             "method": "GET",
-            "host": "localhost"
+            "host": "localhost:10000",
+            "headers": {
+                "fruit": ["apple", "banana"],
+                "pet": ["dog"]
+            }
         }
     }
 }
 ```
 
 Note that:
 
-* `method` is always uppercase, while `host` and `scheme` are always lowecase.
+* `method` is always uppercase, while `host`, `headers` and `scheme` are always lowecase.
+* `host` will contain the port if the `:authority` header sent by the client has the port.
+* Multiple `headers` and `query` in the same name will be passed in an array.
 
 The data can be read as `input` document in OPA.
 

plugins/opa/filter.go

@@ -33,11 +33,13 @@ var opaResponse struct {
 
 func (f *filter) buildInput(header api.RequestHeaderMap) map[string]interface{} {
 	uri := request.GetUrl(header)
+	headers := request.GetHeaders(header)
 	req := map[string]interface{}{
-		"method": header.Method(),
-		"scheme": header.Scheme(),
-		"host":   header.Host(),
-		"path":   uri.Path,
+		"method":  header.Method(),
+		"scheme":  header.Scheme(),
+		"host":    header.Host(),
+		"path":    uri.Path,
+		"headers": headers,
 	}
 	if uri.RawQuery != "" {
 		req["query"] = map[string][]string(uri.Query())

plugins/opa/filter_test.go

@@ -30,6 +30,8 @@ func TestOpaRemote(t *testing.T) {
 	})(cb)
 	hdr := envoy.NewRequestHeaderMap(http.Header(map[string][]string{
 		":path": {"/?a=1&b&c=true&c=foo"},
+		"pet":   {"cat"},
+		"fruit": {"apple", "banana"},
 	}))
 
 	tests := []struct {
@@ -53,6 +55,10 @@ func TestOpaRemote(t *testing.T) {
 						"b": []interface{}{""},
 						"c": []interface{}{"true", "foo"},
 					},
+					"headers": map[string]interface{}{
+						"pet":   []interface{}{"cat"},
+						"fruit": []interface{}{"apple", "banana"},
+					},
 				}, input["input"].(map[string]interface{})["request"])
 			},
 		},